[PATCH 5.18 133/141] virtio-pci: Remove wrong address verification in vp_del_vqs()

Greg Kroah-Hartman
2022-06-20T13:07:28Z

From: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>

commit 7e415282b41bf0d15c6e0fe268f822d9b083f2f7 upstream.

GCC 12 enhanced -Waddress when comparing array address to null [0],
which warns:

drivers/virtio/virtio_pci_common.c: In function ‘vp_del_vqs’:
drivers/virtio/virtio_pci_common.c:257:29: warning: the comparison will always evaluate as ‘true’ for the pointer operand in ‘vp_dev->msix_affinity_masks + (sizetype)((long unsigned int)i * 256)’ must not be NULL [-Waddress]
257 | if (vp_dev->msix_affinity_masks[i])
| ^~~~~~

In fact, the verification is comparing the result of a pointer
arithmetic, the address "msix_affinity_masks + i", which will always
evaluate to true.

Under the hood, free_cpumask_var() calls kfree(), which is safe to pass
NULL, not requiring non-null verification. So remove the verification
to make compiler happy (happy compiler, happy life).

[0] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102103

Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Message-Id: <20220415023002.49805-1-muriloo@linux.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Christophe de Dinechin <dinechin@redhat.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/virtio/virtio_pci_common.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -254,8 +254,7 @@ void vp_del_vqs(struct virtio_device *vd

if (vp_dev->msix_affinity_masks) {
for (i = 0; i < vp_dev->msix_vectors; i++)
- if (vp_dev->msix_affinity_masks[i])
- free_cpumask_var(vp_dev->msix_affinity_masks[i]);
+ free_cpumask_var(vp_dev->msix_affinity_masks[i]);
}

if (vp_dev->msix_enabled) {