drm/xe: Rename lookup_vma function to xe_find_vma_by_addr

This update renames the lookup_vma function to xe_vm_find_vma_by_addr and
makes it accessible externally. The function, which looks up a VMA by
its address within a specified VM, will be utilized in upcoming patches.

v2
 - Fix doc

Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://lore.kernel.org/r/20250513040228.470682-9-himal.prasad.ghimiray@intel.com
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>

drivers/gpu/drm/xe/xe_gt_pagefault.c

@@ -72,28 +72,6 @@ static bool vma_is_valid(struct xe_tile *tile, struct xe_vma *vma)
 		!(BIT(tile->id) & vma->tile_invalidated);
 }
 
-static bool vma_matches(struct xe_vma *vma, u64 page_addr)
-{
-	if (page_addr > xe_vma_end(vma) - 1 ||
-	    page_addr + SZ_4K - 1 < xe_vma_start(vma))
-		return false;
-
-	return true;
-}
-
-static struct xe_vma *lookup_vma(struct xe_vm *vm, u64 page_addr)
-{
-	struct xe_vma *vma = NULL;
-
-	if (vm->usm.last_fault_vma) {   /* Fast lookup */
-		if (vma_matches(vm->usm.last_fault_vma, page_addr))
-			vma = vm->usm.last_fault_vma;
-	}
-	if (!vma)
-		vma = xe_vm_find_overlapping_vma(vm, page_addr, SZ_4K);
-
-	return vma;
-}
 
 static int xe_pf_begin(struct drm_exec *exec, struct xe_vma *vma,
 		       bool atomic, unsigned int id)
@@ -231,7 +209,7 @@ static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf)
 		goto unlock_vm;
 	}
 
-	vma = lookup_vma(vm, pf->page_addr);
+	vma = xe_vm_find_vma_by_addr(vm, pf->page_addr);
 	if (!vma) {
 		err = -EINVAL;
 		goto unlock_vm;

drivers/gpu/drm/xe/xe_vm.c

@@ -2139,6 +2139,35 @@ int xe_vm_destroy_ioctl(struct drm_device *dev, void *data,
 	return err;
 }
 
+static bool vma_matches(struct xe_vma *vma, u64 page_addr)
+{
+	if (page_addr > xe_vma_end(vma) - 1 ||
+	    page_addr + SZ_4K - 1 < xe_vma_start(vma))
+		return false;
+
+	return true;
+}
+
+/**
+ * xe_vm_find_vma_by_addr() - Find a VMA by its address
+ *
+ * @vm: the xe_vm the vma belongs to
+ * @page_addr: address to look up
+ */
+struct xe_vma *xe_vm_find_vma_by_addr(struct xe_vm *vm, u64 page_addr)
+{
+	struct xe_vma *vma = NULL;
+
+	if (vm->usm.last_fault_vma) {   /* Fast lookup */
+		if (vma_matches(vm->usm.last_fault_vma, page_addr))
+			vma = vm->usm.last_fault_vma;
+	}
+	if (!vma)
+		vma = xe_vm_find_overlapping_vma(vm, page_addr, SZ_4K);
+
+	return vma;
+}
+
 static const u32 region_to_mem_type[] = {
 	XE_PL_TT,
 	XE_PL_VRAM0,

drivers/gpu/drm/xe/xe_vm.h

@@ -169,6 +169,8 @@ static inline bool xe_vma_is_userptr(struct xe_vma *vma)
 		!xe_vma_is_cpu_addr_mirror(vma);
 }
 
+struct xe_vma *xe_vm_find_vma_by_addr(struct xe_vm *vm, u64 page_addr);
+
 /**
  * to_userptr_vma() - Return a pointer to an embedding userptr vma
  * @vma: Pointer to the embedded struct xe_vma