[PATCH 5.14 376/849] drm/amdgpu: fix warning for overflow check

Greg Kroah-Hartman
2021-11-16T01:36:23Z

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit 335aea75b0d95518951cad7c4c676e6f1c02c150 ]

The overflow check in amdgpu_bo_list_create() causes a warning with
clang-14 on 64-bit architectures, since the limit can never be
exceeded.

drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c:74:18: error: result of comparison of constant 256204778801521549 with expression of type 'unsigned int' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
if (num_entries > (SIZE_MAX - sizeof(struct amdgpu_bo_list))
~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The check remains useful for 32-bit architectures, so just avoid the
warning by using size_t as the type for the count.

Fixes: 920990cb080a ("drm/amdgpu: allocate the bo_list array after the list")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c | 2 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
index 15c45b2a39835..714178f1b6c6e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
@@ -61,7 +61,7 @@ static void amdgpu_bo_list_free(struct kref *ref)

int amdgpu_bo_list_create(struct amdgpu_device *adev, struct drm_file *filp,
struct drm_amdgpu_bo_list_entry *info,
- unsigned num_entries, struct amdgpu_bo_list **result)
+ size_t num_entries, struct amdgpu_bo_list **result)
{
unsigned last_entry = 0, first_userptr = num_entries;
struct amdgpu_bo_list_entry *array;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
index a130e766cbdbe..529d52a204cf4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
@@ -60,7 +60,7 @@ int amdgpu_bo_create_list_entry_array(struct drm_amdgpu_bo_list_in *in,
int amdgpu_bo_list_create(struct amdgpu_device *adev,
struct drm_file *filp,
struct drm_amdgpu_bo_list_entry *info,
- unsigned num_entries,
+ size_t num_entries,
struct amdgpu_bo_list **list);

static inline struct amdgpu_bo_list_entry *
--
2.33.0