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Commit f3b44f92 authored by Jens Axboe's avatar Jens Axboe
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io_uring: move read/write related opcodes to its own file 

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c98817e6
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Showing with 1263 additions and 1231 deletions
io_uring/Makefile
View file @ f3b44f92
......@@ -7,5 +7,5 @@ obj-$(CONFIG_IO_URING) += io_uring.o xattr.o nop.o fs.o splice.o \
openclose.o uring_cmd.o epoll.o \
statx.o net.o msg_ring.o timeout.o \
sqpoll.o fdinfo.o tctx.o poll.o \
cancel.o kbuf.o rsrc.o
cancel.o kbuf.o rsrc.o rw.o
obj-$(CONFIG_IO_WQ) += io-wq.o
io_uring/io_uring.c
View file @ f3b44f92
......@@ -43,7 +43,6 @@
#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>
......@@ -57,7 +56,6 @@
#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>
......@@ -67,13 +65,10 @@
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
#include <linux/sizes.h>
#include <linux/highmem.h>
#include <linux/fsnotify.h>
#include <linux/fadvise.h>
#include <linux/eventpoll.h>
#include <linux/task_work.h>
#include <linux/pagemap.h>
#include <linux/io_uring.h>
#include <linux/audit.h>
#include <linux/security.h>
......@@ -110,6 +105,7 @@
#include "timeout.h"
#include "poll.h"
#include "cancel.h"
#include "rw.h"
#define IORING_MAX_ENTRIES 32768
#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
......@@ -136,31 +132,6 @@
#define IO_REQ_CACHE_SIZE 32
#define IO_REQ_ALLOC_BATCH 8
/*
* First field must be the file pointer in all the
* iocb unions! See also 'struct kiocb' in <linux/fs.h>
*/
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_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;
};
enum {
IO_CHECK_CQ_OVERFLOW_BIT,
IO_CHECK_CQ_DROPPED_BIT,
......@@ -184,9 +155,7 @@ static void io_dismantle_req(struct io_kiocb *req);
static void io_clean_op(struct io_kiocb *req);
static void io_queue_sqe(struct io_kiocb *req);
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 void io_eventfd_signal(struct io_ring_ctx *ctx);
......@@ -393,11 +362,6 @@ static bool req_need_defer(struct io_kiocb *req, u32 seq)
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)) {
......@@ -489,7 +453,7 @@ static inline void io_req_add_compl_list(struct io_kiocb *req)
wq_list_add_tail(&req->comp_list, &state->compl_reqs);
}
static void io_queue_iowq(struct io_kiocb *req, bool *dont_use)
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;
......@@ -532,7 +496,7 @@ static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
}
}
static void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
{
if (ctx->off_timeout_used || ctx->drain_active) {
spin_lock(&ctx->completion_lock);
......@@ -547,60 +511,6 @@ static void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
io_eventfd_signal(ctx);
}
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;
......@@ -628,17 +538,6 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx)
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
......@@ -655,16 +554,6 @@ void io_cqring_ev_posted(struct io_ring_ctx *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)
{
......@@ -775,9 +664,8 @@ static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
}
}
static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
s32 res, u32 cflags, u64 extra1,
u64 extra2)
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);
......@@ -814,59 +702,6 @@ static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
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);
}
}
bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
u32 cflags)
{
......@@ -1269,7 +1104,7 @@ void io_req_task_work_add(struct io_kiocb *req)
__io_req_task_work_add(req, tctx, &tctx->task_list);
}
static void io_req_task_prio_work_add(struct io_kiocb *req)
void io_req_task_prio_work_add(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->task->io_uring;
......@@ -1315,18 +1150,12 @@ void io_req_task_queue_fail(struct io_kiocb *req, int ret)
io_req_task_work_add(req);
}
static void io_req_task_queue(struct io_kiocb *req)
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);
}
void io_queue_next(struct io_kiocb *req)
{
struct io_kiocb *nxt = io_req_find_next(req);
......@@ -1335,8 +1164,7 @@ void io_queue_next(struct io_kiocb *req)
io_req_task_queue(nxt);
}
static void io_free_batch_list(struct io_ring_ctx *ctx,
struct io_wq_work_node *node)
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;
......@@ -1435,76 +1263,6 @@ static unsigned io_cqring_events(struct io_ring_ctx *ctx)
return __io_cqring_events(ctx);
}
int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
{
struct io_wq_work_node *pos, *start, *prev;
unsigned int poll_flags = BLK_POLL_NOSLEEP;
DEFINE_IO_COMP_BATCH(iob);
int nr_events = 0;
/*
* Only spin for completions if we don't have multiple devices hanging
* off our complete list.
*/
if (ctx->poll_multi_queue || force_nonspin)
poll_flags |= BLK_POLL_ONESHOT;
wq_list_for_each(pos, start, &ctx->iopoll_list) {
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
struct io_rw *rw = io_kiocb_to_cmd(req);
int ret;
/*
* Move completed and retryable entries to our local lists.
* If we find a request that requires polling, break out
* and complete those lists first, if we have entries there.
*/
if (READ_ONCE(req->iopoll_completed))
break;
ret = rw->kiocb.ki_filp->f_op->iopoll(&rw->kiocb, &iob, poll_flags);
if (unlikely(ret < 0))
return ret;
else if (ret)
poll_flags |= BLK_POLL_ONESHOT;
/* iopoll may have completed current req */
if (!rq_list_empty(iob.req_list) ||
READ_ONCE(req->iopoll_completed))
break;
}
if (!rq_list_empty(iob.req_list))
iob.complete(&iob);
else if (!pos)
return 0;
prev = start;
wq_list_for_each_resume(pos, prev) {
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
/* order with io_complete_rw_iopoll(), e.g. ->result updates */
if (!smp_load_acquire(&req->iopoll_completed))
break;
nr_events++;
if (unlikely(req->flags & REQ_F_CQE_SKIP))
continue;
req->cqe.flags = io_put_kbuf(req, 0);
__io_fill_cqe_req(req->ctx, req);
}
if (unlikely(!nr_events))
return 0;
io_commit_cqring(ctx);
io_cqring_ev_posted_iopoll(ctx);
pos = start ? start->next : ctx->iopoll_list.first;
wq_list_cut(&ctx->iopoll_list, prev, start);
io_free_batch_list(ctx, pos);
return nr_events;
}
/*
* We can't just wait for polled events to come to us, we have to actively
* find and complete them.
......@@ -1589,90 +1347,6 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
return ret;
}
static void kiocb_end_write(struct io_kiocb *req)
{
/*
* Tell lockdep we inherited freeze protection from submission
* thread.
*/
if (req->flags & REQ_F_ISREG) {
struct super_block *sb = file_inode(req->file)->i_sb;
__sb_writers_acquired(sb, SB_FREEZE_WRITE);
sb_end_write(sb);
}
}
#ifdef CONFIG_BLOCK
static bool io_resubmit_prep(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
if (!req_has_async_data(req))
return !io_req_prep_async(req);
iov_iter_restore(&io->s.iter, &io->s.iter_state);
return true;
}
static bool io_rw_should_reissue(struct io_kiocb *req)
{
umode_t mode = file_inode(req->file)->i_mode;
struct io_ring_ctx *ctx = req->ctx;
if (!S_ISBLK(mode) && !S_ISREG(mode))
return false;
if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
!(ctx->flags & IORING_SETUP_IOPOLL)))
return false;
/*
* If ref is dying, we might be running poll reap from the exit work.
* Don't attempt to reissue from that path, just let it fail with
* -EAGAIN.
*/
if (percpu_ref_is_dying(&ctx->refs))
return false;
/*
* Play it safe and assume not safe to re-import and reissue if we're
* not in the original thread group (or in task context).
*/
if (!same_thread_group(req->task, current) || !in_task())
return false;
return true;
}
#else
static bool io_resubmit_prep(struct io_kiocb *req)
{
return false;
}
static bool io_rw_should_reissue(struct io_kiocb *req)
{
return false;
}
#endif
static bool __io_complete_rw_common(struct io_kiocb *req, long res)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
if (rw->kiocb.ki_flags & IOCB_WRITE) {
kiocb_end_write(req);
fsnotify_modify(req->file);
} else {
fsnotify_access(req->file);
}
if (unlikely(res != req->cqe.res)) {
if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
io_rw_should_reissue(req)) {
req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
return true;
}
req_set_fail(req);
req->cqe.res = res;
}
return false;
}
inline void io_req_task_complete(struct io_kiocb *req, bool *locked)
{
if (*locked) {
......@@ -1685,46 +1359,6 @@ inline void io_req_task_complete(struct io_kiocb *req, bool *locked)
}
}
static void __io_complete_rw(struct io_kiocb *req, long res,
unsigned int issue_flags)
{
if (__io_complete_rw_common(req, res))
return;
io_req_set_res(req, req->cqe.res, io_put_kbuf(req, issue_flags));
__io_req_complete(req, issue_flags);
}
static void io_complete_rw(struct kiocb *kiocb, long res)
{
struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
struct io_kiocb *req = cmd_to_io_kiocb(rw);
if (__io_complete_rw_common(req, res))
return;
io_req_set_res(req, res, 0);
req->io_task_work.func = io_req_task_complete;
io_req_task_prio_work_add(req);
}
static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
{
struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
struct io_kiocb *req = cmd_to_io_kiocb(rw);
if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
if (unlikely(res != req->cqe.res)) {
if (res == -EAGAIN && io_rw_should_reissue(req)) {
req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
return;
}
req->cqe.res = res;
}
/* order with io_iopoll_complete() checking ->iopoll_completed */
smp_store_release(&req->iopoll_completed, 1);
}
/*
* After the iocb has been issued, it's safe to be found on the poll list.
* Adding the kiocb to the list AFTER submission ensures that we don't
......@@ -1833,879 +1467,24 @@ unsigned int io_file_get_flags(struct file *file)
return res;
}
static inline bool io_file_supports_nowait(struct io_kiocb *req)
{
return req->flags & REQ_F_SUPPORT_NOWAIT;
}
static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
unsigned ioprio;
int ret;
rw->kiocb.ki_pos = READ_ONCE(sqe->off);
/* used for fixed read/write too - just read unconditionally */
req->buf_index = READ_ONCE(sqe->buf_index);
if (req->opcode == IORING_OP_READ_FIXED ||
req->opcode == IORING_OP_WRITE_FIXED) {
struct io_ring_ctx *ctx = req->ctx;
u16 index;
if (unlikely(req->buf_index >= ctx->nr_user_bufs))
return -EFAULT;
index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
req->imu = ctx->user_bufs[index];
io_req_set_rsrc_node(req, ctx, 0);
}
ioprio = READ_ONCE(sqe->ioprio);
if (ioprio) {
ret = ioprio_check_cap(ioprio);
if (ret)
return ret;
rw->kiocb.ki_ioprio = ioprio;
} else {
rw->kiocb.ki_ioprio = get_current_ioprio();
}
rw->addr = READ_ONCE(sqe->addr);
rw->len = READ_ONCE(sqe->len);
rw->flags = READ_ONCE(sqe->rw_flags);
return 0;
}
static void io_readv_writev_cleanup(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
kfree(io->free_iovec);
}
static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
{
switch (ret) {
case -EIOCBQUEUED:
break;
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/*
* We can't just restart the syscall, since previously
* submitted sqes may already be in progress. Just fail this
* IO with EINTR.
*/
ret = -EINTR;
fallthrough;
default:
kiocb->ki_complete(kiocb, ret);
}
}
static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
if (rw->kiocb.ki_pos != -1)
return &rw->kiocb.ki_pos;
if (!(req->file->f_mode & FMODE_STREAM)) {
req->flags |= REQ_F_CUR_POS;
rw->kiocb.ki_pos = req->file->f_pos;
return &rw->kiocb.ki_pos;
}
rw->kiocb.ki_pos = 0;
return NULL;
}
static void kiocb_done(struct io_kiocb *req, ssize_t ret,
unsigned int issue_flags)
bool io_alloc_async_data(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
struct io_rw *rw = io_kiocb_to_cmd(req);
/* add previously done IO, if any */
if (req_has_async_data(req) && io->bytes_done > 0) {
if (ret < 0)
ret = io->bytes_done;
else
ret += io->bytes_done;
}
if (req->flags & REQ_F_CUR_POS)
req->file->f_pos = rw->kiocb.ki_pos;
if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw))
__io_complete_rw(req, ret, issue_flags);
else
io_rw_done(&rw->kiocb, ret);
if (req->flags & REQ_F_REISSUE) {
req->flags &= ~REQ_F_REISSUE;
if (io_resubmit_prep(req))
io_req_task_queue_reissue(req);
else
io_req_task_queue_fail(req, ret);
}
}
static int __io_import_fixed(struct io_kiocb *req, int ddir,
struct iov_iter *iter, struct io_mapped_ubuf *imu)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
size_t len = rw->len;
u64 buf_end, buf_addr = rw->addr;
size_t offset;
if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
return -EFAULT;
/* not inside the mapped region */
if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
return -EFAULT;
/*
* May not be a start of buffer, set size appropriately
* and advance us to the beginning.
*/
offset = buf_addr - imu->ubuf;
iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
if (offset) {
/*
* Don't use iov_iter_advance() here, as it's really slow for
* using the latter parts of a big fixed buffer - it iterates
* over each segment manually. We can cheat a bit here, because
* we know that:
*
* 1) it's a BVEC iter, we set it up
* 2) all bvecs are PAGE_SIZE in size, except potentially the
* first and last bvec
*
* So just find our index, and adjust the iterator afterwards.
* If the offset is within the first bvec (or the whole first
* bvec, just use iov_iter_advance(). This makes it easier
* since we can just skip the first segment, which may not
* be PAGE_SIZE aligned.
*/
const struct bio_vec *bvec = imu->bvec;
if (offset <= bvec->bv_len) {
iov_iter_advance(iter, offset);
} else {
unsigned long seg_skip;
/* skip first vec */
offset -= bvec->bv_len;
seg_skip = 1 + (offset >> PAGE_SHIFT);
iter->bvec = bvec + seg_skip;
iter->nr_segs -= seg_skip;
iter->count -= bvec->bv_len + offset;
iter->iov_offset = offset & ~PAGE_MASK;
}
}
return 0;
}
static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter,
unsigned int issue_flags)
{
if (WARN_ON_ONCE(!req->imu))
return -EFAULT;
return __io_import_fixed(req, rw, iter, req->imu);
}
#ifdef CONFIG_COMPAT
static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct compat_iovec __user *uiov;
compat_ssize_t clen;
void __user *buf;
size_t len;
uiov = u64_to_user_ptr(rw->addr);
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(clen, &uiov->iov_len))
return -EFAULT;
if (clen < 0)
return -EINVAL;
len = clen;
buf = io_buffer_select(req, &len, issue_flags);
if (!buf)
return -ENOBUFS;
rw->addr = (unsigned long) buf;
iov[0].iov_base = buf;
rw->len = iov[0].iov_len = (compat_size_t) len;
return 0;
}
#endif
static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct iovec __user *uiov = u64_to_user_ptr(rw->addr);
void __user *buf;
ssize_t len;
if (copy_from_user(iov, uiov, sizeof(*uiov)))
return -EFAULT;
len = iov[0].iov_len;
if (len < 0)
return -EINVAL;
buf = io_buffer_select(req, &len, issue_flags);
if (!buf)
return -ENOBUFS;
rw->addr = (unsigned long) buf;
iov[0].iov_base = buf;
rw->len = iov[0].iov_len = len;
return 0;
}
static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) {
iov[0].iov_base = u64_to_user_ptr(rw->addr);
iov[0].iov_len = rw->len;
return 0;
}
if (rw->len != 1)
return -EINVAL;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
return io_compat_import(req, iov, issue_flags);
#endif
return __io_iov_buffer_select(req, iov, issue_flags);
}
static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req,
struct io_rw_state *s,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct iov_iter *iter = &s->iter;
u8 opcode = req->opcode;
struct iovec *iovec;
void __user *buf;
size_t sqe_len;
ssize_t ret;
if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
ret = io_import_fixed(req, ddir, iter, issue_flags);
if (ret)
return ERR_PTR(ret);
return NULL;
}
buf = u64_to_user_ptr(rw->addr);
sqe_len = rw->len;
if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
if (io_do_buffer_select(req)) {
buf = io_buffer_select(req, &sqe_len, issue_flags);
if (!buf)
return ERR_PTR(-ENOBUFS);
rw->addr = (unsigned long) buf;
rw->len = sqe_len;
}
ret = import_single_range(ddir, buf, sqe_len, s->fast_iov, iter);
if (ret)
return ERR_PTR(ret);
return NULL;
}
iovec = s->fast_iov;
if (req->flags & REQ_F_BUFFER_SELECT) {
ret = io_iov_buffer_select(req, iovec, issue_flags);
if (ret)
return ERR_PTR(ret);
iov_iter_init(iter, ddir, iovec, 1, iovec->iov_len);
return NULL;
}
ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
req->ctx->compat);
if (unlikely(ret < 0))
return ERR_PTR(ret);
return iovec;
}
static inline int io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct io_rw_state *s,
unsigned int issue_flags)
{
*iovec = __io_import_iovec(rw, req, s, issue_flags);
if (unlikely(IS_ERR(*iovec)))
return PTR_ERR(*iovec);
iov_iter_save_state(&s->iter, &s->iter_state);
return 0;
}
static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
{
return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
}
/*
* For files that don't have ->read_iter() and ->write_iter(), handle them
* by looping over ->read() or ->write() manually.
*/
static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
{
struct kiocb *kiocb = &rw->kiocb;
struct file *file = kiocb->ki_filp;
ssize_t ret = 0;
loff_t *ppos;
/*
* Don't support polled IO through this interface, and we can't
* support non-blocking either. For the latter, this just causes
* the kiocb to be handled from an async context.
*/
if (kiocb->ki_flags & IOCB_HIPRI)
return -EOPNOTSUPP;
if ((kiocb->ki_flags & IOCB_NOWAIT) &&
!(kiocb->ki_filp->f_flags & O_NONBLOCK))
return -EAGAIN;
ppos = io_kiocb_ppos(kiocb);
while (iov_iter_count(iter)) {
struct iovec iovec;
ssize_t nr;
if (!iov_iter_is_bvec(iter)) {
iovec = iov_iter_iovec(iter);
} else {
iovec.iov_base = u64_to_user_ptr(rw->addr);
iovec.iov_len = rw->len;
}
if (ddir == READ) {
nr = file->f_op->read(file, iovec.iov_base,
iovec.iov_len, ppos);
} else {
nr = file->f_op->write(file, iovec.iov_base,
iovec.iov_len, ppos);
}
if (nr < 0) {
if (!ret)
ret = nr;
break;
}
ret += nr;
if (!iov_iter_is_bvec(iter)) {
iov_iter_advance(iter, nr);
} else {
rw->addr += nr;
rw->len -= nr;
if (!rw->len)
break;
}
if (nr != iovec.iov_len)
break;
}
return ret;
}
static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
const struct iovec *fast_iov, struct iov_iter *iter)
{
struct io_async_rw *io = req->async_data;
memcpy(&io->s.iter, iter, sizeof(*iter));
io->free_iovec = iovec;
io->bytes_done = 0;
/* can only be fixed buffers, no need to do anything */
if (iov_iter_is_bvec(iter))
return;
if (!iovec) {
unsigned iov_off = 0;
io->s.iter.iov = io->s.fast_iov;
if (iter->iov != fast_iov) {
iov_off = iter->iov - fast_iov;
io->s.iter.iov += iov_off;
}
if (io->s.fast_iov != fast_iov)
memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off,
sizeof(struct iovec) * iter->nr_segs);
} else {
req->flags |= REQ_F_NEED_CLEANUP;
}
}
bool io_alloc_async_data(struct io_kiocb *req)
{
WARN_ON_ONCE(!io_op_defs[req->opcode].async_size);
req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL);
if (req->async_data) {
req->flags |= REQ_F_ASYNC_DATA;
return false;
WARN_ON_ONCE(!io_op_defs[req->opcode].async_size);
req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL);
if (req->async_data) {
req->flags |= REQ_F_ASYNC_DATA;
return false;
}
return true;
}
static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
struct io_rw_state *s, bool force)
{
if (!force && !io_op_defs[req->opcode].prep_async)
return 0;
if (!req_has_async_data(req)) {
struct io_async_rw *iorw;
if (io_alloc_async_data(req)) {
kfree(iovec);
return -ENOMEM;
}
io_req_map_rw(req, iovec, s->fast_iov, &s->iter);
iorw = req->async_data;
/* we've copied and mapped the iter, ensure state is saved */
iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state);
}
return 0;
}
static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
{
struct io_async_rw *iorw = req->async_data;
struct iovec *iov;
int ret;
/* submission path, ->uring_lock should already be taken */
ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
if (unlikely(ret < 0))
return ret;
iorw->bytes_done = 0;
iorw->free_iovec = iov;
if (iov)
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
static int io_readv_prep_async(struct io_kiocb *req)
{
return io_rw_prep_async(req, READ);
}
static int io_writev_prep_async(struct io_kiocb *req)
{
return io_rw_prep_async(req, WRITE);
}
/*
* This is our waitqueue callback handler, registered through __folio_lock_async()
* when we initially tried to do the IO with the iocb armed our waitqueue.
* This gets called when the page is unlocked, and we generally expect that to
* happen when the page IO is completed and the page is now uptodate. This will
* queue a task_work based retry of the operation, attempting to copy the data
* again. If the latter fails because the page was NOT uptodate, then we will
* do a thread based blocking retry of the operation. That's the unexpected
* slow path.
*/
static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
int sync, void *arg)
{
struct wait_page_queue *wpq;
struct io_kiocb *req = wait->private;
struct io_rw *rw = io_kiocb_to_cmd(req);
struct wait_page_key *key = arg;
wpq = container_of(wait, struct wait_page_queue, wait);
if (!wake_page_match(wpq, key))
return 0;
rw->kiocb.ki_flags &= ~IOCB_WAITQ;
list_del_init(&wait->entry);
io_req_task_queue(req);
return 1;
}
/*
* This controls whether a given IO request should be armed for async page
* based retry. If we return false here, the request is handed to the async
* worker threads for retry. If we're doing buffered reads on a regular file,
* we prepare a private wait_page_queue entry and retry the operation. This
* will either succeed because the page is now uptodate and unlocked, or it
* will register a callback when the page is unlocked at IO completion. Through
* that callback, io_uring uses task_work to setup a retry of the operation.
* That retry will attempt the buffered read again. The retry will generally
* succeed, or in rare cases where it fails, we then fall back to using the
* async worker threads for a blocking retry.
*/
static bool io_rw_should_retry(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
struct wait_page_queue *wait = &io->wpq;
struct io_rw *rw = io_kiocb_to_cmd(req);
struct kiocb *kiocb = &rw->kiocb;
/* never retry for NOWAIT, we just complete with -EAGAIN */
if (req->flags & REQ_F_NOWAIT)
return false;
/* Only for buffered IO */
if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
return false;
/*
* just use poll if we can, and don't attempt if the fs doesn't
* support callback based unlocks
*/
if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
return false;
wait->wait.func = io_async_buf_func;
wait->wait.private = req;
wait->wait.flags = 0;
INIT_LIST_HEAD(&wait->wait.entry);
kiocb->ki_flags |= IOCB_WAITQ;
kiocb->ki_flags &= ~IOCB_NOWAIT;
kiocb->ki_waitq = wait;
return true;
}
static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter)
{
struct file *file = rw->kiocb.ki_filp;
if (likely(file->f_op->read_iter))
return call_read_iter(file, &rw->kiocb, iter);
else if (file->f_op->read)
return loop_rw_iter(READ, rw, iter);
else
return -EINVAL;
}
static bool need_read_all(struct io_kiocb *req)
{
return req->flags & REQ_F_ISREG ||
S_ISBLK(file_inode(req->file)->i_mode);
}
static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct kiocb *kiocb = &rw->kiocb;
struct io_ring_ctx *ctx = req->ctx;
struct file *file = req->file;
int ret;
if (unlikely(!file || !(file->f_mode & mode)))
return -EBADF;
if (!io_req_ffs_set(req))
req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT;
kiocb->ki_flags = iocb_flags(file);
ret = kiocb_set_rw_flags(kiocb, rw->flags);
if (unlikely(ret))
return ret;
/*
* If the file is marked O_NONBLOCK, still allow retry for it if it
* supports async. Otherwise it's impossible to use O_NONBLOCK files
* reliably. If not, or it IOCB_NOWAIT is set, don't retry.
*/
if ((kiocb->ki_flags & IOCB_NOWAIT) ||
((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
req->flags |= REQ_F_NOWAIT;
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
return -EOPNOTSUPP;
kiocb->private = NULL;
kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE;
kiocb->ki_complete = io_complete_rw_iopoll;
req->iopoll_completed = 0;
} else {
if (kiocb->ki_flags & IOCB_HIPRI)
return -EINVAL;
kiocb->ki_complete = io_complete_rw;
}
return 0;
}
static int io_read(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct io_rw_state __s, *s = &__s;
struct iovec *iovec;
struct kiocb *kiocb = &rw->kiocb;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
struct io_async_rw *io;
ssize_t ret, ret2;
loff_t *ppos;
if (!req_has_async_data(req)) {
ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
} else {
io = req->async_data;
s = &io->s;
/*
* Safe and required to re-import if we're using provided
* buffers, as we dropped the selected one before retry.
*/
if (io_do_buffer_select(req)) {
ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
}
/*
* We come here from an earlier attempt, restore our state to
* match in case it doesn't. It's cheap enough that we don't
* need to make this conditional.
*/
iov_iter_restore(&s->iter, &s->iter_state);
iovec = NULL;
}
ret = io_rw_init_file(req, FMODE_READ);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
req->cqe.res = iov_iter_count(&s->iter);
if (force_nonblock) {
/* If the file doesn't support async, just async punt */
if (unlikely(!io_file_supports_nowait(req))) {
ret = io_setup_async_rw(req, iovec, s, true);
return ret ?: -EAGAIN;
}
kiocb->ki_flags |= IOCB_NOWAIT;
} else {
/* Ensure we clear previously set non-block flag */
kiocb->ki_flags &= ~IOCB_NOWAIT;
}
ppos = io_kiocb_update_pos(req);
ret = rw_verify_area(READ, req->file, ppos, req->cqe.res);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
ret = io_iter_do_read(rw, &s->iter);
if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
req->flags &= ~REQ_F_REISSUE;
/* if we can poll, just do that */
if (req->opcode == IORING_OP_READ && file_can_poll(req->file))
return -EAGAIN;
/* IOPOLL retry should happen for io-wq threads */
if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
goto done;
/* no retry on NONBLOCK nor RWF_NOWAIT */
if (req->flags & REQ_F_NOWAIT)
goto done;
ret = 0;
} else if (ret == -EIOCBQUEUED) {
goto out_free;
} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||
(req->flags & REQ_F_NOWAIT) || !need_read_all(req)) {
/* read all, failed, already did sync or don't want to retry */
goto done;
}
/*
* Don't depend on the iter state matching what was consumed, or being
* untouched in case of error. Restore it and we'll advance it
* manually if we need to.
*/
iov_iter_restore(&s->iter, &s->iter_state);
ret2 = io_setup_async_rw(req, iovec, s, true);
if (ret2)
return ret2;
iovec = NULL;
io = req->async_data;
s = &io->s;
/*
* Now use our persistent iterator and state, if we aren't already.
* We've restored and mapped the iter to match.
*/
do {
/*
* We end up here because of a partial read, either from
* above or inside this loop. Advance the iter by the bytes
* that were consumed.
*/
iov_iter_advance(&s->iter, ret);
if (!iov_iter_count(&s->iter))
break;
io->bytes_done += ret;
iov_iter_save_state(&s->iter, &s->iter_state);
/* if we can retry, do so with the callbacks armed */
if (!io_rw_should_retry(req)) {
kiocb->ki_flags &= ~IOCB_WAITQ;
return -EAGAIN;
}
/*
* Now retry read with the IOCB_WAITQ parts set in the iocb. If
* we get -EIOCBQUEUED, then we'll get a notification when the
* desired page gets unlocked. We can also get a partial read
* here, and if we do, then just retry at the new offset.
*/
ret = io_iter_do_read(rw, &s->iter);
if (ret == -EIOCBQUEUED)
return IOU_ISSUE_SKIP_COMPLETE;
/* we got some bytes, but not all. retry. */
kiocb->ki_flags &= ~IOCB_WAITQ;
iov_iter_restore(&s->iter, &s->iter_state);
} while (ret > 0);
done:
kiocb_done(req, ret, issue_flags);
out_free:
/* it's faster to check here then delegate to kfree */
if (iovec)
kfree(iovec);
return IOU_ISSUE_SKIP_COMPLETE;
}
static int io_write(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct io_rw_state __s, *s = &__s;
struct iovec *iovec;
struct kiocb *kiocb = &rw->kiocb;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
ssize_t ret, ret2;
loff_t *ppos;
if (!req_has_async_data(req)) {
ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
} else {
struct io_async_rw *io = req->async_data;
s = &io->s;
iov_iter_restore(&s->iter, &s->iter_state);
iovec = NULL;
}
ret = io_rw_init_file(req, FMODE_WRITE);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
req->cqe.res = iov_iter_count(&s->iter);
if (force_nonblock) {
/* If the file doesn't support async, just async punt */
if (unlikely(!io_file_supports_nowait(req)))
goto copy_iov;
/* file path doesn't support NOWAIT for non-direct_IO */
if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
(req->flags & REQ_F_ISREG))
goto copy_iov;
kiocb->ki_flags |= IOCB_NOWAIT;
} else {
/* Ensure we clear previously set non-block flag */
kiocb->ki_flags &= ~IOCB_NOWAIT;
}
ppos = io_kiocb_update_pos(req);
ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res);
if (unlikely(ret))
goto out_free;
/*
* Open-code file_start_write here to grab freeze protection,
* which will be released by another thread in
* io_complete_rw(). Fool lockdep by telling it the lock got
* released so that it doesn't complain about the held lock when
* we return to userspace.
*/
if (req->flags & REQ_F_ISREG) {
sb_start_write(file_inode(req->file)->i_sb);
__sb_writers_release(file_inode(req->file)->i_sb,
SB_FREEZE_WRITE);
}
kiocb->ki_flags |= IOCB_WRITE;
if (likely(req->file->f_op->write_iter))
ret2 = call_write_iter(req->file, kiocb, &s->iter);
else if (req->file->f_op->write)
ret2 = loop_rw_iter(WRITE, rw, &s->iter);
else
ret2 = -EINVAL;
if (req->flags & REQ_F_REISSUE) {
req->flags &= ~REQ_F_REISSUE;
ret2 = -EAGAIN;
}
/*
* Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
* retry them without IOCB_NOWAIT.
*/
if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
ret2 = -EAGAIN;
/* no retry on NONBLOCK nor RWF_NOWAIT */
if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
goto done;
if (!force_nonblock || ret2 != -EAGAIN) {
/* IOPOLL retry should happen for io-wq threads */
if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
goto copy_iov;
done:
kiocb_done(req, ret2, issue_flags);
ret = IOU_ISSUE_SKIP_COMPLETE;
} else {
copy_iov:
iov_iter_restore(&s->iter, &s->iter_state);
ret = io_setup_async_rw(req, iovec, s, false);
return ret ?: -EAGAIN;
}
out_free:
/* it's reportedly faster than delegating the null check to kfree() */
if (iovec)
kfree(iovec);
return ret;
}
static __maybe_unused int io_eopnotsupp_prep(struct io_kiocb *kiocb,
const struct io_uring_sqe *sqe)
{
return -EOPNOTSUPP;
}
static int io_req_prep_async(struct io_kiocb *req)
int io_req_prep_async(struct io_kiocb *req)
{
const struct io_op_def *def = &io_op_defs[req->opcode];
......
io_uring/io_uring.h
View file @ f3b44f92
......@@ -5,11 +5,125 @@
#include <linux/lockdep.h>
#include "io_uring_types.h"
#ifndef CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
#endif
enum {
IOU_OK = 0,
IOU_ISSUE_SKIP_COMPLETE = -EIOCBQUEUED,
};
bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data, s32 res,
u32 cflags, u64 extra1, u64 extra2);
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 inline 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 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 inline void req_set_fail(struct io_kiocb *req)
{
req->flags |= REQ_F_FAIL;
......@@ -64,6 +178,17 @@ static inline void io_commit_cqring(struct io_ring_ctx *ctx)
smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
}
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);
}
static inline bool io_sqring_full(struct io_ring_ctx *ctx)
{
struct io_rings *r = ctx->rings;
......@@ -100,6 +225,7 @@ void __io_req_complete_post(struct io_kiocb *req);
bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
u32 cflags);
void io_cqring_ev_posted(struct io_ring_ctx *ctx);
void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages);
......@@ -110,7 +236,10 @@ struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
bool io_is_uring_fops(struct file *file);
bool io_alloc_async_data(struct io_kiocb *req);
void io_req_task_work_add(struct io_kiocb *req);
void io_req_task_prio_work_add(struct io_kiocb *req);
void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags);
void io_req_task_queue(struct io_kiocb *req);
void io_queue_iowq(struct io_kiocb *req, bool *dont_use);
void io_req_task_complete(struct io_kiocb *req, bool *locked);
void io_req_task_queue_fail(struct io_kiocb *req, int ret);
void io_req_task_submit(struct io_kiocb *req, bool *locked);
......@@ -122,6 +251,8 @@ int io_uring_alloc_task_context(struct task_struct *task,
int io_poll_issue(struct io_kiocb *req, bool *locked);
int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node);
int io_req_prep_async(struct io_kiocb *req);
struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
void io_wq_submit_work(struct io_wq_work *work);
......
io_uring/rw.c 0 → 100644
View file @ f3b44f92
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/blk-mq.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/fsnotify.h>
#include <linux/poll.h>
#include <linux/nospec.h>
#include <linux/compat.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring_types.h"
#include "io_uring.h"
#include "opdef.h"
#include "kbuf.h"
#include "rsrc.h"
#include "rw.h"
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;
};
static inline bool io_file_supports_nowait(struct io_kiocb *req)
{
return req->flags & REQ_F_SUPPORT_NOWAIT;
}
int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
unsigned ioprio;
int ret;
rw->kiocb.ki_pos = READ_ONCE(sqe->off);
/* used for fixed read/write too - just read unconditionally */
req->buf_index = READ_ONCE(sqe->buf_index);
if (req->opcode == IORING_OP_READ_FIXED ||
req->opcode == IORING_OP_WRITE_FIXED) {
struct io_ring_ctx *ctx = req->ctx;
u16 index;
if (unlikely(req->buf_index >= ctx->nr_user_bufs))
return -EFAULT;
index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
req->imu = ctx->user_bufs[index];
io_req_set_rsrc_node(req, ctx, 0);
}
ioprio = READ_ONCE(sqe->ioprio);
if (ioprio) {
ret = ioprio_check_cap(ioprio);
if (ret)
return ret;
rw->kiocb.ki_ioprio = ioprio;
} else {
rw->kiocb.ki_ioprio = get_current_ioprio();
}
rw->addr = READ_ONCE(sqe->addr);
rw->len = READ_ONCE(sqe->len);
rw->flags = READ_ONCE(sqe->rw_flags);
return 0;
}
void io_readv_writev_cleanup(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
kfree(io->free_iovec);
}
static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
{
switch (ret) {
case -EIOCBQUEUED:
break;
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/*
* We can't just restart the syscall, since previously
* submitted sqes may already be in progress. Just fail this
* IO with EINTR.
*/
ret = -EINTR;
fallthrough;
default:
kiocb->ki_complete(kiocb, ret);
}
}
static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
if (rw->kiocb.ki_pos != -1)
return &rw->kiocb.ki_pos;
if (!(req->file->f_mode & FMODE_STREAM)) {
req->flags |= REQ_F_CUR_POS;
rw->kiocb.ki_pos = req->file->f_pos;
return &rw->kiocb.ki_pos;
}
rw->kiocb.ki_pos = 0;
return NULL;
}
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);
}
#ifdef CONFIG_BLOCK
static bool io_resubmit_prep(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
if (!req_has_async_data(req))
return !io_req_prep_async(req);
iov_iter_restore(&io->s.iter, &io->s.iter_state);
return true;
}
static bool io_rw_should_reissue(struct io_kiocb *req)
{
umode_t mode = file_inode(req->file)->i_mode;
struct io_ring_ctx *ctx = req->ctx;
if (!S_ISBLK(mode) && !S_ISREG(mode))
return false;
if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
!(ctx->flags & IORING_SETUP_IOPOLL)))
return false;
/*
* If ref is dying, we might be running poll reap from the exit work.
* Don't attempt to reissue from that path, just let it fail with
* -EAGAIN.
*/
if (percpu_ref_is_dying(&ctx->refs))
return false;
/*
* Play it safe and assume not safe to re-import and reissue if we're
* not in the original thread group (or in task context).
*/
if (!same_thread_group(req->task, current) || !in_task())
return false;
return true;
}
#else
static bool io_resubmit_prep(struct io_kiocb *req)
{
return false;
}
static bool io_rw_should_reissue(struct io_kiocb *req)
{
return false;
}
#endif
static void kiocb_end_write(struct io_kiocb *req)
{
/*
* Tell lockdep we inherited freeze protection from submission
* thread.
*/
if (req->flags & REQ_F_ISREG) {
struct super_block *sb = file_inode(req->file)->i_sb;
__sb_writers_acquired(sb, SB_FREEZE_WRITE);
sb_end_write(sb);
}
}
static bool __io_complete_rw_common(struct io_kiocb *req, long res)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
if (rw->kiocb.ki_flags & IOCB_WRITE) {
kiocb_end_write(req);
fsnotify_modify(req->file);
} else {
fsnotify_access(req->file);
}
if (unlikely(res != req->cqe.res)) {
if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
io_rw_should_reissue(req)) {
req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
return true;
}
req_set_fail(req);
req->cqe.res = res;
}
return false;
}
static void __io_complete_rw(struct io_kiocb *req, long res,
unsigned int issue_flags)
{
if (__io_complete_rw_common(req, res))
return;
io_req_set_res(req, req->cqe.res, io_put_kbuf(req, issue_flags));
__io_req_complete(req, issue_flags);
}
static void io_complete_rw(struct kiocb *kiocb, long res)
{
struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
struct io_kiocb *req = cmd_to_io_kiocb(rw);
if (__io_complete_rw_common(req, res))
return;
io_req_set_res(req, res, 0);
req->io_task_work.func = io_req_task_complete;
io_req_task_prio_work_add(req);
}
static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
{
struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
struct io_kiocb *req = cmd_to_io_kiocb(rw);
if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
if (unlikely(res != req->cqe.res)) {
if (res == -EAGAIN && io_rw_should_reissue(req)) {
req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
return;
}
req->cqe.res = res;
}
/* order with io_iopoll_complete() checking ->iopoll_completed */
smp_store_release(&req->iopoll_completed, 1);
}
static void kiocb_done(struct io_kiocb *req, ssize_t ret,
unsigned int issue_flags)
{
struct io_async_rw *io = req->async_data;
struct io_rw *rw = io_kiocb_to_cmd(req);
/* add previously done IO, if any */
if (req_has_async_data(req) && io->bytes_done > 0) {
if (ret < 0)
ret = io->bytes_done;
else
ret += io->bytes_done;
}
if (req->flags & REQ_F_CUR_POS)
req->file->f_pos = rw->kiocb.ki_pos;
if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw))
__io_complete_rw(req, ret, issue_flags);
else
io_rw_done(&rw->kiocb, ret);
if (req->flags & REQ_F_REISSUE) {
req->flags &= ~REQ_F_REISSUE;
if (io_resubmit_prep(req))
io_req_task_queue_reissue(req);
else
io_req_task_queue_fail(req, ret);
}
}
static int __io_import_fixed(struct io_kiocb *req, int ddir,
struct iov_iter *iter, struct io_mapped_ubuf *imu)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
size_t len = rw->len;
u64 buf_end, buf_addr = rw->addr;
size_t offset;
if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
return -EFAULT;
/* not inside the mapped region */
if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
return -EFAULT;
/*
* May not be a start of buffer, set size appropriately
* and advance us to the beginning.
*/
offset = buf_addr - imu->ubuf;
iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
if (offset) {
/*
* Don't use iov_iter_advance() here, as it's really slow for
* using the latter parts of a big fixed buffer - it iterates
* over each segment manually. We can cheat a bit here, because
* we know that:
*
* 1) it's a BVEC iter, we set it up
* 2) all bvecs are PAGE_SIZE in size, except potentially the
* first and last bvec
*
* So just find our index, and adjust the iterator afterwards.
* If the offset is within the first bvec (or the whole first
* bvec, just use iov_iter_advance(). This makes it easier
* since we can just skip the first segment, which may not
* be PAGE_SIZE aligned.
*/
const struct bio_vec *bvec = imu->bvec;
if (offset <= bvec->bv_len) {
iov_iter_advance(iter, offset);
} else {
unsigned long seg_skip;
/* skip first vec */
offset -= bvec->bv_len;
seg_skip = 1 + (offset >> PAGE_SHIFT);
iter->bvec = bvec + seg_skip;
iter->nr_segs -= seg_skip;
iter->count -= bvec->bv_len + offset;
iter->iov_offset = offset & ~PAGE_MASK;
}
}
return 0;
}
static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter,
unsigned int issue_flags)
{
if (WARN_ON_ONCE(!req->imu))
return -EFAULT;
return __io_import_fixed(req, rw, iter, req->imu);
}
#ifdef CONFIG_COMPAT
static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct compat_iovec __user *uiov;
compat_ssize_t clen;
void __user *buf;
size_t len;
uiov = u64_to_user_ptr(rw->addr);
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(clen, &uiov->iov_len))
return -EFAULT;
if (clen < 0)
return -EINVAL;
len = clen;
buf = io_buffer_select(req, &len, issue_flags);
if (!buf)
return -ENOBUFS;
rw->addr = (unsigned long) buf;
iov[0].iov_base = buf;
rw->len = iov[0].iov_len = (compat_size_t) len;
return 0;
}
#endif
static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct iovec __user *uiov = u64_to_user_ptr(rw->addr);
void __user *buf;
ssize_t len;
if (copy_from_user(iov, uiov, sizeof(*uiov)))
return -EFAULT;
len = iov[0].iov_len;
if (len < 0)
return -EINVAL;
buf = io_buffer_select(req, &len, issue_flags);
if (!buf)
return -ENOBUFS;
rw->addr = (unsigned long) buf;
iov[0].iov_base = buf;
rw->len = iov[0].iov_len = len;
return 0;
}
static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) {
iov[0].iov_base = u64_to_user_ptr(rw->addr);
iov[0].iov_len = rw->len;
return 0;
}
if (rw->len != 1)
return -EINVAL;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
return io_compat_import(req, iov, issue_flags);
#endif
return __io_iov_buffer_select(req, iov, issue_flags);
}
static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req,
struct io_rw_state *s,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct iov_iter *iter = &s->iter;
u8 opcode = req->opcode;
struct iovec *iovec;
void __user *buf;
size_t sqe_len;
ssize_t ret;
if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
ret = io_import_fixed(req, ddir, iter, issue_flags);
if (ret)
return ERR_PTR(ret);
return NULL;
}
buf = u64_to_user_ptr(rw->addr);
sqe_len = rw->len;
if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
if (io_do_buffer_select(req)) {
buf = io_buffer_select(req, &sqe_len, issue_flags);
if (!buf)
return ERR_PTR(-ENOBUFS);
rw->addr = (unsigned long) buf;
rw->len = sqe_len;
}
ret = import_single_range(ddir, buf, sqe_len, s->fast_iov, iter);
if (ret)
return ERR_PTR(ret);
return NULL;
}
iovec = s->fast_iov;
if (req->flags & REQ_F_BUFFER_SELECT) {
ret = io_iov_buffer_select(req, iovec, issue_flags);
if (ret)
return ERR_PTR(ret);
iov_iter_init(iter, ddir, iovec, 1, iovec->iov_len);
return NULL;
}
ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
req->ctx->compat);
if (unlikely(ret < 0))
return ERR_PTR(ret);
return iovec;
}
static inline int io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct io_rw_state *s,
unsigned int issue_flags)
{
*iovec = __io_import_iovec(rw, req, s, issue_flags);
if (unlikely(IS_ERR(*iovec)))
return PTR_ERR(*iovec);
iov_iter_save_state(&s->iter, &s->iter_state);
return 0;
}
static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
{
return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
}
/*
* For files that don't have ->read_iter() and ->write_iter(), handle them
* by looping over ->read() or ->write() manually.
*/
static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
{
struct kiocb *kiocb = &rw->kiocb;
struct file *file = kiocb->ki_filp;
ssize_t ret = 0;
loff_t *ppos;
/*
* Don't support polled IO through this interface, and we can't
* support non-blocking either. For the latter, this just causes
* the kiocb to be handled from an async context.
*/
if (kiocb->ki_flags & IOCB_HIPRI)
return -EOPNOTSUPP;
if ((kiocb->ki_flags & IOCB_NOWAIT) &&
!(kiocb->ki_filp->f_flags & O_NONBLOCK))
return -EAGAIN;
ppos = io_kiocb_ppos(kiocb);
while (iov_iter_count(iter)) {
struct iovec iovec;
ssize_t nr;
if (!iov_iter_is_bvec(iter)) {
iovec = iov_iter_iovec(iter);
} else {
iovec.iov_base = u64_to_user_ptr(rw->addr);
iovec.iov_len = rw->len;
}
if (ddir == READ) {
nr = file->f_op->read(file, iovec.iov_base,
iovec.iov_len, ppos);
} else {
nr = file->f_op->write(file, iovec.iov_base,
iovec.iov_len, ppos);
}
if (nr < 0) {
if (!ret)
ret = nr;
break;
}
ret += nr;
if (!iov_iter_is_bvec(iter)) {
iov_iter_advance(iter, nr);
} else {
rw->addr += nr;
rw->len -= nr;
if (!rw->len)
break;
}
if (nr != iovec.iov_len)
break;
}
return ret;
}
static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
const struct iovec *fast_iov, struct iov_iter *iter)
{
struct io_async_rw *io = req->async_data;
memcpy(&io->s.iter, iter, sizeof(*iter));
io->free_iovec = iovec;
io->bytes_done = 0;
/* can only be fixed buffers, no need to do anything */
if (iov_iter_is_bvec(iter))
return;
if (!iovec) {
unsigned iov_off = 0;
io->s.iter.iov = io->s.fast_iov;
if (iter->iov != fast_iov) {
iov_off = iter->iov - fast_iov;
io->s.iter.iov += iov_off;
}
if (io->s.fast_iov != fast_iov)
memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off,
sizeof(struct iovec) * iter->nr_segs);
} else {
req->flags |= REQ_F_NEED_CLEANUP;
}
}
static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
struct io_rw_state *s, bool force)
{
if (!force && !io_op_defs[req->opcode].prep_async)
return 0;
if (!req_has_async_data(req)) {
struct io_async_rw *iorw;
if (io_alloc_async_data(req)) {
kfree(iovec);
return -ENOMEM;
}
io_req_map_rw(req, iovec, s->fast_iov, &s->iter);
iorw = req->async_data;
/* we've copied and mapped the iter, ensure state is saved */
iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state);
}
return 0;
}
static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
{
struct io_async_rw *iorw = req->async_data;
struct iovec *iov;
int ret;
/* submission path, ->uring_lock should already be taken */
ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
if (unlikely(ret < 0))
return ret;
iorw->bytes_done = 0;
iorw->free_iovec = iov;
if (iov)
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
int io_readv_prep_async(struct io_kiocb *req)
{
return io_rw_prep_async(req, READ);
}
int io_writev_prep_async(struct io_kiocb *req)
{
return io_rw_prep_async(req, WRITE);
}
/*
* This is our waitqueue callback handler, registered through __folio_lock_async()
* when we initially tried to do the IO with the iocb armed our waitqueue.
* This gets called when the page is unlocked, and we generally expect that to
* happen when the page IO is completed and the page is now uptodate. This will
* queue a task_work based retry of the operation, attempting to copy the data
* again. If the latter fails because the page was NOT uptodate, then we will
* do a thread based blocking retry of the operation. That's the unexpected
* slow path.
*/
static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
int sync, void *arg)
{
struct wait_page_queue *wpq;
struct io_kiocb *req = wait->private;
struct io_rw *rw = io_kiocb_to_cmd(req);
struct wait_page_key *key = arg;
wpq = container_of(wait, struct wait_page_queue, wait);
if (!wake_page_match(wpq, key))
return 0;
rw->kiocb.ki_flags &= ~IOCB_WAITQ;
list_del_init(&wait->entry);
io_req_task_queue(req);
return 1;
}
/*
* This controls whether a given IO request should be armed for async page
* based retry. If we return false here, the request is handed to the async
* worker threads for retry. If we're doing buffered reads on a regular file,
* we prepare a private wait_page_queue entry and retry the operation. This
* will either succeed because the page is now uptodate and unlocked, or it
* will register a callback when the page is unlocked at IO completion. Through
* that callback, io_uring uses task_work to setup a retry of the operation.
* That retry will attempt the buffered read again. The retry will generally
* succeed, or in rare cases where it fails, we then fall back to using the
* async worker threads for a blocking retry.
*/
static bool io_rw_should_retry(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
struct wait_page_queue *wait = &io->wpq;
struct io_rw *rw = io_kiocb_to_cmd(req);
struct kiocb *kiocb = &rw->kiocb;
/* never retry for NOWAIT, we just complete with -EAGAIN */
if (req->flags & REQ_F_NOWAIT)
return false;
/* Only for buffered IO */
if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
return false;
/*
* just use poll if we can, and don't attempt if the fs doesn't
* support callback based unlocks
*/
if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
return false;
wait->wait.func = io_async_buf_func;
wait->wait.private = req;
wait->wait.flags = 0;
INIT_LIST_HEAD(&wait->wait.entry);
kiocb->ki_flags |= IOCB_WAITQ;
kiocb->ki_flags &= ~IOCB_NOWAIT;
kiocb->ki_waitq = wait;
return true;
}
static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter)
{
struct file *file = rw->kiocb.ki_filp;
if (likely(file->f_op->read_iter))
return call_read_iter(file, &rw->kiocb, iter);
else if (file->f_op->read)
return loop_rw_iter(READ, rw, iter);
else
return -EINVAL;
}
static bool need_read_all(struct io_kiocb *req)
{
return req->flags & REQ_F_ISREG ||
S_ISBLK(file_inode(req->file)->i_mode);
}
static inline bool io_req_ffs_set(struct io_kiocb *req)
{
return req->flags & REQ_F_FIXED_FILE;
}
static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct kiocb *kiocb = &rw->kiocb;
struct io_ring_ctx *ctx = req->ctx;
struct file *file = req->file;
int ret;
if (unlikely(!file || !(file->f_mode & mode)))
return -EBADF;
if (!io_req_ffs_set(req))
req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT;
kiocb->ki_flags = iocb_flags(file);
ret = kiocb_set_rw_flags(kiocb, rw->flags);
if (unlikely(ret))
return ret;
/*
* If the file is marked O_NONBLOCK, still allow retry for it if it
* supports async. Otherwise it's impossible to use O_NONBLOCK files
* reliably. If not, or it IOCB_NOWAIT is set, don't retry.
*/
if ((kiocb->ki_flags & IOCB_NOWAIT) ||
((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
req->flags |= REQ_F_NOWAIT;
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
return -EOPNOTSUPP;
kiocb->private = NULL;
kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE;
kiocb->ki_complete = io_complete_rw_iopoll;
req->iopoll_completed = 0;
} else {
if (kiocb->ki_flags & IOCB_HIPRI)
return -EINVAL;
kiocb->ki_complete = io_complete_rw;
}
return 0;
}
int io_read(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct io_rw_state __s, *s = &__s;
struct iovec *iovec;
struct kiocb *kiocb = &rw->kiocb;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
struct io_async_rw *io;
ssize_t ret, ret2;
loff_t *ppos;
if (!req_has_async_data(req)) {
ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
} else {
io = req->async_data;
s = &io->s;
/*
* Safe and required to re-import if we're using provided
* buffers, as we dropped the selected one before retry.
*/
if (io_do_buffer_select(req)) {
ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
}
/*
* We come here from an earlier attempt, restore our state to
* match in case it doesn't. It's cheap enough that we don't
* need to make this conditional.
*/
iov_iter_restore(&s->iter, &s->iter_state);
iovec = NULL;
}
ret = io_rw_init_file(req, FMODE_READ);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
req->cqe.res = iov_iter_count(&s->iter);
if (force_nonblock) {
/* If the file doesn't support async, just async punt */
if (unlikely(!io_file_supports_nowait(req))) {
ret = io_setup_async_rw(req, iovec, s, true);
return ret ?: -EAGAIN;
}
kiocb->ki_flags |= IOCB_NOWAIT;
} else {
/* Ensure we clear previously set non-block flag */
kiocb->ki_flags &= ~IOCB_NOWAIT;
}
ppos = io_kiocb_update_pos(req);
ret = rw_verify_area(READ, req->file, ppos, req->cqe.res);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
ret = io_iter_do_read(rw, &s->iter);
if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
req->flags &= ~REQ_F_REISSUE;
/* if we can poll, just do that */
if (req->opcode == IORING_OP_READ && file_can_poll(req->file))
return -EAGAIN;
/* IOPOLL retry should happen for io-wq threads */
if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
goto done;
/* no retry on NONBLOCK nor RWF_NOWAIT */
if (req->flags & REQ_F_NOWAIT)
goto done;
ret = 0;
} else if (ret == -EIOCBQUEUED) {
goto out_free;
} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||
(req->flags & REQ_F_NOWAIT) || !need_read_all(req)) {
/* read all, failed, already did sync or don't want to retry */
goto done;
}
/*
* Don't depend on the iter state matching what was consumed, or being
* untouched in case of error. Restore it and we'll advance it
* manually if we need to.
*/
iov_iter_restore(&s->iter, &s->iter_state);
ret2 = io_setup_async_rw(req, iovec, s, true);
if (ret2)
return ret2;
iovec = NULL;
io = req->async_data;
s = &io->s;
/*
* Now use our persistent iterator and state, if we aren't already.
* We've restored and mapped the iter to match.
*/
do {
/*
* We end up here because of a partial read, either from
* above or inside this loop. Advance the iter by the bytes
* that were consumed.
*/
iov_iter_advance(&s->iter, ret);
if (!iov_iter_count(&s->iter))
break;
io->bytes_done += ret;
iov_iter_save_state(&s->iter, &s->iter_state);
/* if we can retry, do so with the callbacks armed */
if (!io_rw_should_retry(req)) {
kiocb->ki_flags &= ~IOCB_WAITQ;
return -EAGAIN;
}
/*
* Now retry read with the IOCB_WAITQ parts set in the iocb. If
* we get -EIOCBQUEUED, then we'll get a notification when the
* desired page gets unlocked. We can also get a partial read
* here, and if we do, then just retry at the new offset.
*/
ret = io_iter_do_read(rw, &s->iter);
if (ret == -EIOCBQUEUED)
return IOU_ISSUE_SKIP_COMPLETE;
/* we got some bytes, but not all. retry. */
kiocb->ki_flags &= ~IOCB_WAITQ;
iov_iter_restore(&s->iter, &s->iter_state);
} while (ret > 0);
done:
kiocb_done(req, ret, issue_flags);
out_free:
/* it's faster to check here then delegate to kfree */
if (iovec)
kfree(iovec);
return IOU_ISSUE_SKIP_COMPLETE;
}
int io_write(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req);
struct io_rw_state __s, *s = &__s;
struct iovec *iovec;
struct kiocb *kiocb = &rw->kiocb;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
ssize_t ret, ret2;
loff_t *ppos;
if (!req_has_async_data(req)) {
ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
} else {
struct io_async_rw *io = req->async_data;
s = &io->s;
iov_iter_restore(&s->iter, &s->iter_state);
iovec = NULL;
}
ret = io_rw_init_file(req, FMODE_WRITE);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
req->cqe.res = iov_iter_count(&s->iter);
if (force_nonblock) {
/* If the file doesn't support async, just async punt */
if (unlikely(!io_file_supports_nowait(req)))
goto copy_iov;
/* file path doesn't support NOWAIT for non-direct_IO */
if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
(req->flags & REQ_F_ISREG))
goto copy_iov;
kiocb->ki_flags |= IOCB_NOWAIT;
} else {
/* Ensure we clear previously set non-block flag */
kiocb->ki_flags &= ~IOCB_NOWAIT;
}
ppos = io_kiocb_update_pos(req);
ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res);
if (unlikely(ret))
goto out_free;
/*
* Open-code file_start_write here to grab freeze protection,
* which will be released by another thread in
* io_complete_rw(). Fool lockdep by telling it the lock got
* released so that it doesn't complain about the held lock when
* we return to userspace.
*/
if (req->flags & REQ_F_ISREG) {
sb_start_write(file_inode(req->file)->i_sb);
__sb_writers_release(file_inode(req->file)->i_sb,
SB_FREEZE_WRITE);
}
kiocb->ki_flags |= IOCB_WRITE;
if (likely(req->file->f_op->write_iter))
ret2 = call_write_iter(req->file, kiocb, &s->iter);
else if (req->file->f_op->write)
ret2 = loop_rw_iter(WRITE, rw, &s->iter);
else
ret2 = -EINVAL;
if (req->flags & REQ_F_REISSUE) {
req->flags &= ~REQ_F_REISSUE;
ret2 = -EAGAIN;
}
/*
* Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
* retry them without IOCB_NOWAIT.
*/
if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
ret2 = -EAGAIN;
/* no retry on NONBLOCK nor RWF_NOWAIT */
if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
goto done;
if (!force_nonblock || ret2 != -EAGAIN) {
/* IOPOLL retry should happen for io-wq threads */
if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
goto copy_iov;
done:
kiocb_done(req, ret2, issue_flags);
ret = IOU_ISSUE_SKIP_COMPLETE;
} else {
copy_iov:
iov_iter_restore(&s->iter, &s->iter_state);
ret = io_setup_async_rw(req, iovec, s, false);
return ret ?: -EAGAIN;
}
out_free:
/* it's reportedly faster than delegating the null check to kfree() */
if (iovec)
kfree(iovec);
return ret;
}
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);
}
int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
{
struct io_wq_work_node *pos, *start, *prev;
unsigned int poll_flags = BLK_POLL_NOSLEEP;
DEFINE_IO_COMP_BATCH(iob);
int nr_events = 0;
/*
* Only spin for completions if we don't have multiple devices hanging
* off our complete list.
*/
if (ctx->poll_multi_queue || force_nonspin)
poll_flags |= BLK_POLL_ONESHOT;
wq_list_for_each(pos, start, &ctx->iopoll_list) {
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
struct io_rw *rw = io_kiocb_to_cmd(req);
int ret;
/*
* Move completed and retryable entries to our local lists.
* If we find a request that requires polling, break out
* and complete those lists first, if we have entries there.
*/
if (READ_ONCE(req->iopoll_completed))
break;
ret = rw->kiocb.ki_filp->f_op->iopoll(&rw->kiocb, &iob, poll_flags);
if (unlikely(ret < 0))
return ret;
else if (ret)
poll_flags |= BLK_POLL_ONESHOT;
/* iopoll may have completed current req */
if (!rq_list_empty(iob.req_list) ||
READ_ONCE(req->iopoll_completed))
break;
}
if (!rq_list_empty(iob.req_list))
iob.complete(&iob);
else if (!pos)
return 0;
prev = start;
wq_list_for_each_resume(pos, prev) {
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
/* order with io_complete_rw_iopoll(), e.g. ->result updates */
if (!smp_load_acquire(&req->iopoll_completed))
break;
nr_events++;
if (unlikely(req->flags & REQ_F_CQE_SKIP))
continue;
req->cqe.flags = io_put_kbuf(req, 0);
__io_fill_cqe_req(req->ctx, req);
}
if (unlikely(!nr_events))
return 0;
io_commit_cqring(ctx);
io_cqring_ev_posted_iopoll(ctx);
pos = start ? start->next : ctx->iopoll_list.first;
wq_list_cut(&ctx->iopoll_list, prev, start);
io_free_batch_list(ctx, pos);
return nr_events;
}
io_uring/rw.h 0 → 100644
View file @ f3b44f92
// SPDX-License-Identifier: GPL-2.0
#include <linux/pagemap.h>
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;
};
int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_read(struct io_kiocb *req, unsigned int issue_flags);
int io_readv_prep_async(struct io_kiocb *req);
int io_write(struct io_kiocb *req, unsigned int issue_flags);
int io_writev_prep_async(struct io_kiocb *req);
void io_readv_writev_cleanup(struct io_kiocb *req);
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