Re: 5.8 io_uring stable

On Fri, Sep 04, 2020 at 03:06:28PM -0600, Jens Axboe wrote:

Hi,

Linus just pulled 3 fixes from me - 1+2 should apply directly, here's the 3rd one which will need some love for 5.8-stable. I'm including it below to preempt the failed to apply message :-)

commit fb8d4046d50f77a26570101e5b8a7a026320a610 Author: Jens Axboe axboe@kernel.dk Date: Wed Sep 2 10:19:04 2020 -0600

io_uring: no read/write-retry on -EAGAIN error and O_NONBLOCK marked file

Actually two things that need fixing up here: - The io_rw_reissue() -EAGAIN retry is explicit to block devices and regular files, so don't ever attempt to do that on other types of files. - If we hit -EAGAIN on a nonblock marked file, don't arm poll handler for it. It should just complete with -EAGAIN. Cc: stable@vger.kernel.org Reported-by: Norman Maurer norman.maurer@googlemail.com Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/fs/io_uring.c b/fs/io_uring.c index 82e15020d9a8..96be21ace79a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2726,6 +2726,12 @@ static int io_read(struct io_kiocb *req, bool force_nonblock) ret = ret2; goto done; }

• 	/* no retry on NONBLOCK marked file */
  

• 	if (req->file->f_flags & O_NONBLOCK) {
  

• 		ret = ret2;
  

• 		goto done;
  

• 	}
  

• /* some cases will consume bytes even on error returns */
  iov_iter_revert(iter, iov_count - iov_iter_count(iter));
  ret2 = 0;
  

@@ -2869,9 +2875,15 @@ static int io_write(struct io_kiocb *req, bool force_nonblock) */ if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) ret2 = -EAGAIN;

• /* no retry on NONBLOCK marked file */
  

• if (ret2 == -EAGAIN && (req->file->f_flags & O_NONBLOCK)) {
  

• 	ret = 0;
  

• 	goto done;
  

• }
  

  if (!force_nonblock || ret2 != -EAGAIN) { if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN) goto copy_iov;

+done: kiocb_done(kiocb, ret2); } else { copy_iov:

-- Jens Axboe

Thanks for the backport, but this didn't apply at all to the 5.8.y tree. What one did you make it against?

thanks,

greg k-h