From: Amit Prakash Shukla <amitprakashs@marvell.com>
To: Ruifeng Wang <Ruifeng.Wang@arm.com>,
Maxime Coquelin <maxime.coquelin@redhat.com>,
Chenbo Xia <chenbo.xia@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
Jerin Jacob Kollanukkaran <jerinj@marvell.com>,
"stable@dpdk.org" <stable@dpdk.org>, nd <nd@arm.com>
Subject: RE: [PATCH] vhost: compilation fix for GCC-12
Date: Fri, 2 Sep 2022 11:57:15 +0000 [thread overview]
Message-ID: <PH0PR18MB5167CDD2477B2DABA0225D49C87A9@PH0PR18MB5167.namprd18.prod.outlook.com> (raw)
In-Reply-To: <AS8PR08MB7080E0056C9826A40F7E1EFC9E7A9@AS8PR08MB7080.eurprd08.prod.outlook.com>
Thanks Ruifeng for the code review and feedback. Please find my response inline.
> -----Original Message-----
> From: Ruifeng Wang <Ruifeng.Wang@arm.com>
> Sent: Friday, September 2, 2022 12:54 PM
> To: Amit Prakash Shukla <amitprakashs@marvell.com>; Maxime Coquelin
> <maxime.coquelin@redhat.com>; Chenbo Xia <chenbo.xia@intel.com>
> Cc: dev@dpdk.org; Jerin Jacob Kollanukkaran <jerinj@marvell.com>;
> stable@dpdk.org; nd <nd@arm.com>
> Subject: [EXT] RE: [PATCH] vhost: compilation fix for GCC-12
>
> External Email
>
> ----------------------------------------------------------------------
> > -----Original Message-----
> > From: Amit Prakash Shukla <amitprakashs@marvell.com>
> > Sent: Thursday, September 1, 2022 4:50 PM
> > To: Maxime Coquelin <maxime.coquelin@redhat.com>; Chenbo Xia
> > <chenbo.xia@intel.com>
> > Cc: dev@dpdk.org; jerinj@marvell.com; stable@dpdk.org; Amit Prakash
> > Shukla <amitprakashs@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: stable@dpdk.org
> >
> > Signed-off-by: Amit Prakash Shukla <amitprakashs@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?
Apologies for the wrong wordings in the comment. In the comment I mean, it seems like
point at which sizeof gets evaluated during compilation has changed. I am not sure on it though.
I too could not find documentation regarding the same.
>
> > + */
> > + if (unlikely(size == 0))
> > + return -1;
> > +
> > while (size > 0) {
> Change 'while(){}' to 'do{}while()' can be a simpler solution. What do you
> think?
I agree, solution suggested by you is better than the one in patch. I will make the suggested
changes as part of v2. Thanks.
>
> 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
next prev parent reply other threads:[~2022-09-02 11:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 8:49 Amit Prakash Shukla
2022-09-02 7:23 ` Ruifeng Wang
2022-09-02 11:57 ` Amit Prakash Shukla [this message]
2022-09-02 12:41 ` [PATCH v2] " Amit Prakash Shukla
2022-09-02 12:56 ` Bagas Sanjaya
2022-09-02 15:11 ` [EXT] " Amit Prakash Shukla
2022-09-02 15:06 ` [PATCH v3] " Amit Prakash Shukla
2022-10-06 7:22 ` Amit Prakash Shukla
2022-10-06 7:24 ` Maxime Coquelin
2022-10-06 8:05 ` [EXT] " Amit Prakash Shukla
2022-10-06 12:35 ` David Marchand
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