drm/amdgpu: add interface for editing a foreign process's priority v3

The AMDGPU_SCHED_OP_PROCESS_PRIORITY_OVERRIDE ioctls are used to set
the priority of a different process in the current system.

When a request is dropped, the process's contexts will be
restored to the priority specified at context creation time.

A request can be dropped by setting the override priority to
AMDGPU_CTX_PRIORITY_UNSET.

An fd is used to identify the remote process. This is simpler than
passing a pid number, which is vulnerable to re-use, etc.

This functionality is limited to DRM_MASTER since abuse of this
interface can have a negative impact on the system's performance.

v2: removed unused output structure
v3: change refcounted interface for a regular set operation

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index d2ef24f..a78b03f6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -25,6 +25,7 @@
 #include <drm/drmP.h>
 #include <drm/drm_auth.h>
 #include "amdgpu.h"
+#include "amdgpu_sched.h"
 
 static int amdgpu_ctx_priority_permit(struct drm_file *filp,
 				      enum amd_sched_priority priority)
@@ -220,26 +221,6 @@ static int amdgpu_ctx_query(struct amdgpu_device *adev,
 	return 0;
 }
 
-static enum amd_sched_priority amdgpu_to_sched_priority(int amdgpu_priority)
-{
-	switch (amdgpu_priority) {
-	case AMDGPU_CTX_PRIORITY_HIGH_HW:
-		return AMD_SCHED_PRIORITY_HIGH_HW;
-	case AMDGPU_CTX_PRIORITY_HIGH_SW:
-		return AMD_SCHED_PRIORITY_HIGH_SW;
-	case AMDGPU_CTX_PRIORITY_NORMAL:
-		return AMD_SCHED_PRIORITY_NORMAL;
-	case AMDGPU_CTX_PRIORITY_LOW_SW:
-	case AMDGPU_CTX_PRIORITY_LOW_HW:
-		return AMD_SCHED_PRIORITY_LOW;
-	case AMDGPU_CTX_PRIORITY_UNSET:
-		return AMD_SCHED_PRIORITY_UNSET;
-	default:
-		WARN(1, "Invalid context priority %d\n", amdgpu_priority);
-		return AMD_SCHED_PRIORITY_INVALID;
-	}
-}
-
 int amdgpu_ctx_ioctl(struct drm_device *dev, void *data,
 		     struct drm_file *filp)
 {