blob: 0d491ad15b66ad92eb12b480331b32e841675281 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Shared application/kernel submission and completion ring pairs, for
* supporting fast/efficient IO.
*
* A note on the read/write ordering memory barriers that are matched between
* the application and kernel side.
*
* After the application reads the CQ ring tail, it must use an
* appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
* before writing the tail (using smp_load_acquire to read the tail will
* do). It also needs a smp_mb() before updating CQ head (ordering the
* entry load(s) with the head store), pairing with an implicit barrier
* through a control-dependency in io_get_cqe (smp_store_release to
* store head will do). Failure to do so could lead to reading invalid
* CQ entries.
*
* Likewise, the application must use an appropriate smp_wmb() before
* writing the SQ tail (ordering SQ entry stores with the tail store),
* which pairs with smp_load_acquire in io_get_sqring (smp_store_release
* to store the tail will do). And it needs a barrier ordering the SQ
* head load before writing new SQ entries (smp_load_acquire to read
* head will do).
*
* When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
* needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
* updating the SQ tail; a full memory barrier smp_mb() is needed
* between.
*
* Also see the examples in the liburing library:
*
* git://git.kernel.dk/liburing
*
* io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
* from data shared between the kernel and application. This is done both
* for ordering purposes, but also to ensure that once a value is loaded from
* data that the application could potentially modify, it remains stable.
*
* Copyright (C) 2018-2019 Jens Axboe
* Copyright (c) 2018-2019 Christoph Hellwig
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <net/compat.h>
#include <linux/refcount.h>
#include <linux/uio.h>
#include <linux/bits.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/blk-mq.h>
#include <linux/bvec.h>
#include <linux/net.h>
#include <net/sock.h>
#include <net/af_unix.h>
#include <net/scm.h>
#include <linux/anon_inodes.h>
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
#include <linux/sizes.h>
#include <linux/hugetlb.h>
#include <linux/highmem.h>
#include <linux/namei.h>
#include <linux/fsnotify.h>
#include <linux/fadvise.h>
#include <linux/eventpoll.h>
#include <linux/splice.h>
#include <linux/task_work.h>
#include <linux/pagemap.h>
#include <linux/io_uring.h>
#include <linux/audit.h>
#include <linux/security.h>
#include <linux/xattr.h>
#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "internal.h"
#include "io-wq.h"
#define IORING_MAX_ENTRIES 32768
#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
#define IORING_SQPOLL_CAP_ENTRIES_VALUE 8
/* only define max */
#define IORING_MAX_FIXED_FILES (1U << 20)
#define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \
IORING_REGISTER_LAST + IORING_OP_LAST)
#define IO_RSRC_TAG_TABLE_SHIFT (PAGE_SHIFT - 3)
#define IO_RSRC_TAG_TABLE_MAX (1U << IO_RSRC_TAG_TABLE_SHIFT)
#define IO_RSRC_TAG_TABLE_MASK (IO_RSRC_TAG_TABLE_MAX - 1)
#define IORING_MAX_REG_BUFFERS (1U << 14)
#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
IOSQE_IO_HARDLINK | IOSQE_ASYNC)
#define SQE_VALID_FLAGS (SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \
IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)
#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
REQ_F_ASYNC_DATA)
#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
IO_REQ_CLEAN_FLAGS)
#define IO_APOLL_MULTI_POLLED (REQ_F_APOLL_MULTISHOT | REQ_F_POLLED)
#define IO_TCTX_REFS_CACHE_NR (1U << 10)
struct io_uring {
u32 head ____cacheline_aligned_in_smp;
u32 tail ____cacheline_aligned_in_smp;
};
/*
* This data is shared with the application through the mmap at offsets
* IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
*
* The offsets to the member fields are published through struct
* io_sqring_offsets when calling io_uring_setup.
*/
struct io_rings {
/*
* Head and tail offsets into the ring; the offsets need to be
* masked to get valid indices.
*
* The kernel controls head of the sq ring and the tail of the cq ring,
* and the application controls tail of the sq ring and the head of the
* cq ring.
*/
struct io_uring sq, cq;
/*
* Bitmasks to apply to head and tail offsets (constant, equals
* ring_entries - 1)
*/
u32 sq_ring_mask, cq_ring_mask;
/* Ring sizes (constant, power of 2) */
u32 sq_ring_entries, cq_ring_entries;
/*
* Number of invalid entries dropped by the kernel due to
* invalid index stored in array
*
* Written by the kernel, shouldn't be modified by the
* application (i.e. get number of "new events" by comparing to
* cached value).
*
* After a new SQ head value was read by the application this
* counter includes all submissions that were dropped reaching
* the new SQ head (and possibly more).
*/
u32 sq_dropped;
/*
* Runtime SQ flags
*
* Written by the kernel, shouldn't be modified by the
* application.
*
* The application needs a full memory barrier before checking
* for IORING_SQ_NEED_WAKEUP after updating the sq tail.
*/
atomic_t sq_flags;
/*
* Runtime CQ flags
*
* Written by the application, shouldn't be modified by the
* kernel.
*/
u32 cq_flags;
/*
* Number of completion events lost because the queue was full;
* this should be avoided by the application by making sure
* there are not more requests pending than there is space in
* the completion queue.
*
* Written by the kernel, shouldn't be modified by the
* application (i.e. get number of "new events" by comparing to
* cached value).
*
* As completion events come in out of order this counter is not
* ordered with any other data.
*/
u32 cq_overflow;
/*
* Ring buffer of completion events.
*
* The kernel writes completion events fresh every time they are
* produced, so the application is allowed to modify pending
* entries.
*/
struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
};
struct io_mapped_ubuf {
u64 ubuf;
u64 ubuf_end;
unsigned int nr_bvecs;
unsigned long acct_pages;
struct bio_vec bvec[];
};
struct io_ring_ctx;
struct io_overflow_cqe {
struct list_head list;
struct io_uring_cqe cqe;
};
/*
* FFS_SCM is only available on 64-bit archs, for 32-bit we just define it as 0
* and define IO_URING_SCM_ALL. For this case, we use SCM for all files as we
* can't safely always dereference the file when the task has exited and ring
* cleanup is done. If a file is tracked and part of SCM, then unix gc on
* process exit may reap it before __io_sqe_files_unregister() is run.
*/
#define FFS_NOWAIT 0x1UL
#define FFS_ISREG 0x2UL
#if defined(CONFIG_64BIT)
#define FFS_SCM 0x4UL
#else
#define IO_URING_SCM_ALL
#define FFS_SCM 0x0UL
#endif
#define FFS_MASK ~(FFS_NOWAIT|FFS_ISREG|FFS_SCM)
struct io_fixed_file {
/* file * with additional FFS_* flags */
unsigned long file_ptr;
};
struct io_rsrc_put {
struct list_head list;
u64 tag;
union {
void *rsrc;
struct file *file;
struct io_mapped_ubuf *buf;
};
};
struct io_file_table {
struct io_fixed_file *files;
unsigned long *bitmap;
unsigned int alloc_hint;
};
struct io_rsrc_node {
struct percpu_ref refs;
struct list_head node;
struct list_head rsrc_list;
struct io_rsrc_data *rsrc_data;
struct llist_node llist;
bool done;
};
typedef void (rsrc_put_fn)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
struct io_rsrc_data {
struct io_ring_ctx *ctx;
u64 **tags;
unsigned int nr;
rsrc_put_fn *do_put;
atomic_t refs;
struct completion done;
bool quiesce;
};
#define IO_BUFFER_LIST_BUF_PER_PAGE (PAGE_SIZE / sizeof(struct io_uring_buf))
struct io_buffer_list {
/*
* If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not,
* then these are classic provided buffers and ->buf_list is used.
*/
union {
struct list_head buf_list;
struct {
struct page **buf_pages;
struct io_uring_buf_ring *buf_ring;
};
};
__u16 bgid;
/* below is for ring provided buffers */
__u16 buf_nr_pages;
__u16 nr_entries;
__u16 head;
__u16 mask;
};
struct io_buffer {
struct list_head list;
__u64 addr;
__u32 len;
__u16 bid;
__u16 bgid;
};
struct io_restriction {
DECLARE_BITMAP(register_op, IORING_REGISTER_LAST);
DECLARE_BITMAP(sqe_op, IORING_OP_LAST);
u8 sqe_flags_allowed;
u8 sqe_flags_required;
bool registered;
};
enum {
IO_SQ_THREAD_SHOULD_STOP = 0,
IO_SQ_THREAD_SHOULD_PARK,
};
struct io_sq_data {
refcount_t refs;
atomic_t park_pending;
struct mutex lock;
/* ctx's that are using this sqd */
struct list_head ctx_list;
struct task_struct *thread;
struct wait_queue_head wait;
unsigned sq_thread_idle;
int sq_cpu;
pid_t task_pid;
pid_t task_tgid;
unsigned long state;
struct completion exited;
};
#define IO_COMPL_BATCH 32
#define IO_REQ_CACHE_SIZE 32
#define IO_REQ_ALLOC_BATCH 8
struct io_submit_link {
struct io_kiocb *head;
struct io_kiocb *last;
};
struct io_submit_state {
/* inline/task_work completion list, under ->uring_lock */
struct io_wq_work_node free_list;
/* batch completion logic */
struct io_wq_work_list compl_reqs;
struct io_submit_link link;
bool plug_started;
bool need_plug;
bool flush_cqes;
unsigned short submit_nr;
struct blk_plug plug;
};
struct io_ev_fd {
struct eventfd_ctx *cq_ev_fd;
unsigned int eventfd_async: 1;
struct rcu_head rcu;
};
#define BGID_ARRAY 64
struct io_ring_ctx {
/* const or read-mostly hot data */
struct {
struct percpu_ref refs;
struct io_rings *rings;
unsigned int flags;
enum task_work_notify_mode notify_method;
unsigned int compat: 1;
unsigned int drain_next: 1;
unsigned int restricted: 1;
unsigned int off_timeout_used: 1;
unsigned int drain_active: 1;
unsigned int drain_disabled: 1;
unsigned int has_evfd: 1;
unsigned int syscall_iopoll: 1;
} ____cacheline_aligned_in_smp;
/* submission data */
struct {
struct mutex uring_lock;
/*
* Ring buffer of indices into array of io_uring_sqe, which is
* mmapped by the application using the IORING_OFF_SQES offset.
*
* This indirection could e.g. be used to assign fixed
* io_uring_sqe entries to operations and only submit them to
* the queue when needed.
*
* The kernel modifies neither the indices array nor the entries
* array.
*/
u32 *sq_array;
struct io_uring_sqe *sq_sqes;
unsigned cached_sq_head;
unsigned sq_entries;
struct list_head defer_list;
/*
* Fixed resources fast path, should be accessed only under
* uring_lock, and updated through io_uring_register(2)
*/
struct io_rsrc_node *rsrc_node;
int rsrc_cached_refs;
atomic_t cancel_seq;
struct io_file_table file_table;
unsigned nr_user_files;
unsigned nr_user_bufs;
struct io_mapped_ubuf **user_bufs;
struct io_submit_state submit_state;
struct io_buffer_list *io_bl;
struct xarray io_bl_xa;
struct list_head io_buffers_cache;
struct list_head timeout_list;
struct list_head ltimeout_list;
struct list_head cq_overflow_list;
struct list_head apoll_cache;
struct xarray personalities;
u32 pers_next;
unsigned sq_thread_idle;
} ____cacheline_aligned_in_smp;
/* IRQ completion list, under ->completion_lock */
struct io_wq_work_list locked_free_list;
unsigned int locked_free_nr;
const struct cred *sq_creds; /* cred used for __io_sq_thread() */
struct io_sq_data *sq_data; /* if using sq thread polling */
struct wait_queue_head sqo_sq_wait;
struct list_head sqd_list;
unsigned long check_cq;
struct {
/*
* We cache a range of free CQEs we can use, once exhausted it
* should go through a slower range setup, see __io_get_cqe()
*/
struct io_uring_cqe *cqe_cached;
struct io_uring_cqe *cqe_sentinel;
unsigned cached_cq_tail;
unsigned cq_entries;
struct io_ev_fd __rcu *io_ev_fd;
struct wait_queue_head cq_wait;
unsigned cq_extra;
atomic_t cq_timeouts;
unsigned cq_last_tm_flush;
} ____cacheline_aligned_in_smp;
struct {
spinlock_t completion_lock;
spinlock_t timeout_lock;
/*
* ->iopoll_list is protected by the ctx->uring_lock for
* io_uring instances that don't use IORING_SETUP_SQPOLL.
* For SQPOLL, only the single threaded io_sq_thread() will
* manipulate the list, hence no extra locking is needed there.
*/
struct io_wq_work_list iopoll_list;
struct hlist_head *cancel_hash;
unsigned cancel_hash_bits;
bool poll_multi_queue;
struct list_head io_buffers_comp;
} ____cacheline_aligned_in_smp;
struct io_restriction restrictions;
/* slow path rsrc auxilary data, used by update/register */
struct {
struct io_rsrc_node *rsrc_backup_node;
struct io_mapped_ubuf *dummy_ubuf;
struct io_rsrc_data *file_data;
struct io_rsrc_data *buf_data;
struct delayed_work rsrc_put_work;
struct llist_head rsrc_put_llist;
struct list_head rsrc_ref_list;
spinlock_t rsrc_ref_lock;
struct list_head io_buffers_pages;
};
/* Keep this last, we don't need it for the fast path */
struct {
#if defined(CONFIG_UNIX)
struct socket *ring_sock;
#endif
/* hashed buffered write serialization */
struct io_wq_hash *hash_map;
/* Only used for accounting purposes */
struct user_struct *user;
struct mm_struct *mm_account;
/* ctx exit and cancelation */
struct llist_head fallback_llist;
struct delayed_work fallback_work;
struct work_struct exit_work;
struct list_head tctx_list;
struct completion ref_comp;
u32 iowq_limits[2];
bool iowq_limits_set;
};
};
/*
* Arbitrary limit, can be raised if need be
*/
#define IO_RINGFD_REG_MAX 16
struct io_uring_task {
/* submission side */
int cached_refs;
struct xarray xa;
struct wait_queue_head wait;
const struct io_ring_ctx *last;
struct io_wq *io_wq;
struct percpu_counter inflight;
atomic_t inflight_tracked;
atomic_t in_idle;
spinlock_t task_lock;
struct io_wq_work_list task_list;
struct io_wq_work_list prio_task_list;
struct callback_head task_work;
struct file **registered_rings;
bool task_running;
};
/*
* First field must be the file pointer in all the
* iocb unions! See also 'struct kiocb' in <linux/fs.h>
*/
struct io_poll_iocb {
struct file *file;
struct wait_queue_head *head;
__poll_t events;
struct wait_queue_entry wait;
};
struct io_poll_update {
struct file *file;
u64 old_user_data;
u64 new_user_data;
__poll_t events;
bool update_events;
bool update_user_data;
};
struct io_close {
struct file *file;
int fd;
u32 file_slot;
};
struct io_timeout_data {
struct io_kiocb *req;
struct hrtimer timer;
struct timespec64 ts;
enum hrtimer_mode mode;
u32 flags;
};
struct io_accept {
struct file *file;
struct sockaddr __user *addr;
int __user *addr_len;
int flags;
u32 file_slot;
unsigned long nofile;
};
struct io_socket {
struct file *file;
int domain;
int type;
int protocol;
int flags;
u32 file_slot;
unsigned long nofile;
};
struct io_sync {
struct file *file;
loff_t len;
loff_t off;
int flags;
int mode;
};
struct io_cancel {
struct file *file;
u64 addr;
u32 flags;
s32 fd;
};
struct io_timeout {
struct file *file;
u32 off;
u32 target_seq;
struct list_head list;
/* head of the link, used by linked timeouts only */
struct io_kiocb *head;
/* for linked completions */
struct io_kiocb *prev;
};
struct io_timeout_rem {
struct file *file;
u64 addr;
/* timeout update */
struct timespec64 ts;
u32 flags;
bool ltimeout;
};
struct io_rw {
/* NOTE: kiocb has the file as the first member, so don't do it here */
struct kiocb kiocb;
u64 addr;
u32 len;
rwf_t flags;
};
struct io_connect {
struct file *file;
struct sockaddr __user *addr;
int addr_len;
};
struct io_sr_msg {
struct file *file;
union {
struct compat_msghdr __user *umsg_compat;
struct user_msghdr __user *umsg;
void __user *buf;
};
int msg_flags;
size_t len;
size_t done_io;
unsigned int flags;
};
struct io_open {
struct file *file;
int dfd;
u32 file_slot;
struct filename *filename;
struct open_how how;
unsigned long nofile;
};
struct io_rsrc_update {
struct file *file;
u64 arg;
u32 nr_args;
u32 offset;
};
struct io_fadvise {
struct file *file;
u64 offset;
u32 len;
u32 advice;
};
struct io_madvise {
struct file *file;
u64 addr;
u32 len;
u32 advice;
};
struct io_epoll {
struct file *file;
int epfd;
int op;
int fd;
struct epoll_event event;
};
struct io_splice {
struct file *file_out;
loff_t off_out;
loff_t off_in;
u64 len;
int splice_fd_in;
unsigned int flags;
};
struct io_provide_buf {
struct file *file;
__u64 addr;
__u32 len;
__u32 bgid;
__u16 nbufs;
__u16 bid;
};
struct io_statx {
struct file *file;
int dfd;
unsigned int mask;
unsigned int flags;
struct filename *filename;
struct statx __user *buffer;
};
struct io_shutdown {
struct file *file;
int how;
};
struct io_rename {
struct file *file;
int old_dfd;
int new_dfd;
struct filename *oldpath;
struct filename *newpath;
int flags;
};
struct io_unlink {
struct file *file;
int dfd;
int flags;
struct filename *filename;
};
struct io_mkdir {
struct file *file;
int dfd;
umode_t mode;
struct filename *filename;
};
struct io_symlink {
struct file *file;
int new_dfd;
struct filename *oldpath;
struct filename *newpath;
};
struct io_hardlink {
struct file *file;
int old_dfd;
int new_dfd;
struct filename *oldpath;
struct filename *newpath;
int flags;
};
struct io_msg {
struct file *file;
u64 user_data;
u32 len;
};
struct io_async_connect {
struct sockaddr_storage address;
};
struct io_async_msghdr {
struct iovec fast_iov[UIO_FASTIOV];
/* points to an allocated iov, if NULL we use fast_iov instead */
struct iovec *free_iov;
struct sockaddr __user *uaddr;
struct msghdr msg;
struct sockaddr_storage addr;
};
struct io_rw_state {
struct iov_iter iter;
struct iov_iter_state iter_state;
struct iovec fast_iov[UIO_FASTIOV];
};
struct io_async_rw {
struct io_rw_state s;
const struct iovec *free_iovec;
size_t bytes_done;
struct wait_page_queue wpq;
};
struct io_xattr {
struct file *file;
struct xattr_ctx ctx;
struct filename *filename;
};
enum {
REQ_F_FIXED_FILE_BIT = IOSQE_FIXED_FILE_BIT,
REQ_F_IO_DRAIN_BIT = IOSQE_IO_DRAIN_BIT,
REQ_F_LINK_BIT = IOSQE_IO_LINK_BIT,
REQ_F_HARDLINK_BIT = IOSQE_IO_HARDLINK_BIT,
REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT,
REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT,
REQ_F_CQE_SKIP_BIT = IOSQE_CQE_SKIP_SUCCESS_BIT,
/* first byte is taken by user flags, shift it to not overlap */
REQ_F_FAIL_BIT = 8,
REQ_F_INFLIGHT_BIT,
REQ_F_CUR_POS_BIT,
REQ_F_NOWAIT_BIT,
REQ_F_LINK_TIMEOUT_BIT,
REQ_F_NEED_CLEANUP_BIT,
REQ_F_POLLED_BIT,
REQ_F_BUFFER_SELECTED_BIT,
REQ_F_BUFFER_RING_BIT,
REQ_F_COMPLETE_INLINE_BIT,
REQ_F_REISSUE_BIT,
REQ_F_CREDS_BIT,
REQ_F_REFCOUNT_BIT,
REQ_F_ARM_LTIMEOUT_BIT,
REQ_F_ASYNC_DATA_BIT,
REQ_F_SKIP_LINK_CQES_BIT,
REQ_F_SINGLE_POLL_BIT,
REQ_F_DOUBLE_POLL_BIT,
REQ_F_PARTIAL_IO_BIT,
REQ_F_CQE32_INIT_BIT,
REQ_F_APOLL_MULTISHOT_BIT,
/* keep async read/write and isreg together and in order */
REQ_F_SUPPORT_NOWAIT_BIT,
REQ_F_ISREG_BIT,
/* not a real bit, just to check we're not overflowing the space */
__REQ_F_LAST_BIT,
};
enum {
/* ctx owns file */
REQ_F_FIXED_FILE = BIT(REQ_F_FIXED_FILE_BIT),
/* drain existing IO first */
REQ_F_IO_DRAIN = BIT(REQ_F_IO_DRAIN_BIT),
/* linked sqes */
REQ_F_LINK = BIT(REQ_F_LINK_BIT),
/* doesn't sever on completion < 0 */
REQ_F_HARDLINK = BIT(REQ_F_HARDLINK_BIT),
/* IOSQE_ASYNC */
REQ_F_FORCE_ASYNC = BIT(REQ_F_FORCE_ASYNC_BIT),
/* IOSQE_BUFFER_SELECT */
REQ_F_BUFFER_SELECT = BIT(REQ_F_BUFFER_SELECT_BIT),
/* IOSQE_CQE_SKIP_SUCCESS */
REQ_F_CQE_SKIP = BIT(REQ_F_CQE_SKIP_BIT),
/* fail rest of links */
REQ_F_FAIL = BIT(REQ_F_FAIL_BIT),
/* on inflight list, should be cancelled and waited on exit reliably */
REQ_F_INFLIGHT = BIT(REQ_F_INFLIGHT_BIT),
/* read/write uses file position */
REQ_F_CUR_POS = BIT(REQ_F_CUR_POS_BIT),
/* must not punt to workers */
REQ_F_NOWAIT = BIT(REQ_F_NOWAIT_BIT),
/* has or had linked timeout */
REQ_F_LINK_TIMEOUT = BIT(REQ_F_LINK_TIMEOUT_BIT),
/* needs cleanup */
REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT),
/* already went through poll handler */
REQ_F_POLLED = BIT(REQ_F_POLLED_BIT),
/* buffer already selected */
REQ_F_BUFFER_SELECTED = BIT(REQ_F_BUFFER_SELECTED_BIT),
/* buffer selected from ring, needs commit */
REQ_F_BUFFER_RING = BIT(REQ_F_BUFFER_RING_BIT),
/* completion is deferred through io_comp_state */
REQ_F_COMPLETE_INLINE = BIT(REQ_F_COMPLETE_INLINE_BIT),
/* caller should reissue async */
REQ_F_REISSUE = BIT(REQ_F_REISSUE_BIT),
/* supports async reads/writes */
REQ_F_SUPPORT_NOWAIT = BIT(REQ_F_SUPPORT_NOWAIT_BIT),
/* regular file */
REQ_F_ISREG = BIT(REQ_F_ISREG_BIT),
/* has creds assigned */
REQ_F_CREDS = BIT(REQ_F_CREDS_BIT),
/* skip refcounting if not set */
REQ_F_REFCOUNT = BIT(REQ_F_REFCOUNT_BIT),
/* there is a linked timeout that has to be armed */
REQ_F_ARM_LTIMEOUT = BIT(REQ_F_ARM_LTIMEOUT_BIT),
/* ->async_data allocated */
REQ_F_ASYNC_DATA = BIT(REQ_F_ASYNC_DATA_BIT),
/* don't post CQEs while failing linked requests */
REQ_F_SKIP_LINK_CQES = BIT(REQ_F_SKIP_LINK_CQES_BIT),
/* single poll may be active */
REQ_F_SINGLE_POLL = BIT(REQ_F_SINGLE_POLL_BIT),
/* double poll may active */
REQ_F_DOUBLE_POLL = BIT(REQ_F_DOUBLE_POLL_BIT),
/* request has already done partial IO */
REQ_F_PARTIAL_IO = BIT(REQ_F_PARTIAL_IO_BIT),
/* fast poll multishot mode */
REQ_F_APOLL_MULTISHOT = BIT(REQ_F_APOLL_MULTISHOT_BIT),
/* ->extra1 and ->extra2 are initialised */
REQ_F_CQE32_INIT = BIT(REQ_F_CQE32_INIT_BIT),
};
struct async_poll {
struct io_poll_iocb poll;
struct io_poll_iocb *double_poll;
};
typedef void (*io_req_tw_func_t)(struct io_kiocb *req, bool *locked);
struct io_task_work {
union {
struct io_wq_work_node node;
struct llist_node fallback_node;
};
io_req_tw_func_t func;
};
enum {
IORING_RSRC_FILE = 0,
IORING_RSRC_BUFFER = 1,
};
struct io_cqe {
__u64 user_data;
__s32 res;
/* fd initially, then cflags for completion */
union {
__u32 flags;
int fd;
};
};
enum {
IO_CHECK_CQ_OVERFLOW_BIT,
IO_CHECK_CQ_DROPPED_BIT,
};
/*
* NOTE! Each of the iocb union members has the file pointer
* as the first entry in their struct definition. So you can
* access the file pointer through any of the sub-structs,
* or directly as just 'file' in this struct.
*/
struct io_kiocb {
union {
struct file *file;
struct io_rw rw;
struct io_poll_iocb poll;
struct io_poll_update poll_update;
struct io_accept accept;
struct io_sync sync;
struct io_cancel cancel;
struct io_timeout timeout;
struct io_timeout_rem timeout_rem;
struct io_connect connect;
struct io_sr_msg sr_msg;
struct io_open open;
struct io_close close;
struct io_rsrc_update rsrc_update;
struct io_fadvise fadvise;
struct io_madvise madvise;
struct io_epoll epoll;
struct io_splice splice;
struct io_provide_buf pbuf;
struct io_statx statx;
struct io_shutdown shutdown;
struct io_rename rename;
struct io_unlink unlink;
struct io_mkdir mkdir;
struct io_symlink symlink;
struct io_hardlink hardlink;
struct io_msg msg;
struct io_xattr xattr;
struct io_socket sock;
struct io_uring_cmd uring_cmd;
};
u8 opcode;
/* polled IO has completed */
u8 iopoll_completed;
/*
* Can be either a fixed buffer index, or used with provided buffers.
* For the latter, before issue it points to the buffer group ID,
* and after selection it points to the buffer ID itself.
*/
u16 buf_index;
unsigned int flags;
struct io_cqe cqe;
struct io_ring_ctx *ctx;
struct task_struct *task;
struct io_rsrc_node *rsrc_node;
union {
/* store used ubuf, so we can prevent reloading */
struct io_mapped_ubuf *imu;
/* stores selected buf, valid IFF REQ_F_BUFFER_SELECTED is set */
struct io_buffer *kbuf;
/*
* stores buffer ID for ring provided buffers, valid IFF
* REQ_F_BUFFER_RING is set.
*/
struct io_buffer_list *buf_list;
};
union {
/* used by request caches, completion batching and iopoll */
struct io_wq_work_node comp_list;
/* cache ->apoll->events */
__poll_t apoll_events;
};
atomic_t refs;
atomic_t poll_refs;
struct io_task_work io_task_work;
/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
union {
struct hlist_node hash_node;
struct {
u64 extra1;
u64 extra2;
};
};
/* internal polling, see IORING_FEAT_FAST_POLL */
struct async_poll *apoll;
/* opcode allocated if it needs to store data for async defer */
void *async_data;
/* linked requests, IFF REQ_F_HARDLINK or REQ_F_LINK are set */
struct io_kiocb *link;
/* custom credentials, valid IFF REQ_F_CREDS is set */
const struct cred *creds;
struct io_wq_work work;
};
struct io_tctx_node {
struct list_head ctx_node;
struct task_struct *task;
struct io_ring_ctx *ctx;
};
struct io_defer_entry {
struct list_head list;
struct io_kiocb *req;
u32 seq;
};
struct io_cancel_data {
struct io_ring_ctx *ctx;
union {
u64 data;
struct file *file;
};
u32 flags;
int seq;
};
/*
* The URING_CMD payload starts at 'cmd' in the first sqe, and continues into
* the following sqe if SQE128 is used.
*/
#define uring_cmd_pdu_size(is_sqe128) \
((1 + !!(is_sqe128)) * sizeof(struct io_uring_sqe) - \
offsetof(struct io_uring_sqe, cmd))
struct io_op_def {
/* needs req->file assigned */
unsigned needs_file : 1;
/* should block plug */
unsigned plug : 1;
/* hash wq insertion if file is a regular file */
unsigned hash_reg_file : 1;
/* unbound wq insertion if file is a non-regular file */
unsigned unbound_nonreg_file : 1;
/* set if opcode supports polled "wait" */
unsigned pollin : 1;
unsigned pollout : 1;
unsigned poll_exclusive : 1;
/* op supports buffer selection */
unsigned buffer_select : 1;
/* do prep async if is going to be punted */
unsigned needs_async_setup : 1;
/* opcode is not supported by this kernel */
unsigned not_supported : 1;
/* skip auditing */
unsigned audit_skip : 1;
/* supports ioprio */
unsigned ioprio : 1;
/* supports iopoll */
unsigned iopoll : 1;
/* size of async data needed, if any */
unsigned short async_size;
};
static const struct io_op_def io_op_defs[] = {
[IORING_OP_NOP] = {
.audit_skip = 1,
.iopoll = 1,
},
[IORING_OP_READV] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.needs_async_setup = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.async_size = sizeof(struct io_async_rw),
},
[IORING_OP_WRITEV] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.needs_async_setup = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.async_size = sizeof(struct io_async_rw),
},
[IORING_OP_FSYNC] = {
.needs_file = 1,
.audit_skip = 1,
},
[IORING_OP_READ_FIXED] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.async_size = sizeof(struct io_async_rw),
},
[IORING_OP_WRITE_FIXED] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.async_size = sizeof(struct io_async_rw),
},
[IORING_OP_POLL_ADD] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.audit_skip = 1,
},
[IORING_OP_POLL_REMOVE] = {
.audit_skip = 1,
},
[IORING_OP_SYNC_FILE_RANGE] = {
.needs_file = 1,
.audit_skip = 1,
},
[IORING_OP_SENDMSG] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.needs_async_setup = 1,
.ioprio = 1,
.async_size = sizeof(struct io_async_msghdr),
},
[IORING_OP_RECVMSG] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.needs_async_setup = 1,
.ioprio = 1,
.async_size = sizeof(struct io_async_msghdr),
},
[IORING_OP_TIMEOUT] = {
.audit_skip = 1,
.async_size = sizeof(struct io_timeout_data),
},
[IORING_OP_TIMEOUT_REMOVE] = {
/* used by timeout updates' prep() */
.audit_skip = 1,
},
[IORING_OP_ACCEPT] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.poll_exclusive = 1,
.ioprio = 1, /* used for flags */
},
[IORING_OP_ASYNC_CANCEL] = {
.audit_skip = 1,
},
[IORING_OP_LINK_TIMEOUT] = {
.audit_skip = 1,
.async_size = sizeof(struct io_timeout_data),
},
[IORING_OP_CONNECT] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.needs_async_setup = 1,
.async_size = sizeof(struct io_async_connect),
},
[IORING_OP_FALLOCATE] = {
.needs_file = 1,
},
[IORING_OP_OPENAT] = {},
[IORING_OP_CLOSE] = {},
[IORING_OP_FILES_UPDATE] = {
.audit_skip = 1,
.iopoll = 1,
},
[IORING_OP_STATX] = {
.audit_skip = 1,
},
[IORING_OP_READ] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.async_size = sizeof(struct io_async_rw),
},
[IORING_OP_WRITE] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.async_size = sizeof(struct io_async_rw),
},
[IORING_OP_FADVISE] = {
.needs_file = 1,
.audit_skip = 1,
},
[IORING_OP_MADVISE] = {},
[IORING_OP_SEND] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.audit_skip = 1,
.ioprio = 1,
},
[IORING_OP_RECV] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.audit_skip = 1,
.ioprio = 1,
},
[IORING_OP_OPENAT2] = {
},
[IORING_OP_EPOLL_CTL] = {
.unbound_nonreg_file = 1,
.audit_skip = 1,
},
[IORING_OP_SPLICE] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.audit_skip = 1,
},
[IORING_OP_PROVIDE_BUFFERS] = {
.audit_skip = 1,
.iopoll = 1,
},
[IORING_OP_REMOVE_BUFFERS] = {
.audit_skip = 1,
.iopoll = 1,
},
[IORING_OP_TEE] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.audit_skip = 1,
},
[IORING_OP_SHUTDOWN] = {
.needs_file = 1,
},
[IORING_OP_RENAMEAT] = {},
[IORING_OP_UNLINKAT] = {},
[IORING_OP_MKDIRAT] = {},
[IORING_OP_SYMLINKAT] = {},
[IORING_OP_LINKAT] = {},
[IORING_OP_MSG_RING] = {
.needs_file = 1,
.iopoll = 1,
},
[IORING_OP_FSETXATTR] = {
.needs_file = 1
},
[IORING_OP_SETXATTR] = {},
[IORING_OP_FGETXATTR] = {
.needs_file = 1
},
[IORING_OP_GETXATTR] = {},
[IORING_OP_SOCKET] = {
.audit_skip = 1,
},
[IORING_OP_URING_CMD] = {
.needs_file = 1,
.plug = 1,
.needs_async_setup = 1,
.async_size = uring_cmd_pdu_size(1),
},
};
/* requests with any of those set should undergo io_disarm_next() */
#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
static bool io_disarm_next(struct io_kiocb *req);
static void io_uring_del_tctx_node(unsigned long index);
static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
struct task_struct *task,
bool cancel_all);
static void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
static void __io_req_complete_post(struct io_kiocb *req, s32 res, u32 cflags);
static void io_dismantle_req(struct io_kiocb *req);
static void io_queue_linked_timeout(struct io_kiocb *req);
static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
struct io_uring_rsrc_update2 *up,
unsigned nr_args);
static void io_clean_op(struct io_kiocb *req);
static inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
unsigned issue_flags);
static struct file *io_file_get_normal(struct io_kiocb *req, int fd);
static void io_queue_sqe(struct io_kiocb *req);
static void io_rsrc_put_work(struct work_struct *work);
static void io_req_task_queue(struct io_kiocb *req);
static void __io_submit_flush_completions(struct io_ring_ctx *ctx);
static int io_req_prep_async(struct io_kiocb *req);
static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
unsigned int issue_flags, u32 slot_index);
static int __io_close_fixed(struct io_kiocb *req, unsigned int issue_flags,
unsigned int offset);
static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags);
static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer);
static void io_eventfd_signal(struct io_ring_ctx *ctx);
static void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags);
static struct kmem_cache *req_cachep;
static const struct file_operations io_uring_fops;
const char *io_uring_get_opcode(u8 opcode)
{
switch ((enum io_uring_op)opcode) {
case IORING_OP_NOP:
return "NOP";
case IORING_OP_READV:
return "READV";
case IORING_OP_WRITEV:
return "WRITEV";
case IORING_OP_FSYNC:
return "FSYNC";
case IORING_OP_READ_FIXED:
return "READ_FIXED";
case IORING_OP_WRITE_FIXED:
return "WRITE_FIXED";
case IORING_OP_POLL_ADD:
return "POLL_ADD";
case IORING_OP_POLL_REMOVE:
return "POLL_REMOVE";
case IORING_OP_SYNC_FILE_RANGE:
return "SYNC_FILE_RANGE";
case IORING_OP_SENDMSG:
return "SENDMSG";
case IORING_OP_RECVMSG:
return "RECVMSG";
case IORING_OP_TIMEOUT:
return "TIMEOUT";
case IORING_OP_TIMEOUT_REMOVE:
return "TIMEOUT_REMOVE";
case IORING_OP_ACCEPT:
return "ACCEPT";
case IORING_OP_ASYNC_CANCEL:
return "ASYNC_CANCEL";
case IORING_OP_LINK_TIMEOUT:
return "LINK_TIMEOUT";
case IORING_OP_CONNECT:
return "CONNECT";
case IORING_OP_FALLOCATE:
return "FALLOCATE";
case IORING_OP_OPENAT:
return "OPENAT";
case IORING_OP_CLOSE:
return "CLOSE";
case IORING_OP_FILES_UPDATE:
return "FILES_UPDATE";
case IORING_OP_STATX:
return "STATX";
case IORING_OP_READ:
return "READ";
case IORING_OP_WRITE:
return "WRITE";
case IORING_OP_FADVISE:
return "FADVISE";
case IORING_OP_MADVISE:
return "MADVISE";
case IORING_OP_SEND:
return "SEND";
case IORING_OP_RECV:
return "RECV";
case IORING_OP_OPENAT2:
return "OPENAT2";
case IORING_OP_EPOLL_CTL:
return "EPOLL_CTL";
case IORING_OP_SPLICE:
return "SPLICE";
case IORING_OP_PROVIDE_BUFFERS:
return "PROVIDE_BUFFERS";
case IORING_OP_REMOVE_BUFFERS:
return "REMOVE_BUFFERS";
case IORING_OP_TEE:
return "TEE";
case IORING_OP_SHUTDOWN:
return "SHUTDOWN";
case IORING_OP_RENAMEAT:
return "RENAMEAT";
case IORING_OP_UNLINKAT:
return "UNLINKAT";
case IORING_OP_MKDIRAT:
return "MKDIRAT";
case IORING_OP_SYMLINKAT:
return "SYMLINKAT";
case IORING_OP_LINKAT:
return "LINKAT";
case IORING_OP_MSG_RING:
return "MSG_RING";
case IORING_OP_FSETXATTR:
return "FSETXATTR";
case IORING_OP_SETXATTR:
return "SETXATTR";
case IORING_OP_FGETXATTR:
return "FGETXATTR";
case IORING_OP_GETXATTR:
return "GETXATTR";
case IORING_OP_SOCKET:
return "SOCKET";
case IORING_OP_URING_CMD:
return "URING_CMD";
case IORING_OP_LAST:
return "INVALID";
}
return "INVALID";
}
struct sock *io_uring_get_socket(struct file *file)
{
#if defined(CONFIG_UNIX)
if (file->f_op == &io_uring_fops) {
struct io_ring_ctx *ctx = file->private_data;
return ctx->ring_sock->sk;
}
#endif
return NULL;
}
EXPORT_SYMBOL(io_uring_get_socket);
#if defined(CONFIG_UNIX)
static inline bool io_file_need_scm(struct file *filp)
{
#if defined(IO_URING_SCM_ALL)
return true;
#else
return !!unix_get_socket(filp);
#endif
}
#else
static inline bool io_file_need_scm(struct file *filp)
{
return false;
}
#endif
static void io_ring_submit_unlock(struct io_ring_ctx *ctx, unsigned issue_flags)
{
lockdep_assert_held(&ctx->uring_lock);
if (issue_flags & IO_URING_F_UNLOCKED)
mutex_unlock(&ctx->uring_lock);
}
static void io_ring_submit_lock(struct io_ring_ctx *ctx, unsigned issue_flags)
{
/*
* "Normal" inline submissions always hold the uring_lock, since we
* grab it from the system call. Same is true for the SQPOLL offload.
* The only exception is when we've detached the request and issue it
* from an async worker thread, grab the lock for that case.
*/
if (issue_flags & IO_URING_F_UNLOCKED)
mutex_lock(&ctx->uring_lock);
lockdep_assert_held(&ctx->uring_lock);
}
static inline void io_tw_lock(struct io_ring_ctx *ctx, bool *locked)
{
if (!*locked) {
mutex_lock(&ctx->uring_lock);
*locked = true;
}
}
#define io_for_each_link(pos, head) \
for (pos = (head); pos; pos = pos->link)
/*
* Shamelessly stolen from the mm implementation of page reference checking,
* see commit f958d7b528b1 for details.
*/
#define req_ref_zero_or_close_to_overflow(req) \
((unsigned int) atomic_read(&(req->refs)) + 127u <= 127u)
static inline bool req_ref_inc_not_zero(struct io_kiocb *req)
{
WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
return atomic_inc_not_zero(&req->refs);
}
static inline bool req_ref_put_and_test(struct io_kiocb *req)
{
if (likely(!(req->flags & REQ_F_REFCOUNT)))
return true;
WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
return atomic_dec_and_test(&req->refs);
}
static inline void req_ref_get(struct io_kiocb *req)
{
WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
atomic_inc(&req->refs);
}
static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
{
if (!wq_list_empty(&ctx->submit_state.compl_reqs))
__io_submit_flush_completions(ctx);
}
static inline void __io_req_set_refcount(struct io_kiocb *req, int nr)
{
if (!(req->flags & REQ_F_REFCOUNT)) {
req->flags |= REQ_F_REFCOUNT;
atomic_set(&req->refs, nr);
}
}
static inline void io_req_set_refcount(struct io_kiocb *req)
{
__io_req_set_refcount(req, 1);
}
#define IO_RSRC_REF_BATCH 100
static void io_rsrc_put_node(struct io_rsrc_node *node, int nr)
{
percpu_ref_put_many(&node->refs, nr);
}
static inline void io_req_put_rsrc_locked(struct io_kiocb *req,
struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
struct io_rsrc_node *node = req->rsrc_node;
if (node) {
if (node == ctx->rsrc_node)
ctx->rsrc_cached_refs++;
else
io_rsrc_put_node(node, 1);
}
}
static inline void io_req_put_rsrc(struct io_kiocb *req)
{
if (req->rsrc_node)
io_rsrc_put_node(req->rsrc_node, 1);
}
static __cold void io_rsrc_refs_drop(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
if (ctx->rsrc_cached_refs) {
io_rsrc_put_node(ctx->rsrc_node, ctx->rsrc_cached_refs);
ctx->rsrc_cached_refs = 0;
}
}
static void io_rsrc_refs_refill(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
ctx->rsrc_cached_refs += IO_RSRC_REF_BATCH;
percpu_ref_get_many(&ctx->rsrc_node->refs, IO_RSRC_REF_BATCH);
}
static inline void io_req_set_rsrc_node(struct io_kiocb *req,
struct io_ring_ctx *ctx,
unsigned int issue_flags)
{
if (!req->rsrc_node) {
req->rsrc_node = ctx->rsrc_node;
if (!(issue_flags & IO_URING_F_UNLOCKED)) {
lockdep_assert_held(&ctx->uring_lock);
ctx->rsrc_cached_refs--;
if (unlikely(ctx->rsrc_cached_refs < 0))
io_rsrc_refs_refill(ctx);
} else {
percpu_ref_get(&req->rsrc_node->refs);
}
}
}
static unsigned int __io_put_kbuf(struct io_kiocb *req, struct list_head *list)
{
if (req->flags & REQ_F_BUFFER_RING) {
if (req->buf_list)
req->buf_list->head++;
req->flags &= ~REQ_F_BUFFER_RING;
} else {
list_add(&req->kbuf->list, list);
req->flags &= ~REQ_F_BUFFER_SELECTED;
}
return IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
}
static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
{
lockdep_assert_held(&req->ctx->completion_lock);
if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
return 0;
return __io_put_kbuf(req, &req->ctx->io_buffers_comp);
}
static inline unsigned int io_put_kbuf(struct io_kiocb *req,
unsigned issue_flags)
{
unsigned int cflags;
if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
return 0;
/*
* We can add this buffer back to two lists:
*
* 1) The io_buffers_cache list. This one is protected by the
* ctx->uring_lock. If we already hold this lock, add back to this
* list as we can grab it from issue as well.
* 2) The io_buffers_comp list. This one is protected by the
* ctx->completion_lock.
*
* We migrate buffers from the comp_list to the issue cache list
* when we need one.
*/
if (req->flags & REQ_F_BUFFER_RING) {
/* no buffers to recycle for this case */
cflags = __io_put_kbuf(req, NULL);
} else if (issue_flags & IO_URING_F_UNLOCKED) {
struct io_ring_ctx *ctx = req->ctx;
spin_lock(&ctx->completion_lock);
cflags = __io_put_kbuf(req, &ctx->io_buffers_comp);
spin_unlock(&ctx->completion_lock);
} else {
lockdep_assert_held(&req->ctx->uring_lock);
cflags = __io_put_kbuf(req, &req->ctx->io_buffers_cache);
}
return cflags;
}
static struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx,
unsigned int bgid)
{
if (ctx->io_bl && bgid < BGID_ARRAY)
return &ctx->io_bl[bgid];
return xa_load(&ctx->io_bl_xa, bgid);
}
static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_buffer_list *bl;
struct io_buffer *buf;
if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
return;
/*
* For legacy provided buffer mode, don't recycle if we already did
* IO to this buffer. For ring-mapped provided buffer mode, we should
* increment ring->head to explicitly monopolize the buffer to avoid
* multiple use.
*/
if ((req->flags & REQ_F_BUFFER_SELECTED) &&
(req->flags & REQ_F_PARTIAL_IO))
return;
/*
* We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
* the flag and hence ensure that bl->head doesn't get incremented.
* If the tail has already been incremented, hang on to it.
*/
if (req->flags & REQ_F_BUFFER_RING) {
if (req->buf_list) {
if (req->flags & REQ_F_PARTIAL_IO) {
req->buf_list->head++;
req->buf_list = NULL;
} else {
req->buf_index = req->buf_list->bgid;
req->flags &= ~REQ_F_BUFFER_RING;
}
}
return;
}
io_ring_submit_lock(ctx, issue_flags);
buf = req->kbuf;
bl = io_buffer_get_list(ctx, buf->bgid);
list_add(&buf->list, &bl->buf_list);
req->flags &= ~REQ_F_BUFFER_SELECTED;
req->buf_index = buf->bgid;
io_ring_submit_unlock(ctx, issue_flags);
}
static bool io_match_task(struct io_kiocb *head, struct task_struct *task,
bool cancel_all)
__must_hold(&req->ctx->timeout_lock)
{
struct io_kiocb *req;
if (task && head->task != task)
return false;
if (cancel_all)
return true;
io_for_each_link(req, head) {
if (req->flags & REQ_F_INFLIGHT)
return true;
}
return false;
}
static bool io_match_linked(struct io_kiocb *head)
{
struct io_kiocb *req;
io_for_each_link(req, head) {
if (req->flags & REQ_F_INFLIGHT)
return true;
}
return false;
}
/*
* As io_match_task() but protected against racing with linked timeouts.
* User must not hold timeout_lock.
*/
static bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
bool cancel_all)
{
bool matched;
if (task && head->task != task)
return false;
if (cancel_all)
return true;
if (head->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = head->ctx;
/* protect against races with linked timeouts */
spin_lock_irq(&ctx->timeout_lock);
matched = io_match_linked(head);
spin_unlock_irq(&ctx->timeout_lock);
} else {
matched = io_match_linked(head);
}
return matched;
}
static inline bool req_has_async_data(struct io_kiocb *req)
{
return req->flags & REQ_F_ASYNC_DATA;
}
static inline void req_set_fail(struct io_kiocb *req)
{
req->flags |= REQ_F_FAIL;
if (req->flags & REQ_F_CQE_SKIP) {
req->flags &= ~REQ_F_CQE_SKIP;
req->flags |= REQ_F_SKIP_LINK_CQES;
}
}
static inline void req_fail_link_node(struct io_kiocb *req, int res)
{
req_set_fail(req);
req->cqe.res = res;
}
static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
}
static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
{
struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
complete(&ctx->ref_comp);
}
static inline bool io_is_timeout_noseq(struct io_kiocb *req)
{
return !req->timeout.off;
}
static __cold void io_fallback_req_func(struct work_struct *work)
{
struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
fallback_work.work);
struct llist_node *node = llist_del_all(&ctx->fallback_llist);
struct io_kiocb *req, *tmp;
bool locked = false;
percpu_ref_get(&ctx->refs);
llist_for_each_entry_safe(req, tmp, node, io_task_work.fallback_node)
req->io_task_work.func(req, &locked);
if (locked) {
io_submit_flush_completions(ctx);
mutex_unlock(&ctx->uring_lock);
}
percpu_ref_put(&ctx->refs);
}
static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
{
struct io_ring_ctx *ctx;
int hash_bits;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return NULL;
xa_init(&ctx->io_bl_xa);
/*
* Use 5 bits less than the max cq entries, that should give us around
* 32 entries per hash list if totally full and uniformly spread.
*/
hash_bits = ilog2(p->cq_entries);
hash_bits -= 5;
if (hash_bits <= 0)
hash_bits = 1;
ctx->cancel_hash_bits = hash_bits;
ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head),
GFP_KERNEL);
if (!ctx->cancel_hash)
goto err;
__hash_init(ctx->cancel_hash, 1U << hash_bits);
ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL);
if (!ctx->dummy_ubuf)
goto err;
/* set invalid range, so io_import_fixed() fails meeting it */
ctx->dummy_ubuf->ubuf = -1UL;
if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
goto err;
ctx->flags = p->flags;
init_waitqueue_head(&ctx->sqo_sq_wait);
INIT_LIST_HEAD(&ctx->sqd_list);
INIT_LIST_HEAD(&ctx->cq_overflow_list);
INIT_LIST_HEAD(&ctx->io_buffers_cache);
INIT_LIST_HEAD(&ctx->apoll_cache);
init_completion(&ctx->ref_comp);
xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->cq_wait);
spin_lock_init(&ctx->completion_lock);
spin_lock_init(&ctx->timeout_lock);
INIT_WQ_LIST(&ctx->iopoll_list);
INIT_LIST_HEAD(&ctx->io_buffers_pages);
INIT_LIST_HEAD(&ctx->io_buffers_comp);
INIT_LIST_HEAD(&ctx->defer_list);
INIT_LIST_HEAD(&ctx->timeout_list);
INIT_LIST_HEAD(&ctx->ltimeout_list);
spin_lock_init(&ctx->rsrc_ref_lock);
INIT_LIST_HEAD(&ctx->rsrc_ref_list);
INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
init_llist_head(&ctx->rsrc_put_llist);
INIT_LIST_HEAD(&ctx->tctx_list);
ctx->submit_state.free_list.next = NULL;
INIT_WQ_LIST(&ctx->locked_free_list);
INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
return ctx;
err:
kfree(ctx->dummy_ubuf);
kfree(ctx->cancel_hash);
kfree(ctx->io_bl);
xa_destroy(&ctx->io_bl_xa);
kfree(ctx);
return NULL;
}
static void io_account_cq_overflow(struct io_ring_ctx *ctx)
{
struct io_rings *r = ctx->rings;
WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);
ctx->cq_extra--;
}
static bool req_need_defer(struct io_kiocb *req, u32 seq)
{
if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
struct io_ring_ctx *ctx = req->ctx;
return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail;
}
return false;
}
static inline bool io_req_ffs_set(struct io_kiocb *req)
{
return req->flags & REQ_F_FIXED_FILE;
}
static inline void io_req_track_inflight(struct io_kiocb *req)
{
if (!(req->flags & REQ_F_INFLIGHT)) {
req->flags |= REQ_F_INFLIGHT;
atomic_inc(&req->task->io_uring->inflight_tracked);
}
}
static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
{
if (WARN_ON_ONCE(!req->link))
return NULL;
req->flags &= ~REQ_F_ARM_LTIMEOUT;
req->flags |= REQ_F_LINK_TIMEOUT;
/* linked timeouts should have two refs once prep'ed */
io_req_set_refcount(req);
__io_req_set_refcount(req->link, 2);
return req->link;
}
static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
{
if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
return NULL;
return __io_prep_linked_timeout(req);
}
static noinline void __io_arm_ltimeout(struct io_kiocb *req)
{
io_queue_linked_timeout(__io_prep_linked_timeout(req));
}
static inline void io_arm_ltimeout(struct io_kiocb *req)
{
if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
__io_arm_ltimeout(req);
}
static void io_prep_async_work(struct io_kiocb *req)
{
const struct io_op_def *def = &io_op_defs[req->opcode];
struct io_ring_ctx *ctx = req->ctx;
if (!(req->flags & REQ_F_CREDS)) {
req->flags |= REQ_F_CREDS;
req->creds = get_current_cred();
}
req->work.list.next = NULL;
req->work.flags = 0;
req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
if (req->flags & REQ_F_FORCE_ASYNC)
req->work.flags |= IO_WQ_WORK_CONCURRENT;
if (req->flags & REQ_F_ISREG) {
if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
io_wq_hash_work(&req->work, file_inode(req->file));
} else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
if (def->unbound_nonreg_file)
req->work.flags |= IO_WQ_WORK_UNBOUND;
}
}
static void io_prep_async_link(struct io_kiocb *req)
{
struct io_kiocb *cur;
if (req->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = req->ctx;
spin_lock_irq(&ctx->timeout_lock);
io_for_each_link(cur, req)
io_prep_async_work(cur);
spin_unlock_irq(&ctx->timeout_lock);
} else {
io_for_each_link(cur, req)
io_prep_async_work(cur);
}
}
static inline void io_req_add_compl_list(struct io_kiocb *req)
{
struct io_submit_state *state = &req->ctx->submit_state;
if (!(req->flags & REQ_F_CQE_SKIP))
state->flush_cqes = true;
wq_list_add_tail(&req->comp_list, &state->compl_reqs);
}
static void io_queue_iowq(struct io_kiocb *req, bool *dont_use)
{
struct io_kiocb *link = io_prep_linked_timeout(req);
struct io_uring_task *tctx = req->task->io_uring;
BUG_ON(!tctx);
BUG_ON(!tctx->io_wq);
/* init ->work of the whole link before punting */
io_prep_async_link(req);
/*
* Not expected to happen, but if we do have a bug where this _can_
* happen, catch it here and ensure the request is marked as
* canceled. That will make io-wq go through the usual work cancel
* procedure rather than attempt to run this request (or create a new
* worker for it).
*/
if (WARN_ON_ONCE(!same_thread_group(req->task, current)))
req->work.flags |= IO_WQ_WORK_CANCEL;
trace_io_uring_queue_async_work(req->ctx, req, req->cqe.user_data,
req->opcode, req->flags, &req->work,
io_wq_is_hashed(&req->work));
io_wq_enqueue(tctx->io_wq, &req->work);
if (link)
io_queue_linked_timeout(link);
}
static void io_kill_timeout(struct io_kiocb *req, int status)
__must_hold(&req->ctx->completion_lock)
__must_hold(&req->ctx->timeout_lock)
{
struct io_timeout_data *io = req->async_data;
if (hrtimer_try_to_cancel(&io->timer) != -1) {
if (status)
req_set_fail(req);
atomic_set(&req->ctx->cq_timeouts,
atomic_read(&req->ctx->cq_timeouts) + 1);
list_del_init(&req->timeout.list);
io_req_tw_post_queue(req, status, 0);
}
}
static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
{
while (!list_empty(&ctx->defer_list)) {
struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
struct io_defer_entry, list);
if (req_need_defer(de->req, de->seq))
break;
list_del_init(&de->list);
io_req_task_queue(de->req);
kfree(de);
}
}
static __cold void io_flush_timeouts(struct io_ring_ctx *ctx)
__must_hold(&ctx->completion_lock)
{
u32 seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
struct io_kiocb *req, *tmp;
spin_lock_irq(&ctx->timeout_lock);
list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
u32 events_needed, events_got;
if (io_is_timeout_noseq(req))
break;
/*
* Since seq can easily wrap around over time, subtract
* the last seq at which timeouts were flushed before comparing.
* Assuming not more than 2^31-1 events have happened since,
* these subtractions won't have wrapped, so we can check if
* target is in [last_seq, current_seq] by comparing the two.
*/
events_needed = req->timeout.target_seq - ctx->cq_last_tm_flush;
events_got = seq - ctx->cq_last_tm_flush;
if (events_got < events_needed)
break;
io_kill_timeout(req, 0);
}
ctx->cq_last_tm_flush = seq;
spin_unlock_irq(&ctx->timeout_lock);
}
static inline void io_commit_cqring(struct io_ring_ctx *ctx)
{
/* order cqe stores with ring update */
smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
}
static void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
{
if (ctx->off_timeout_used || ctx->drain_active) {
spin_lock(&ctx->completion_lock);
if (ctx->off_timeout_used)
io_flush_timeouts(ctx);
if (ctx->drain_active)
io_queue_deferred(ctx);
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
}
if (ctx->has_evfd)
io_eventfd_signal(ctx);
}
static inline bool io_sqring_full(struct io_ring_ctx *ctx)
{
struct io_rings *r = ctx->rings;
return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries;
}
static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
{
return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
}
/*
* writes to the cq entry need to come after reading head; the
* control dependency is enough as we're using WRITE_ONCE to
* fill the cq entry
*/
static noinline struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
unsigned int shift = 0;
unsigned int free, queued, len;
if (ctx->flags & IORING_SETUP_CQE32)
shift = 1;
/* userspace may cheat modifying the tail, be safe and do min */
queued = min(__io_cqring_events(ctx), ctx->cq_entries);
free = ctx->cq_entries - queued;
/* we need a contiguous range, limit based on the current array offset */
len = min(free, ctx->cq_entries - off);
if (!len)
return NULL;
ctx->cached_cq_tail++;
ctx->cqe_cached = &rings->cqes[off];
ctx->cqe_sentinel = ctx->cqe_cached + len;
ctx->cqe_cached++;
return &rings->cqes[off << shift];
}
static inline struct io_uring_cqe *io_get_cqe(struct io_ring_ctx *ctx)
{
if (likely(ctx->cqe_cached < ctx->cqe_sentinel)) {
struct io_uring_cqe *cqe = ctx->cqe_cached;
if (ctx->flags & IORING_SETUP_CQE32) {
unsigned int off = ctx->cqe_cached - ctx->rings->cqes;
cqe += off;
}
ctx->cached_cq_tail++;
ctx->cqe_cached++;
return cqe;
}
return __io_get_cqe(ctx);
}
static void io_eventfd_signal(struct io_ring_ctx *ctx)
{
struct io_ev_fd *ev_fd;
rcu_read_lock();
/*
* rcu_dereference ctx->io_ev_fd once and use it for both for checking
* and eventfd_signal
*/
ev_fd = rcu_dereference(ctx->io_ev_fd);
/*
* Check again if ev_fd exists incase an io_eventfd_unregister call
* completed between the NULL check of ctx->io_ev_fd at the start of
* the function and rcu_read_lock.
*/
if (unlikely(!ev_fd))
goto out;
if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
goto out;
if (!ev_fd->eventfd_async || io_wq_current_is_worker())
eventfd_signal(ev_fd->cq_ev_fd, 1);
out:
rcu_read_unlock();
}
static inline void io_cqring_wake(struct io_ring_ctx *ctx)
{
/*
* wake_up_all() may seem excessive, but io_wake_function() and
* io_should_wake() handle the termination of the loop and only
* wake as many waiters as we need to.
*/
if (wq_has_sleeper(&ctx->cq_wait))
wake_up_all(&ctx->cq_wait);
}
/*
* This should only get called when at least one event has been posted.
* Some applications rely on the eventfd notification count only changing
* IFF a new CQE has been added to the CQ ring. There's no depedency on
* 1:1 relationship between how many times this function is called (and
* hence the eventfd count) and number of CQEs posted to the CQ ring.
*/
static inline void io_cqring_ev_posted(struct io_ring_ctx *ctx)
{
if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
ctx->has_evfd))
__io_commit_cqring_flush(ctx);
io_cqring_wake(ctx);
}
static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
{
if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
ctx->has_evfd))
__io_commit_cqring_flush(ctx);
if (ctx->flags & IORING_SETUP_SQPOLL)
io_cqring_wake(ctx);
}
/* Returns true if there are no backlogged entries after the flush */
static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
{
bool all_flushed, posted;
size_t cqe_size = sizeof(struct io_uring_cqe);
if (!force && __io_cqring_events(ctx) == ctx->cq_entries)
return false;
if (ctx->flags & IORING_SETUP_CQE32)
cqe_size <<= 1;
posted = false;
spin_lock(&ctx->completion_lock);
while (!list_empty(&ctx->cq_overflow_list)) {
struct io_uring_cqe *cqe = io_get_cqe(ctx);
struct io_overflow_cqe *ocqe;
if (!cqe && !force)
break;
ocqe = list_first_entry(&ctx->cq_overflow_list,
struct io_overflow_cqe, list);
if (cqe)
memcpy(cqe, &ocqe->cqe, cqe_size);
else
io_account_cq_overflow(ctx);
posted = true;
list_del(&ocqe->list);
kfree(ocqe);
}
all_flushed = list_empty(&ctx->cq_overflow_list);
if (all_flushed) {
clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
}
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
if (posted)
io_cqring_ev_posted(ctx);
return all_flushed;
}
static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx)
{
bool ret = true;
if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
/* iopoll syncs against uring_lock, not completion_lock */
if (ctx->flags & IORING_SETUP_IOPOLL)
mutex_lock(&ctx->uring_lock);
ret = __io_cqring_overflow_flush(ctx, false);
if (ctx->flags & IORING_SETUP_IOPOLL)
mutex_unlock(&ctx->uring_lock);
}
return ret;
}
static void __io_put_task(struct task_struct *task, int nr)
{
struct io_uring_task *tctx = task->io_uring;
percpu_counter_sub(&tctx->inflight, nr);
if (unlikely(atomic_read(&tctx->in_idle)))
wake_up(&tctx->wait);
put_task_struct_many(task, nr);
}
/* must to be called somewhat shortly after putting a request */
static inline void io_put_task(struct task_struct *task, int nr)
{
if (likely(task == current))
task->io_uring->cached_refs += nr;
else
__io_put_task(task, nr);
}
static void io_task_refs_refill(struct io_uring_task *tctx)
{
unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;
percpu_counter_add(&tctx->inflight, refill);
refcount_add(refill, &current->usage);
tctx->cached_refs += refill;
}
static inline void io_get_task_refs(int nr)
{
struct io_uring_task *tctx = current->io_uring;
tctx->cached_refs -= nr;
if (unlikely(tctx->cached_refs < 0))
io_task_refs_refill(tctx);
}
static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
{
struct io_uring_task *tctx = task->io_uring;
unsigned int refs = tctx->cached_refs;
if (refs) {
tctx->cached_refs = 0;
percpu_counter_sub(&tctx->inflight, refs);
put_task_struct_many(task, refs);
}
}
static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
s32 res, u32 cflags, u64 extra1,
u64 extra2)
{
struct io_overflow_cqe *ocqe;
size_t ocq_size = sizeof(struct io_overflow_cqe);
bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);
if (is_cqe32)
ocq_size += sizeof(struct io_uring_cqe);
ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT);
trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);
if (!ocqe) {
/*
* If we're in ring overflow flush mode, or in task cancel mode,
* or cannot allocate an overflow entry, then we need to drop it
* on the floor.
*/
io_account_cq_overflow(ctx);
set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
return false;
}
if (list_empty(&ctx->cq_overflow_list)) {
set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
}
ocqe->cqe.user_data = user_data;
ocqe->cqe.res = res;
ocqe->cqe.flags = cflags;
if (is_cqe32) {
ocqe->cqe.big_cqe[0] = extra1;
ocqe->cqe.big_cqe[1] = extra2;
}
list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
return true;
}
static inline bool __io_fill_cqe_req(struct io_ring_ctx *ctx,
struct io_kiocb *req)
{
struct io_uring_cqe *cqe;
if (!(ctx->flags & IORING_SETUP_CQE32)) {
trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
req->cqe.res, req->cqe.flags, 0, 0);
/*
* If we can't get a cq entry, userspace overflowed the
* submission (by quite a lot). Increment the overflow count in
* the ring.
*/
cqe = io_get_cqe(ctx);
if (likely(cqe)) {
memcpy(cqe, &req->cqe, sizeof(*cqe));
return true;
}
return io_cqring_event_overflow(ctx, req->cqe.user_data,
req->cqe.res, req->cqe.flags,
0, 0);
} else {
u64 extra1 = 0, extra2 = 0;
if (req->flags & REQ_F_CQE32_INIT) {
extra1 = req->extra1;
extra2 = req->extra2;
}
trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
req->cqe.res, req->cqe.flags, extra1, extra2);
/*
* If we can't get a cq entry, userspace overflowed the
* submission (by quite a lot). Increment the overflow count in
* the ring.
*/
cqe = io_get_cqe(ctx);
if (likely(cqe)) {
memcpy(cqe, &req->cqe, sizeof(struct io_uring_cqe));
WRITE_ONCE(cqe->big_cqe[0], extra1);
WRITE_ONCE(cqe->big_cqe[1], extra2);
return true;
}
return io_cqring_event_overflow(ctx, req->cqe.user_data,
req->cqe.res, req->cqe.flags,
extra1, extra2);
}
}
static noinline bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data,
s32 res, u32 cflags)
{
struct io_uring_cqe *cqe;
ctx->cq_extra++;
trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0);
/*
* If we can't get a cq entry, userspace overflowed the
* submission (by quite a lot). Increment the overflow count in
* the ring.
*/
cqe = io_get_cqe(ctx);
if (likely(cqe)) {
WRITE_ONCE(cqe->user_data, user_data);
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, cflags);
if (ctx->flags & IORING_SETUP_CQE32) {
WRITE_ONCE(cqe->big_cqe[0], 0);
WRITE_ONCE(cqe->big_cqe[1], 0);
}
return true;
}
return io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);
}
static void __io_req_complete_put(struct io_kiocb *req)
{
/*
* If we're the last reference to this request, add to our locked
* free_list cache.
*/
if (req_ref_put_and_test(req)) {
struct io_ring_ctx *ctx = req->ctx;
if (req->flags & IO_REQ_LINK_FLAGS) {
if (req->flags & IO_DISARM_MASK)
io_disarm_next(req);
if (req->link) {
io_req_task_queue(req->link);
req->link = NULL;
}
}
io_req_put_rsrc(req);
/*
* Selected buffer deallocation in io_clean_op() assumes that
* we don't hold ->completion_lock. Clean them here to avoid
* deadlocks.
*/
io_put_kbuf_comp(req);
io_dismantle_req(req);
io_put_task(req->task, 1);
wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
ctx->locked_free_nr++;
}
}
static void __io_req_complete_post(struct io_kiocb *req, s32 res,
u32 cflags)
{
if (!(req->flags & REQ_F_CQE_SKIP)) {
req->cqe.res = res;
req->cqe.flags = cflags;
__io_fill_cqe_req(req->ctx, req);
}
__io_req_complete_put(req);
}
static void io_req_complete_post(struct io_kiocb *req, s32 res, u32 cflags)
{
struct io_ring_ctx *ctx = req->ctx;
spin_lock(&ctx->completion_lock);
__io_req_complete_post(req, res, cflags);
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
io_cqring_ev_posted(ctx);
}
static inline void io_req_complete_state(struct io_kiocb *req, s32 res,
u32 cflags)
{
req->cqe.res = res;
req->cqe.flags = cflags;
req->flags |= REQ_F_COMPLETE_INLINE;
}
static inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags,
s32 res, u32 cflags)
{
if (issue_flags & IO_URING_F_COMPLETE_DEFER)
io_req_complete_state(req, res, cflags);
else
io_req_complete_post(req, res, cflags);
}
static inline void io_req_complete(struct io_kiocb *req, s32 res)
{
if (res < 0)
req_set_fail(req);
__io_req_complete(req, 0, res, 0);
}
static void io_req_complete_failed(struct io_kiocb *req, s32 res)
{
req_set_fail(req);
io_req_complete_post(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
}
/*
* Don't initialise the fields below on every allocation, but do that in
* advance and keep them valid across allocations.
*/
static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
req->ctx = ctx;
req->link = NULL;
req->async_data = NULL;
/* not necessary, but safer to zero */
req->cqe.res = 0;
}
static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
struct io_submit_state *state)
{
spin_lock(&ctx->completion_lock);
wq_list_splice(&ctx->locked_free_list, &state->free_list);
ctx->locked_free_nr = 0;
spin_unlock(&ctx->completion_lock);
}
static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
{
return !ctx->submit_state.free_list.next;
}
/*
* A request might get retired back into the request caches even before opcode
* handlers and io_issue_sqe() are done with it, e.g. inline completion path.
* Because of that, io_alloc_req() should be called only under ->uring_lock
* and with extra caution to not get a request that is still worked on.
*/
static __cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
void *reqs[IO_REQ_ALLOC_BATCH];
int ret, i;
/*
* If we have more than a batch's worth of requests in our IRQ side
* locked cache, grab the lock and move them over to our submission
* side cache.
*/
if (data_race(ctx->locked_free_nr) > IO_COMPL_BATCH) {
io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
if (!io_req_cache_empty(ctx))
return true;
}
ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);
/*
* Bulk alloc is all-or-nothing. If we fail to get a batch,
* retry single alloc to be on the safe side.
*/
if (unlikely(ret <= 0)) {
reqs[0] = kmem_cache_alloc(req_cachep, gfp);
if (!reqs[0])
return false;
ret = 1;
}
percpu_ref_get_many(&ctx->refs, ret);
for (i = 0; i < ret; i++) {
struct io_kiocb *req = reqs[i];
io_preinit_req(req, ctx);
io_req_add_to_cache(req, ctx);
}
return true;
}
static inline bool io_alloc_req_refill(struct io_ring_ctx *ctx)
{
if (unlikely(io_req_cache_empty(ctx)))
return __io_alloc_req_refill(ctx);
return true;
}
static inline struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
{
struct io_wq_work_node *node;
node = wq_stack_extract(&ctx->submit_state.free_list);
return container_of(node, struct io_kiocb, comp_list);
}
static inline void io_put_file(struct file *file)
{
if (file)
fput(file);
}
static inline void io_dismantle_req(struct io_kiocb *req)
{
unsigned int flags = req->flags;
if (unlikely(flags & IO_REQ_CLEAN_FLAGS))
io_clean_op(req);
if (!(flags & REQ_F_FIXED_FILE))
io_put_file(req->file);
}
static __cold void io_free_req(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
io_req_put_rsrc(req);
io_dismantle_req(req);
io_put_task(req->task, 1);
spin_lock(&ctx->completion_lock);
wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
ctx->locked_free_nr++;
spin_unlock(&ctx->completion_lock);
}
static inline void io_remove_next_linked(struct io_kiocb *req)
{
struct io_kiocb *nxt = req->link;
req->link = nxt->link;
nxt->link = NULL;
}
static struct io_kiocb *io_disarm_linked_timeout(struct io_kiocb *req)
__must_hold(&req->ctx->completion_lock)
__must_hold(&req->ctx->timeout_lock)
{
struct io_kiocb *link = req->link;
if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
struct io_timeout_data *io = link->async_data;
io_remove_next_linked(req);
link->timeout.head = NULL;
if (hrtimer_try_to_cancel(&io->timer) != -1) {
list_del(&link->timeout.list);
return link;
}
}
return NULL;
}
static void io_fail_links(struct io_kiocb *req)
__must_hold(&req->ctx->completion_lock)
{
struct io_kiocb *nxt, *link = req->link;
bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES;
req->link = NULL;
while (link) {
long res = -ECANCELED;
if (link->flags & REQ_F_FAIL)
res = link->cqe.res;
nxt = link->link;
link->link = NULL;
trace_io_uring_fail_link(req->ctx, req, req->cqe.user_data,
req->opcode, link);
if (ignore_cqes)
link->flags |= REQ_F_CQE_SKIP;
else
link->flags &= ~REQ_F_CQE_SKIP;
__io_req_complete_post(link, res, 0);
link = nxt;
}
}
static bool io_disarm_next(struct io_kiocb *req)
__must_hold(&req->ctx->completion_lock)
{
struct io_kiocb *link = NULL;
bool posted = false;
if (req->flags & REQ_F_ARM_LTIMEOUT) {
link = req->link;
req->flags &= ~REQ_F_ARM_LTIMEOUT;
if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
io_remove_next_linked(req);
io_req_tw_post_queue(link, -ECANCELED, 0);
posted = true;
}
} else if (req->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = req->ctx;
spin_lock_irq(&ctx->timeout_lock);
link = io_disarm_linked_timeout(req);
spin_unlock_irq(&ctx->timeout_lock);
if (link) {
posted = true;
io_req_tw_post_queue(link, -ECANCELED, 0);
}
}
if (unlikely((req->flags & REQ_F_FAIL) &&
!(req->flags & REQ_F_HARDLINK))) {
posted |= (req->link != NULL);
io_fail_links(req);
}
return posted;
}
static void __io_req_find_next_prep(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
bool posted;
spin_lock(&ctx->completion_lock);
posted = io_disarm_next(req);
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
if (posted)
io_cqring_ev_posted(ctx);
}
static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
{
struct io_kiocb *nxt;
/*
* If LINK is set, we have dependent requests in this chain. If we
* didn't fail this request, queue the first one up, moving any other
* dependencies to the next request. In case of failure, fail the rest
* of the chain.
*/
if (unlikely(req->flags & IO_DISARM_MASK))
__io_req_find_next_prep(req);
nxt = req->link;
req->link = NULL;
return nxt;
}
static void ctx_flush_and_put(struct io_ring_ctx *ctx, bool *locked)
{
if (!ctx)
return;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
if (*locked) {
io_submit_flush_completions(ctx);
mutex_unlock(&ctx->uring_lock);
*locked = false;
}
percpu_ref_put(&ctx->refs);
}
static inline void ctx_commit_and_unlock(struct io_ring_ctx *ctx)
{
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
io_cqring_ev_posted(ctx);
}
static void handle_prev_tw_list(struct io_wq_work_node *node,
struct io_ring_ctx **ctx, bool *uring_locked)
{
if (*ctx && !*uring_locked)
spin_lock(&(*ctx)->completion_lock);
do {
struct io_wq_work_node *next = node->next;
struct io_kiocb *req = container_of(node, struct io_kiocb,
io_task_work.node);
prefetch(container_of(next, struct io_kiocb, io_task_work.node));
if (req->ctx != *ctx) {
if (unlikely(!*uring_locked && *ctx))
ctx_commit_and_unlock(*ctx);
ctx_flush_and_put(*ctx, uring_locked);
*ctx = req->ctx;
/* if not contended, grab and improve batching */
*uring_locked = mutex_trylock(&(*ctx)->uring_lock);
percpu_ref_get(&(*ctx)->refs);
if (unlikely(!*uring_locked))
spin_lock(&(*ctx)->completion_lock);
}
if (likely(*uring_locked))
req->io_task_work.func(req, uring_locked);
else
__io_req_complete_post(req, req->cqe.res,
io_put_kbuf_comp(req));
node = next;
} while (node);
if (unlikely(!*uring_locked))
ctx_commit_and_unlock(*ctx);
}
static void handle_tw_list(struct io_wq_work_node *node,
struct io_ring_ctx **ctx, bool *locked)
{
do {
struct io_wq_work_node *next = node->next;
struct io_kiocb *req = container_of(node, struct io_kiocb,
io_task_work.node);
prefetch(container_of(next, struct io_kiocb, io_task_work.node));
if (req->ctx != *ctx) {
ctx_flush_and_put(*ctx, locked);
*ctx = req->ctx;
/* if not contended, grab and improve batching */
*locked = mutex_trylock(&(*ctx)->uring_lock);
percpu_ref_get(&(*ctx)->refs);
}
req->io_task_work.func(req, locked);
node = next;
} while (node);
}
static void tctx_task_work(struct callback_head *cb)
{
bool uring_locked = false;
struct io_ring_ctx *ctx = NULL;
struct io_uring_task *tctx = container_of(cb, struct io_uring_task,
task_work);
while (1) {
struct io_wq_work_node *node1, *node2;
spin_lock_irq(&tctx->task_lock);
node1 = tctx->prio_task_list.first;
node2 = tctx->task_list.first;
INIT_WQ_LIST(&tctx->task_list);
INIT_WQ_LIST(&tctx->prio_task_list);
if (!node2 && !node1)
tctx->task_running = false;
spin_unlock_irq(&tctx->task_lock);
if (!node2 && !node1)
break;
if (node1)
handle_prev_tw_list(node1, &ctx, &uring_locked);
if (node2)
handle_tw_list(node2, &ctx, &uring_locked);
cond_resched();
if (data_race(!tctx->task_list.first) &&
data_race(!tctx->prio_task_list.first) && uring_locked)
io_submit_flush_completions(ctx);
}
ctx_flush_and_put(ctx, &uring_locked);
/* relaxed read is enough as only the task itself sets ->in_idle */
if (unlikely(atomic_read(&tctx->in_idle)))
io_uring_drop_tctx_refs(current);
}
static void __io_req_task_work_add(struct io_kiocb *req,
struct io_uring_task *tctx,
struct io_wq_work_list *list)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_wq_work_node *node;
unsigned long flags;
bool running;
spin_lock_irqsave(&tctx->task_lock, flags);
wq_list_add_tail(&req->io_task_work.node, list);
running = tctx->task_running;
if (!running)
tctx->task_running = true;
spin_unlock_irqrestore(&tctx->task_lock, flags);
/* task_work already pending, we're done */
if (running)
return;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))
return;
spin_lock_irqsave(&tctx->task_lock, flags);
tctx->task_running = false;
node = wq_list_merge(&tctx->prio_task_list, &tctx->task_list);
spin_unlock_irqrestore(&tctx->task_lock, flags);
while (node) {
req = container_of(node, struct io_kiocb, io_task_work.node);
node = node->next;
if (llist_add(&req->io_task_work.fallback_node,
&req->ctx->fallback_llist))
schedule_delayed_work(&req->ctx->fallback_work, 1);
}
}
static void io_req_task_work_add(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->task->io_uring;
__io_req_task_work_add(req, tctx, &tctx->task_list);
}
static void io_req_task_prio_work_add(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->task->io_uring;
if (req->ctx->flags & IORING_SETUP_SQPOLL)
__io_req_task_work_add(req, tctx, &tctx->prio_task_list);
else
__io_req_task_work_add(req, tctx, &tctx->task_list);
}
static void io_req_tw_post(struct io_kiocb *req, bool *locked)
{
io_req_complete_post(req, req->cqe.res, req->cqe.flags);
}
static void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags)
{
req->cqe.res = res;
req->cqe.flags = cflags;
req->io_task_work.func = io_req_tw_post;
io_req_task_work_add(req);
}
static void io_req_task_cancel(struct io_kiocb *req, bool *locked)
{
/* not needed for normal modes, but SQPOLL depends on it */
io_tw_lock(req->ctx, locked);
io_req_complete_failed(req, req->cqe.res);
}
static void io_req_task_submit(struct io_kiocb *req, bool *locked)
{
io_tw_lock(req->ctx, locked);
/* req->task == current here, checking PF_EXITING is safe */
if (likely(!(req->task->flags & PF_EXITING)))
io_queue_sqe(req);
else
io_req_complete_failed(req, -EFAULT);
}
static void io_req_task_queue_fail(struct io_kiocb *req, int ret)
{
req->cqe.res = ret;
req->io_task_work.func = io_req_task_cancel;
io_req_task_work_add(req);
}
static void io_req_task_queue(struct io_kiocb *req)
{
req->io_task_work.func = io_req_task_submit;
io_req_task_work_add(req);
}
static void io_req_task_queue_reissue(struct io_kiocb *req)
{
req->io_task_work.func = io_queue_iowq;
io_req_task_work_add(req);
}
static void io_queue_next(struct io_kiocb *req)
{
struct io_kiocb *nxt = io_req_find_next(req);
if (nxt)
io_req_task_queue(nxt);
}
static void io_free_batch_list(struct io_ring_ctx *ctx,
struct io_wq_work_node *node)
__must_hold(&ctx->uring_lock)
{
struct task_struct *task = NULL;
int task_refs = 0;
do {
struct io_kiocb *req = container_of(node, struct io_kiocb,
comp_list);
if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {
if (req->flags & REQ_F_REFCOUNT) {
node = req->comp_list.next;
if (!req_ref_put_and_test(req))
continue;
}
if ((req->flags & REQ_F_POLLED) && req->apoll) {
struct async_poll *apoll = req->apoll;
if (apoll->double_poll)
kfree(apoll->double_poll);
list_add(&apoll->poll.wait.entry,
&ctx->apoll_cache);
req->flags &= ~REQ_F_POLLED;
}
if (req->flags & IO_REQ_LINK_FLAGS)
io_queue_next(req);
if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
io_clean_op(req);
}
if (!(req->flags & REQ_F_FIXED_FILE))
io_put_file(req->file);
io_req_put_rsrc_locked(req, ctx);
if (req->task != task) {
if (task)
io_put_task(task, task_refs);
task = req->task;
task_refs = 0;
}
task_refs++;
node = req->comp_list.next;
io_req_add_to_cache(req, ctx);
} while (node);
if (task)
io_put_task(task, task_refs);
}
static void __io_submit_flush_completions(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
struct io_wq_work_node *node, *prev;
struct io_submit_state *state = &ctx->submit_state;
if (state->flush_cqes) {
spin_lock(&ctx->completion_lock);
wq_list_for_each(node, prev, &state->compl_reqs) {
struct io_kiocb *req = container_of(node, struct io_kiocb,
comp_list);
if (!(req->flags & REQ_F_CQE_SKIP))
__io_fill_cqe_req(ctx, req);
}
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
io_cqring_ev_posted(ctx);
state->flush_cqes = false;
}
io_free_batch_list(ctx, state->compl_reqs.first);
INIT_WQ_LIST(&state->compl_reqs);
}
/*
* Drop reference to request, return next in chain (if there is one) if this
* was the last reference to this request.
*/
static inline struct io_kiocb *io_put_req_find_next(struct io_kiocb *req)
{
struct io_kiocb *nxt = NULL;
if (req_ref_put_and_test(req)) {
if (unlikely(req->flags & IO_REQ_LINK_FLAGS))
nxt = io_req_find_next(req);
io_free_req(req);
}
return nxt;
}
static inline void io_put_req(struct io_kiocb *req)
{
if (req_ref_put_and_test(req)) {
io_queue_next(req);
io_free_req(req);
}
}
static unsigned io_cqring_events(struct io_ring_ctx *ctx)
{
/* See comment at the top of this file */
smp_rmb();
return __io_cqring_events(ctx);
}
static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
/* make sure SQ entry isn't read before tail */
return<