drm/amdgpu: restrict the sched jobs number to power of two

Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
CC: stable@vger.kernel.org

2 files changed, 11 insertions, 2 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index ee121ec2917b..17d1fb12128a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -252,7 +252,7 @@ uint64_t amdgpu_ctx_add_fence(struct amdgpu_ctx *ctx, struct amdgpu_ring *ring,
         unsigned idx = 0;
         struct fence *other = NULL;
 
-        idx = seq % amdgpu_sched_jobs;
+        idx = seq & (amdgpu_sched_jobs - 1);
         other = cring->fences[idx];
         if (other) {
                 signed long r;
@@ -292,7 +292,7 @@ struct fence *amdgpu_ctx_get_fence(struct amdgpu_ctx *ctx,
                 return NULL;
         }
 
-        fence = fence_get(cring->fences[seq % amdgpu_sched_jobs]);
+        fence = fence_get(cring->fences[seq & (amdgpu_sched_jobs - 1)]);
         spin_unlock(&ctx->ring_lock);
 
         return fence;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 54af6ce7901f..587ff7145361 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -949,6 +949,15 @@ static bool amdgpu_check_pot_argument(int arg)
  */
 static void amdgpu_check_arguments(struct amdgpu_device *adev)
 {
+        if (amdgpu_sched_jobs < 4) {
+                dev_warn(adev->dev, "sched jobs (%d) must be at least 4\n",
+                         amdgpu_sched_jobs);
+                amdgpu_sched_jobs = 4;
+        } else if (!amdgpu_check_pot_argument(amdgpu_sched_jobs)){
+                dev_warn(adev->dev, "sched jobs (%d) must be a power of 2\n",
+                         amdgpu_sched_jobs);
+                amdgpu_sched_jobs = roundup_pow_of_two(amdgpu_sched_jobs);
+        }
         /* vramlimit must be a power of two */
         if (!amdgpu_check_pot_argument(amdgpu_vram_limit)) {
                 dev_warn(adev->dev, "vram limit (%d) must be a power of 2\n",