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From: Kevin Wolf <kwolf@redhat.com>
To: lishan <lishan24@huawei.com>
Cc: hreitz@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org,
	eric.fangyi@huawei.com
Subject: Re: [PATCH] block/file-posix: Limit max_iov to IOV_MAX
Date: Mon, 20 Sep 2021 10:14:26 +0200	[thread overview]
Message-ID: <YUhC4pvNdlmnMzsh@redhat.com> (raw)
In-Reply-To: <20210918073300.30224-1-lishan24@huawei.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
> 
> 



  reply	other threads:[~2021-09-20  8:23 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-18  7:33 lishan
2021-09-20  8:14 ` Kevin Wolf [this message]
  -- strict thread matches above, loose matches on Subject: below --
2021-09-18  4:06 lishan
2021-09-20  4:47 ` Markus Armbruster
2021-09-20  9:03 ` Daniel P. Berrangé

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