[PATCH 7/9] drm/nouveau/pci: Move a variable assignment behind condition checks in nvkm_pcie_set_link()

[Markus Elfring]

Date: Sun, 16 Apr 2023 08:18:40 +0200

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the function “nvkm_pcie_set_link”.

Thus avoid the risk for undefined behaviour by moving the assignment
for the variable “subdev” behind some condition checks.

This issue was detected by using the Coccinelle software.

Fixes: bcc19d9bf5cd8d49428c487adced1aa101271b18 ("drm/nouveau/pci: implement generic code for pcie speed change")
Signed-off-by: Markus Elfring <elfring at users.sourceforge.net>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/pci/pcie.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/pci/pcie.c b/drivers/gpu/drm/nouveau/nvkm/subdev/pci/pcie.c
index d71e5db5028a..b295f100e1c1 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/pci/pcie.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pci/pcie.c
@@ -114,7 +114,7 @@ nvkm_pcie_init(struct nvkm_pci *pci)
 int
 nvkm_pcie_set_link(struct nvkm_pci *pci, enum nvkm_pcie_speed speed, u8 width)
 {
-	struct nvkm_subdev *subdev = &pci->subdev;
+	struct nvkm_subdev *subdev;
 	enum nvkm_pcie_speed cur_speed, max_speed;
 	struct pci_bus *pbus;
 	int ret;
@@ -126,6 +126,7 @@ nvkm_pcie_set_link(struct nvkm_pci *pci, enum nvkm_pcie_speed speed, u8 width)
 	if (!pci->func->pcie.set_link)
 		return -ENOSYS;

+	subdev = &pci->subdev;
 	nvkm_trace(subdev, "requested %s\n", nvkm_pcie_speeds[speed]);

 	if (pci->func->pcie.version(pci) < 2) {
--
2.40.0