Commit f873db9a authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'io_uring-5.9-2020-08-21' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:

 - Make sure the head link cancelation includes async work

 - Get rid of kiocb_wait_page_queue_init(), makes no sense to have it as
   a separate function since you moved it into io_uring itself

 - io_import_iovec cleanups (Pavel, me)

 - Use system_unbound_wq for ring exit work, to avoid spawning tons of
   these if we have tons of rings exiting at the same time

 - Fix req->flags overflow flag manipulation (Pavel)

* tag 'io_uring-5.9-2020-08-21' of git://git.kernel.dk/linux-block:
  io_uring: kill extra iovec=NULL in import_iovec()
  io_uring: comment on kfree(iovec) checks
  io_uring: fix racy req->flags modification
  io_uring: use system_unbound_wq for ring exit work
  io_uring: cleanup io_import_iovec() of pre-mapped request
  io_uring: get rid of kiocb_wait_page_queue_init()
  io_uring: find and cancel head link async work on files exit
parents 349111f0 867a23ea
......@@ -540,7 +540,6 @@ enum {
REQ_F_ISREG_BIT,
REQ_F_COMP_LOCKED_BIT,
REQ_F_NEED_CLEANUP_BIT,
REQ_F_OVERFLOW_BIT,
REQ_F_POLLED_BIT,
REQ_F_BUFFER_SELECTED_BIT,
REQ_F_NO_FILE_TABLE_BIT,
......@@ -583,8 +582,6 @@ enum {
REQ_F_COMP_LOCKED = BIT(REQ_F_COMP_LOCKED_BIT),
/* needs cleanup */
REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT),
/* in overflow list */
REQ_F_OVERFLOW = BIT(REQ_F_OVERFLOW_BIT),
/* already went through poll handler */
REQ_F_POLLED = BIT(REQ_F_POLLED_BIT),
/* buffer already selected */
......@@ -946,7 +943,8 @@ static void io_get_req_task(struct io_kiocb *req)
static inline void io_clean_op(struct io_kiocb *req)
{
if (req->flags & (REQ_F_NEED_CLEANUP | REQ_F_BUFFER_SELECTED))
if (req->flags & (REQ_F_NEED_CLEANUP | REQ_F_BUFFER_SELECTED |
REQ_F_INFLIGHT))
__io_clean_op(req);
}
......@@ -1366,7 +1364,6 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
req = list_first_entry(&ctx->cq_overflow_list, struct io_kiocb,
compl.list);
list_move(&req->compl.list, &list);
req->flags &= ~REQ_F_OVERFLOW;
if (cqe) {
WRITE_ONCE(cqe->user_data, req->user_data);
WRITE_ONCE(cqe->res, req->result);
......@@ -1419,7 +1416,6 @@ static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags)
ctx->rings->sq_flags |= IORING_SQ_CQ_OVERFLOW;
}
io_clean_op(req);
req->flags |= REQ_F_OVERFLOW;
req->result = res;
req->compl.cflags = cflags;
refcount_inc(&req->refs);
......@@ -1563,17 +1559,6 @@ static bool io_dismantle_req(struct io_kiocb *req)
if (req->file)
io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
if (req->flags & REQ_F_INFLIGHT) {
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->inflight_lock, flags);
list_del(&req->inflight_entry);
if (waitqueue_active(&ctx->inflight_wait))
wake_up(&ctx->inflight_wait);
spin_unlock_irqrestore(&ctx->inflight_lock, flags);
}
return io_req_clean_work(req);
}
......@@ -2819,22 +2804,15 @@ static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
return __io_iov_buffer_select(req, iov, needs_lock);
}
static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter,
bool needs_lock)
static ssize_t __io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter,
bool needs_lock)
{
void __user *buf = u64_to_user_ptr(req->rw.addr);
size_t sqe_len = req->rw.len;
ssize_t ret;
u8 opcode;
if (req->io) {
struct io_async_rw *iorw = &req->io->rw;
*iovec = NULL;
return iov_iter_count(&iorw->iter);
}
opcode = req->opcode;
if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
*iovec = NULL;
......@@ -2848,10 +2826,8 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
if (req->flags & REQ_F_BUFFER_SELECT) {
buf = io_rw_buffer_select(req, &sqe_len, needs_lock);
if (IS_ERR(buf)) {
*iovec = NULL;
if (IS_ERR(buf))
return PTR_ERR(buf);
}
req->rw.len = sqe_len;
}
......@@ -2879,6 +2855,16 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
}
static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter,
bool needs_lock)
{
if (!req->io)
return __io_import_iovec(rw, req, iovec, iter, needs_lock);
*iovec = NULL;
return iov_iter_count(&req->io->rw.iter);
}
/*
* For files that don't have ->read_iter() and ->write_iter(), handle them
* by looping over ->read() or ->write() manually.
......@@ -3001,11 +2987,8 @@ static inline int io_rw_prep_async(struct io_kiocb *req, int rw,
ssize_t ret;
iorw->iter.iov = iorw->fast_iov;
/* reset ->io around the iovec import, we don't want to use it */
req->io = NULL;
ret = io_import_iovec(rw, req, (struct iovec **) &iorw->iter.iov,
ret = __io_import_iovec(rw, req, (struct iovec **) &iorw->iter.iov,
&iorw->iter, !force_nonblock);
req->io = container_of(iorw, struct io_async_ctx, rw);
if (unlikely(ret < 0))
return ret;
......@@ -3074,27 +3057,6 @@ static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
return 1;
}
static inline int kiocb_wait_page_queue_init(struct kiocb *kiocb,
struct wait_page_queue *wait,
wait_queue_func_t func,
void *data)
{
/* Can't support async wakeup with polled IO */
if (kiocb->ki_flags & IOCB_HIPRI)
return -EINVAL;
if (kiocb->ki_filp->f_mode & FMODE_BUF_RASYNC) {
wait->wait.func = func;
wait->wait.private = data;
wait->wait.flags = 0;
INIT_LIST_HEAD(&wait->wait.entry);
kiocb->ki_flags |= IOCB_WAITQ;
kiocb->ki_waitq = wait;
return 0;
}
return -EOPNOTSUPP;
}
/*
* 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
......@@ -3109,16 +3071,17 @@ static inline int kiocb_wait_page_queue_init(struct kiocb *kiocb,
*/
static bool io_rw_should_retry(struct io_kiocb *req)
{
struct wait_page_queue *wait = &req->io->rw.wpq;
struct kiocb *kiocb = &req->rw.kiocb;
int ret;
/* 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)
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
......@@ -3126,14 +3089,15 @@ static bool io_rw_should_retry(struct io_kiocb *req)
if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
return false;
ret = kiocb_wait_page_queue_init(kiocb, &req->io->rw.wpq,
io_async_buf_func, req);
if (!ret) {
io_get_req_task(req);
return true;
}
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_waitq = wait;
return false;
io_get_req_task(req);
return true;
}
static int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter)
......@@ -3238,6 +3202,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
kiocb_done(kiocb, ret, cs);
ret = 0;
out_free:
/* it's reportedly faster than delegating the null check to kfree() */
if (iovec)
kfree(iovec);
return ret;
......@@ -3334,6 +3299,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
return -EAGAIN;
}
out_free:
/* it's reportedly faster than delegating the null check to kfree() */
if (iovec)
kfree(iovec);
return ret;
......@@ -5653,6 +5619,18 @@ static void __io_clean_op(struct io_kiocb *req)
}
req->flags &= ~REQ_F_NEED_CLEANUP;
}
if (req->flags & REQ_F_INFLIGHT) {
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->inflight_lock, flags);
list_del(&req->inflight_entry);
if (waitqueue_active(&ctx->inflight_wait))
wake_up(&ctx->inflight_wait);
spin_unlock_irqrestore(&ctx->inflight_lock, flags);
req->flags &= ~REQ_F_INFLIGHT;
}
}
static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
......@@ -7979,7 +7957,13 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
ACCT_LOCKED);
INIT_WORK(&ctx->exit_work, io_ring_exit_work);
queue_work(system_wq, &ctx->exit_work);
/*
* Use system_unbound_wq to avoid spawning tons of event kworkers
* if we're exiting a ton of rings at the same time. It just adds
* noise and overhead, there's no discernable change in runtime
* over using system_wq.
*/
queue_work(system_unbound_wq, &ctx->exit_work);
}
static int io_uring_release(struct inode *inode, struct file *file)
......@@ -8063,6 +8047,33 @@ static bool io_timeout_remove_link(struct io_ring_ctx *ctx,
return found;
}
static bool io_cancel_link_cb(struct io_wq_work *work, void *data)
{
return io_match_link(container_of(work, struct io_kiocb, work), data);
}
static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
{
enum io_wq_cancel cret;
/* cancel this particular work, if it's running */
cret = io_wq_cancel_work(ctx->io_wq, &req->work);
if (cret != IO_WQ_CANCEL_NOTFOUND)
return;
/* find links that hold this pending, cancel those */
cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_link_cb, req, true);
if (cret != IO_WQ_CANCEL_NOTFOUND)
return;
/* if we have a poll link holding this pending, cancel that */
if (io_poll_remove_link(ctx, req))
return;
/* final option, timeout link is holding this req pending */
io_timeout_remove_link(ctx, req);
}
static void io_uring_cancel_files(struct io_ring_ctx *ctx,
struct files_struct *files)
{
......@@ -8094,35 +8105,9 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
/* We need to keep going until we don't find a matching req */
if (!cancel_req)
break;
if (cancel_req->flags & REQ_F_OVERFLOW) {
spin_lock_irq(&ctx->completion_lock);
list_del(&cancel_req->compl.list);
cancel_req->flags &= ~REQ_F_OVERFLOW;
io_cqring_mark_overflow(ctx);
WRITE_ONCE(ctx->rings->cq_overflow,
atomic_inc_return(&ctx->cached_cq_overflow));
io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);
/*
* Put inflight ref and overflow ref. If that's
* all we had, then we're done with this request.
*/
if (refcount_sub_and_test(2, &cancel_req->refs)) {
io_free_req(cancel_req);
finish_wait(&ctx->inflight_wait, &wait);
continue;
}
} else {
io_wq_cancel_work(ctx->io_wq, &cancel_req->work);
/* could be a link, check and remove if it is */
if (!io_poll_remove_link(ctx, cancel_req))
io_timeout_remove_link(ctx, cancel_req);
io_put_req(cancel_req);
}
/* cancel this request, or head link requests */
io_attempt_cancel(ctx, cancel_req);
io_put_req(cancel_req);
schedule();
finish_wait(&ctx->inflight_wait, &wait);
}
......
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