drm/amdkfd: Simplify the mmap offset related bit operations

The new code uses straightforward bit shifts and thus has better readability.
Signed-off-by: Yong Zhao <Yong.Zhao@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

@@ -296,7 +296,6 @@ static int kfd_ioctl_create_queue(struct file *filep, struct kfd_process *p,
 	/* Return gpu_id as doorbell offset for mmap usage */
 	args->doorbell_offset = KFD_MMAP_TYPE_DOORBELL;
 	args->doorbell_offset |= KFD_MMAP_GPU_ID(args->gpu_id);
-	args->doorbell_offset <<= PAGE_SHIFT;
 	if (KFD_IS_SOC15(dev->device_info->asic_family))
 		/* On SOC15 ASICs, doorbell allocation must be
 		 * per-device, and independent from the per-process
@@ -1312,10 +1311,9 @@ static int kfd_ioctl_alloc_memory_of_gpu(struct file *filep,
 	/* MMIO is mapped through kfd device
 	 * Generate a kfd mmap offset
 	 */
-	if (flags & KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP) {
-		args->mmap_offset = KFD_MMAP_TYPE_MMIO | KFD_MMAP_GPU_ID(args->gpu_id);
-		args->mmap_offset <<= PAGE_SHIFT;
-	}
+	if (flags & KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)
+		args->mmap_offset = KFD_MMAP_TYPE_MMIO
+					| KFD_MMAP_GPU_ID(args->gpu_id);
 
 	return 0;
 
@@ -1899,20 +1897,19 @@ static int kfd_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct kfd_process *process;
 	struct kfd_dev *dev = NULL;
-	unsigned long vm_pgoff;
+	unsigned long mmap_offset;
 	unsigned int gpu_id;
 
 	process = kfd_get_process(current);
 	if (IS_ERR(process))
 		return PTR_ERR(process);
 
-	vm_pgoff = vma->vm_pgoff;
-	vma->vm_pgoff = KFD_MMAP_OFFSET_VALUE_GET(vm_pgoff);
-	gpu_id = KFD_MMAP_GPU_ID_GET(vm_pgoff);
+	mmap_offset = vma->vm_pgoff << PAGE_SHIFT;
+	gpu_id = KFD_MMAP_GET_GPU_ID(mmap_offset);
 	if (gpu_id)
 		dev = kfd_device_by_id(gpu_id);
 
-	switch (vm_pgoff & KFD_MMAP_TYPE_MASK) {
+	switch (mmap_offset & KFD_MMAP_TYPE_MASK) {
 	case KFD_MMAP_TYPE_DOORBELL:
 		if (!dev)
 			return -ENODEV;

drivers/gpu/drm/amd/amdkfd/kfd_events.c

@@ -346,7 +346,6 @@ int kfd_event_create(struct file *devkfd, struct kfd_process *p,
 		ret = create_signal_event(devkfd, p, ev);
 		if (!ret) {
 			*event_page_offset = KFD_MMAP_TYPE_EVENTS;
-			*event_page_offset <<= PAGE_SHIFT;
 			*event_slot_index = ev->event_id;
 		}
 		break;

drivers/gpu/drm/amd/amdkfd/kfd_priv.h

@@ -59,24 +59,21 @@
  * NOTE: struct vm_area_struct.vm_pgoff uses offset in pages. Hence, these
  *  defines are w.r.t to PAGE_SIZE
  */
-#define KFD_MMAP_TYPE_SHIFT	(62 - PAGE_SHIFT)
+#define KFD_MMAP_TYPE_SHIFT	62
 #define KFD_MMAP_TYPE_MASK	(0x3ULL << KFD_MMAP_TYPE_SHIFT)
 #define KFD_MMAP_TYPE_DOORBELL	(0x3ULL << KFD_MMAP_TYPE_SHIFT)
 #define KFD_MMAP_TYPE_EVENTS	(0x2ULL << KFD_MMAP_TYPE_SHIFT)
 #define KFD_MMAP_TYPE_RESERVED_MEM	(0x1ULL << KFD_MMAP_TYPE_SHIFT)
 #define KFD_MMAP_TYPE_MMIO	(0x0ULL << KFD_MMAP_TYPE_SHIFT)
 
-#define KFD_MMAP_GPU_ID_SHIFT (46 - PAGE_SHIFT)
+#define KFD_MMAP_GPU_ID_SHIFT 46
 #define KFD_MMAP_GPU_ID_MASK (((1ULL << KFD_GPU_ID_HASH_WIDTH) - 1) \
 				<< KFD_MMAP_GPU_ID_SHIFT)
 #define KFD_MMAP_GPU_ID(gpu_id) ((((uint64_t)gpu_id) << KFD_MMAP_GPU_ID_SHIFT)\
 				& KFD_MMAP_GPU_ID_MASK)
-#define KFD_MMAP_GPU_ID_GET(offset)    ((offset & KFD_MMAP_GPU_ID_MASK) \
+#define KFD_MMAP_GET_GPU_ID(offset)    ((offset & KFD_MMAP_GPU_ID_MASK) \
 				>> KFD_MMAP_GPU_ID_SHIFT)
 
-#define KFD_MMAP_OFFSET_VALUE_MASK	(0x3FFFFFFFFFFFULL >> PAGE_SHIFT)
-#define KFD_MMAP_OFFSET_VALUE_GET(offset) (offset & KFD_MMAP_OFFSET_VALUE_MASK)
-
 /*
  * When working with cp scheduler we should assign the HIQ manually or via
  * the amdgpu driver to a fixed hqd slot, here are the fixed HIQ hqd slot

drivers/gpu/drm/amd/amdkfd/kfd_process.c

@@ -560,8 +560,7 @@ static int kfd_process_init_cwsr_apu(struct kfd_process *p, struct file *filep)
 		if (!dev->cwsr_enabled || qpd->cwsr_kaddr || qpd->cwsr_base)
 			continue;
 
-		offset = (KFD_MMAP_TYPE_RESERVED_MEM | KFD_MMAP_GPU_ID(dev->id))
-			<< PAGE_SHIFT;
+		offset = KFD_MMAP_TYPE_RESERVED_MEM | KFD_MMAP_GPU_ID(dev->id);
 		qpd->tba_addr = (int64_t)vm_mmap(filep, 0,
 			KFD_CWSR_TBA_TMA_SIZE, PROT_READ | PROT_EXEC,
 			MAP_SHARED, offset);