Re: [PATCH 3/7] virtiofsd: Use iov_discard_front() to skip bytes

[Dr. David Alan Gilbert]

* Vivek Goyal (vgoyal@redhat.com) wrote:
> There are places where we need to skip few bytes from front of the iovec
> array. We have our own custom code for that. Looks like iov_discard_front()
> can do same thing. So use that helper instead.
> 
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>

Oh nice; I hadn't noticed that file; I bet there are loads of other
places that can use it (and I still don't get why iov functions aren't
part of libc)


Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  tools/virtiofsd/fuse_virtio.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
> index 5dcd08fccb..d56b225800 100644
> --- a/tools/virtiofsd/fuse_virtio.c
> +++ b/tools/virtiofsd/fuse_virtio.c
> @@ -389,23 +389,15 @@ int virtio_send_data_iov(struct fuse_session *se, 
> struct fuse_chan *ch,
>      memcpy(in_sg_cpy, in_sg, sizeof(struct iovec) * in_num);
>      /* These get updated as we skip */
>      struct iovec *in_sg_ptr = in_sg_cpy;
> -    int in_sg_cpy_count = in_num;
> +    unsigned int in_sg_cpy_count = in_num;
>  
>      /* skip over parts of in_sg that contained the header iov */
>      size_t skip_size = iov_len;
>  
>      size_t in_sg_left = 0;
>      do {
> -        while (skip_size != 0 && in_sg_cpy_count) {
> -            if (skip_size >= in_sg_ptr[0].iov_len) {
> -                skip_size -= in_sg_ptr[0].iov_len;
> -                in_sg_ptr++;
> -                in_sg_cpy_count--;
> -            } else {
> -                in_sg_ptr[0].iov_len -= skip_size;
> -                in_sg_ptr[0].iov_base += skip_size;
> -                break;
> -            }
> +        if (skip_size != 0) {
> +         iov_discard_front(&in_sg_ptr, &in_sg_cpy_count, skip_size);
>          }
>  
>          int i;
> -- 
> 2.25.4
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK