x86/mm/pat: Do not pass 'rb_root' down the memtype tree helper functions

Get rid of the passing the rb_root down the helper calls; there
is only one: &memtype_rbroot.

No change in functionality.

[ mingo: Fixed the changelog which described a different version of the patch. ]
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20191121011601.20611-3-dave@stgolabs.netSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/mm/pat_rbtree.c

@@ -52,12 +52,11 @@ enum {
 	MEMTYPE_END_MATCH	= 1
 };
 
-static struct memtype *memtype_match(struct rb_root_cached *root,
-				     u64 start, u64 end, int match_type)
+static struct memtype *memtype_match(u64 start, u64 end, int match_type)
 {
 	struct memtype *match;
 
-	match = memtype_interval_iter_first(root, start, end);
+	match = memtype_interval_iter_first(&memtype_rbroot, start, end);
 	while (match != NULL && match->start < end) {
 		if ((match_type == MEMTYPE_EXACT_MATCH) &&
 		    (match->start == start) && (match->end == end))
@@ -73,10 +72,9 @@ static struct memtype *memtype_match(struct rb_root_cached *root,
 	return NULL; /* Returns NULL if there is no match */
 }
 
-static int memtype_rb_check_conflict(struct rb_root_cached *root,
-				u64 start, u64 end,
-				enum page_cache_mode reqtype,
-				enum page_cache_mode *newtype)
+static int memtype_check_conflict(u64 start, u64 end,
+				  enum page_cache_mode reqtype,
+				  enum page_cache_mode *newtype)
 {
 	struct memtype *match;
 	enum page_cache_mode found_type = reqtype;
@@ -116,8 +114,7 @@ int rbt_memtype_check_insert(struct memtype *new,
 {
 	int err = 0;
 
-	err = memtype_rb_check_conflict(&memtype_rbroot, new->start, new->end,
-					new->type, ret_type);
+	err = memtype_check_conflict(new->start, new->end, new->type, ret_type);
 	if (err)
 		return err;
 
@@ -139,11 +136,9 @@ struct memtype *rbt_memtype_erase(u64 start, u64 end)
 	 * it then checks with END_MATCH, i.e. shrink the size of a node
 	 * from the end for the mremap case.
 	 */
-	data = memtype_match(&memtype_rbroot, start, end,
-			     MEMTYPE_EXACT_MATCH);
+	data = memtype_match(start, end, MEMTYPE_EXACT_MATCH);
 	if (!data) {
-		data = memtype_match(&memtype_rbroot, start, end,
-				     MEMTYPE_END_MATCH);
+		data = memtype_match(start, end, MEMTYPE_END_MATCH);
 		if (!data)
 			return ERR_PTR(-EINVAL);
 	}