From: "Michael S. Tsirkin" <mst@redhat.com>
To: Christophe de Dinechin <dinechin@redhat.com>
Cc: trivial@kernel.org, Ben Segall <bsegall@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>, Mel Gorman <mgorman@suse.de>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Jason Wang <jasowang@redhat.com>,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
Zhen Lei <thunder.leizhen@huawei.com>,
Juri Lelli <juri.lelli@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Subject: Re: [PATCH 3/3] virtio-pci: Use cpumask_available to fix compilation error
Date: Fri, 15 Apr 2022 04:48:52 -0400 [thread overview]
Message-ID: <20220415044657-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20220414150855.2407137-4-dinechin@redhat.com>
On Thu, Apr 14, 2022 at 05:08:55PM +0200, Christophe de Dinechin wrote:
> With GCC 12 and defconfig, we get the following error:
>
> | CC drivers/virtio/virtio_pci_common.o
> | drivers/virtio/virtio_pci_common.c: In function ‘vp_del_vqs’:
> | drivers/virtio/virtio_pci_common.c:257:29: error: the comparison will
> | always evaluate as ‘true’ for the pointer operand in
> | ‘vp_dev->msix_affinity_masks + (sizetype)((long unsigned int)i * 8)’
> | must not be NULL [-Werror=address]
> | 257 | if (vp_dev->msix_affinity_masks[i])
> | | ^~~~~~
>
> This happens in the case where CONFIG_CPUMASK_OFFSTACK is not defined,
> since we typedef cpumask_var_t as an array. The compiler is essentially
> complaining that an array pointer cannot be NULL. This is not a very
> important warning, but there is a function called cpumask_available that
> seems to be defined just for that case, so the fix is easy.
>
> Signed-off-by: Christophe de Dinechin <christophe@dinechin.org>
> Signed-off-by: Christophe de Dinechin <dinechin@redhat.com>
There was an alternate patch proposed for this by
Murilo Opsfelder Araujo. What do you think about that approach?
> ---
> drivers/virtio/virtio_pci_common.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index d724f676608b..5c44a2f13c93 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -254,7 +254,7 @@ void vp_del_vqs(struct virtio_device *vdev)
>
> if (vp_dev->msix_affinity_masks) {
> for (i = 0; i < vp_dev->msix_vectors; i++)
> - if (vp_dev->msix_affinity_masks[i])
> + if (cpumask_available(vp_dev->msix_affinity_masks[i]))
> free_cpumask_var(vp_dev->msix_affinity_masks[i]);
> }
>
> --
> 2.35.1
next prev parent reply other threads:[~2022-04-15 8:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 15:08 [PATCH 0/3] trivial: Fix several compilation errors/warnings with GCC12 Christophe de Dinechin
2022-04-14 15:08 ` [PATCH 1/3] sched/headers: Fix compilation error with GCC 12 Christophe de Dinechin
2022-04-14 15:21 ` Peter Zijlstra
2022-04-14 20:30 ` Andrew Morton
2022-04-17 15:52 ` Peter Zijlstra
2022-04-20 18:45 ` Kees Cook
2022-04-21 7:32 ` Peter Zijlstra
2022-04-25 14:23 ` Christophe de Dinechin
2022-04-17 13:27 ` David Laight
2022-04-25 14:07 ` Christophe de Dinechin
2022-05-19 11:16 ` Peter Zijlstra
2022-04-14 15:08 ` [PATCH 2/3] nodemask.h: Fix compilation error with GCC12 Christophe de Dinechin
2022-04-14 15:23 ` Peter Zijlstra
2022-04-14 15:08 ` [PATCH 3/3] virtio-pci: Use cpumask_available to fix compilation error Christophe de Dinechin
2022-04-15 8:48 ` Michael S. Tsirkin [this message]
2022-04-28 9:48 ` Christophe Marie Francois Dupont de Dinechin
2022-04-28 11:06 ` Michael S. Tsirkin
2022-05-15 21:24 ` [PATCH 0/3] trivial: Fix several compilation errors/warnings with GCC12 Davidlohr Bueso
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