drm/xe: Misc refine for svm

These changes should have no functional impact.
1. Correct typo of "operation"in macro range_debug().
2. Combine 2 spin_lock() call in xe_svm_garbage_collector() into 1.
3. Drop redundant preferred_region_is_vram check in
   xe_svm_range_needs_migrate_to_vram().
4. Combine the devmem_possible check in xe_svm_handle_pagefault().
   need_vram includes the IS_DGFX() check, so there is no change for
   .devmem_only.

v2: revert !ctx.devmem_only change (Matt)
v3: rebase code and refine commit message.
v4: rebase code and refine commit message.

Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20250911031405.1371812-2-shuicheng.lin@intel.com

Author: ShuichengLin

drivers/gpu/drm/xe/xe_svm.c

@@ -50,11 +50,11 @@ static struct xe_vm *range_to_vm(struct drm_gpusvm_range *r)
 	return gpusvm_to_vm(r->gpusvm);
 }
 
-#define range_debug(r__, operaton__)					\
+#define range_debug(r__, operation__)					\
 	vm_dbg(&range_to_vm(&(r__)->base)->xe->drm,			\
 	       "%s: asid=%u, gpusvm=%p, vram=%d,%d, seqno=%lu, " \
 	       "start=0x%014lx, end=0x%014lx, size=%lu",		\
-	       (operaton__), range_to_vm(&(r__)->base)->usm.asid,	\
+	       (operation__), range_to_vm(&(r__)->base)->usm.asid,	\
 	       (r__)->base.gpusvm,					\
 	       xe_svm_range_in_vram((r__)) ? 1 : 0,			\
 	       xe_svm_range_has_vram_binding((r__)) ? 1 : 0,		\
@@ -347,8 +347,8 @@ static int xe_svm_garbage_collector(struct xe_vm *vm)
 	if (xe_vm_is_closed_or_banned(vm))
 		return -ENOENT;
 
-	spin_lock(&vm->svm.garbage_collector.lock);
 	for (;;) {
+		spin_lock(&vm->svm.garbage_collector.lock);
 		range = list_first_entry_or_null(&vm->svm.garbage_collector.range_list,
 						 typeof(*range),
 						 garbage_collector_link);
@@ -377,8 +377,6 @@ static int xe_svm_garbage_collector(struct xe_vm *vm)
 			else
 				return err;
 		}
-
-		spin_lock(&vm->svm.garbage_collector.lock);
 	}
 	spin_unlock(&vm->svm.garbage_collector.lock);
 
@@ -944,12 +942,12 @@ bool xe_svm_range_needs_migrate_to_vram(struct xe_svm_range *range, struct xe_vm
 
 	xe_assert(vm->xe, IS_DGFX(vm->xe));
 
-	if (preferred_region_is_vram && xe_svm_range_in_vram(range)) {
+	if (xe_svm_range_in_vram(range)) {
 		drm_info(&vm->xe->drm, "Range is already in VRAM\n");
 		return false;
 	}
 
-	if (preferred_region_is_vram && range_size < SZ_64K && !supports_4K_migration(vm->xe)) {
+	if (range_size < SZ_64K && !supports_4K_migration(vm->xe)) {
 		drm_dbg(&vm->xe->drm, "Platform doesn't support SZ_4K range migration\n");
 		return false;
 	}
@@ -1010,15 +1008,14 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
 				     struct xe_gt *gt, u64 fault_addr,
 				     bool need_vram)
 {
+	int devmem_possible = IS_DGFX(vm->xe) &&
+		IS_ENABLED(CONFIG_DRM_XE_PAGEMAP);
 	struct drm_gpusvm_ctx ctx = {
 		.read_only = xe_vma_read_only(vma),
-		.devmem_possible = IS_DGFX(vm->xe) &&
-			IS_ENABLED(CONFIG_DRM_XE_PAGEMAP),
-		.check_pages_threshold = IS_DGFX(vm->xe) &&
-			IS_ENABLED(CONFIG_DRM_XE_PAGEMAP) ? SZ_64K : 0,
-		.devmem_only = need_vram && IS_ENABLED(CONFIG_DRM_XE_PAGEMAP),
-		.timeslice_ms = need_vram && IS_DGFX(vm->xe) &&
-			IS_ENABLED(CONFIG_DRM_XE_PAGEMAP) ?
+		.devmem_possible = devmem_possible,
+		.check_pages_threshold = devmem_possible ? SZ_64K : 0,
+		.devmem_only = need_vram && devmem_possible,
+		.timeslice_ms = need_vram && devmem_possible ?
 			vm->xe->atomic_svm_timeslice_ms : 0,
 	};
 	struct xe_validation_ctx vctx;