> -----Original Message-----
> From: Amit Prakash Shukla <amitpraka...@marvell.com>
> Sent: Thursday, September 1, 2022 4:50 PM
> To: Maxime Coquelin <maxime.coque...@redhat.com>; Chenbo Xia
> <chenbo....@intel.com>
> Cc: dev@dpdk.org; jer...@marvell.com; sta...@dpdk.org; Amit Prakash Shukla
> <amitpraka...@marvell.com>
> Subject: [PATCH] vhost: compilation fix for GCC-12
>
> ../lib/vhost/virtio_net.c:941:35: error:
> 'buf_vec[0].buf_len' may be used uninitialized
> [-Werror=maybe-uninitialized]
> 941 | buf_len = buf_vec[vec_idx].buf_len;
> | ~~~~~~~~~~~~~~~~^~~~~~~~
> ../lib/vhost/virtio_net.c: In function 'virtio_dev_rx_packed':
> ../lib/vhost/virtio_net.c:1285:27: note: 'buf_vec' declared here
> 1285 | struct buf_vector buf_vec[BUF_VECTOR_MAX];
> | ^~~~~~~
> cc1: all warnings being treated as errors
>
> Fixes: 93520085efda ("vhost: add packed ring single enqueue")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Amit Prakash Shukla <amitpraka...@marvell.com>
> ---
> lib/vhost/virtio_net.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index
> b3d954aab4..0220bc923c
> 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -1069,6 +1069,12 @@ vhost_enqueue_single_packed(struct virtio_net *dev,
> else
> max_tries = 1;
>
> + /* To avoid GCC-12 warning.
> + * GCC-12 is not evaluating sizeof at compile time.
Is this a compiler behavior change against previous versions?
I tried to find some clue from gcc-12 doc but got nothing. Can you point me to
any material?
> + */
> + if (unlikely(size == 0))
> + return -1;
> +
> while (size > 0) {
Change 'while(){}' to 'do{}while()' can be a simpler solution. What do you
think?
Thanks.
> /*
> * if we tried all available ring items, and still @@ -1574,6
> +1580,12 @@
> vhost_enqueue_async_packed(struct virtio_net *dev,
> else
> max_tries = 1;
>
> + /* To avoid GCC-12 warning.
> + * GCC-12 is not evaluating sizeof at compile time.
> + */
> + if (unlikely(size == 0))
> + return -1;
> +
> while (size > 0) {
> /*
> * if we tried all available ring items, and still
> --
> 2.25.1
