redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

io_uring: fix hanging iopoll in case of -EAGAIN 

io_do_iopoll() won't do anything with a request unless
req->iopoll_completed is set. So io_complete_rw_iopoll() has to set
it, otherwise io_do_iopoll() will poll a file again and again even
though the request of interest was completed long time ago.

Also, remove -EAGAIN check from io_issue_sqe() as it races with
the changed lines. The request will take the long way and be
resubmitted from io_iopoll*().

io_kiocb's result and iopoll_completed")

Fixes: bbde017a32 ("io_uring: add memory barrier to synchronize
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
alistair/sunxi64-5.8
Pavel Begunkov 2020-06-25 12:37:10 +03:00 committed by Jens Axboe
parent b772f07add
commit cd664b0e35
1 changed files with 2 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
fs/io_uring.c
View File

@ -1994,10 +1994,8 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
WRITE_ONCE(req->result, res);
/* order with io_poll_complete() checking ->result */
if (res != -EAGAIN) {
smp_wmb();
WRITE_ONCE(req->iopoll_completed, 1);
}
smp_wmb();
WRITE_ONCE(req->iopoll_completed, 1);
}
/*
@ -5353,9 +5351,6 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file) {
const bool in_async = io_wq_current_is_worker();
if (req->result == -EAGAIN)
return -EAGAIN;
/* workqueue context doesn't hold uring_lock, grab it now */
if (in_async)
mutex_lock(&ctx->uring_lock);