diff options
| author | Srinivasan Shanmugam <srinivasan.shanmugam@amd.com> | 2023-08-04 08:46:41 +0300 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2023-08-30 22:51:17 +0300 |
| commit | bf227a4f0558320513b86c279996021480f9e750 (patch) | |
| tree | daf32c9e6e4e6143165ea41b1263c096d31b1b0d | |
| parent | 4d5dc6260c2d00d603ae9c4ab452b6b4587f0d9f (diff) | |
| download | linux-bf227a4f0558320513b86c279996021480f9e750.tar.xz | |
drm/amdgpu: Use READ_ONCE() when reading the values in 'sdma_v4_4_2_ring_get_rptr'
Use READ_ONCE() instead of declaring the pointer volatile. To prevent
the compiler from refetching or reordering the read, so that the read
value is always consistent.
Link: https://lwn.net/Articles/624126/
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Guchun Chen <guchun.chen@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Le Ma <le.ma@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Le Ma <le.ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
| -rw-r--r-- | drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c b/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c index f413898dda37..267c1b7b8dcd 100644 --- a/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c +++ b/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c @@ -154,13 +154,13 @@ static int sdma_v4_4_2_init_microcode(struct amdgpu_device *adev) */ static uint64_t sdma_v4_4_2_ring_get_rptr(struct amdgpu_ring *ring) { - u64 *rptr; + u64 rptr; /* XXX check if swapping is necessary on BE */ - rptr = ((u64 *)&ring->adev->wb.wb[ring->rptr_offs]); + rptr = READ_ONCE(*((u64 *)&ring->adev->wb.wb[ring->rptr_offs])); - DRM_DEBUG("rptr before shift == 0x%016llx\n", *rptr); - return ((*rptr) >> 2); + DRM_DEBUG("rptr before shift == 0x%016llx\n", rptr); + return rptr >> 2; } /** |