Re: [bug report] vdpa_sim_blk: implement ramdisk behaviour

[Dan Carpenter <dan.carpenter@oracle.com>]

On Wed, Sep 29, 2021 at 02:37:42PM +0300, Dan Carpenter wrote:
>     89         /* The last byte is the status and we checked if the last iov has
>     90          * enough room for it.
>     91          */
>     92         to_push = vringh_kiov_length(&vq->in_iov) - 1;
> 
> Are you positive that vringh_kiov_length() cannot be zero?  I looked at
> the range_check() and there is no check for "if (*len == 0)".
> 
>     93 
>     94         to_pull = vringh_kiov_length(&vq->out_iov);
>     95 
>     96         bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &hdr,
>     97                                       sizeof(hdr));
>     98         if (bytes != sizeof(hdr)) {
>     99                 dev_err(&vdpasim->vdpa.dev, "request out header too short\n");
>     100                 return false;
>     101         }
>     102 
>     103         to_pull -= bytes;
> 
> The same "bytes" is used for both to_pull and to_push.  In this
> assignment it would only be used for the default case which prints an
> error message.
> 

Sorry, no.  This part is wrong.  "bytes" is not used for "to_push"
either here or below.  But I still am not sure "*len == 0" or how we
know that "to_push >= VIRTIO_BLK_ID_BYTES".

regards,
dan carpenter

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