Re: [PATCH] block/export: improve vu_blk_sect_range_ok()

[Stefan Hajnoczi]

On Wed, Mar 31, 2021 at 03:27:27PM +0100, Stefan Hajnoczi wrote:
> The checks in vu_blk_sect_range_ok() assume VIRTIO_BLK_SECTOR_SIZE is
> equal to BDRV_SECTOR_SIZE. This is true, but let's add a
> QEMU_BUILD_BUG_ON() to make it explicit.
> 
> We might as well check that the request buffer size is a multiple of
> VIRTIO_BLK_SECTOR_SIZE while we're at it.
> 
> Suggested-by: Max Reitz <mreitz@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  block/export/vhost-user-blk-server.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)

Ping for QEMU 6.1.

Stefan

> 
> diff --git a/block/export/vhost-user-blk-server.c 
> b/block/export/vhost-user-blk-server.c
> index fa06996d37..1862563336 100644
> --- a/block/export/vhost-user-blk-server.c
> +++ b/block/export/vhost-user-blk-server.c
> @@ -70,9 +70,16 @@ static void vu_blk_req_complete(VuBlkReq *req)
>  static bool vu_blk_sect_range_ok(VuBlkExport *vexp, uint64_t sector,
>                                   size_t size)
>  {
> -    uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
> +    uint64_t nb_sectors;
>      uint64_t total_sectors;
>  
> +    if (size % VIRTIO_BLK_SECTOR_SIZE) {
> +        return false;
> +    }
> +
> +    nb_sectors = size >> VIRTIO_BLK_SECTOR_BITS;
> +
> +    QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != VIRTIO_BLK_SECTOR_SIZE);
>      if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>          return false;
>      }
> -- 
> 2.30.2
>

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