Re: [PATCH] block/file-posix: Limit max_iov to IOV_MAX

[Kevin Wolf <kwolf@redhat.com>]

Am 18.09.2021 um 09:33 hat lishan geschrieben:
> AIO read/write. The size of iocb->aio_nbytes in the kernel cannot exceed UIO_MAXIOV = 1024.
> max_segments read from the block device layer may be greater than UIO_MAXIOV,
> this causes the ioq_submit interface to return a -22(-EINVAL) error result.

You need a Signed-off-by line so that a patch can be accepted.

But Paolo intended to send a better solution anyway (splitting max_iov
into two separate limits). Not sure what the status is there.

Kevin

>  block/file-posix.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/block/file-posix.c b/block/file-posix.c
> index d81e15efa4..27ab8d8784 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1273,7 +1273,8 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
>  
>          ret = hdev_get_max_segments(s->fd, &st);
>          if (ret > 0) {
> -            bs->bl.max_iov = ret;
> +            /* The maximum segment size allowed by the kernel is UIO_MAXIOV = 1024. */
> +            bs->bl.max_iov = MIN(ret, bs->bl.max_iov);
>          }
>      }
>  }
> -- 
> 2.19.1.windows.1
> 
>