Commit ef046888 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: don't block level reissue off completion path 



Some setups, like SCSI, can throw spurious -EAGAIN off the softirq
completion path. Normally we expect this to happen inline as part
of submission, but apparently SCSI has a weird corner case where it
can happen as part of normal completions.

This should be solved by having the -EAGAIN bubble back up the stack
as part of submission, but previous attempts at this failed and we're
not just quite there yet. Instead we currently use REQ_F_REISSUE to
handle this case.

For now, catch it in io_rw_should_reissue() and prevent a reissue
from a bogus path.

Cc: stable@vger.kernel.org
Reported-by: default avatarFabian Ebner <f.ebner@proxmox.com>
Tested-by: default avatarFabian Ebner <f.ebner@proxmox.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 773af691

fs/io_uring.c

+6 −0
Original line number Diff line number Diff line
@@ -2447,6 +2447,12 @@ static bool io_rw_should_reissue(struct io_kiocb *req) 
	 */

	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