releases/6.12.63/resource-replace-open-coded-resource_intersection.patch

From 5ba75cb9a6faec911ad43099204df6f649285900 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Wed, 25 Sep 2024 18:43:34 +0300
Subject: resource: replace open coded resource_intersection()

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit 5c1edea773c98707fbb23d1df168bcff52f61e4b ]

Patch series "resource: A couple of cleanups".

A couple of ad-hoc cleanups since there was a recent development of
the code in question. No functional changes intended.

This patch (of 2):

__region_intersects() uses open coded resource_intersection().  Replace it
with existing API which also make more clear what we are checking.

Link: https://lkml.kernel.org/r/20240925154355.1170859-1-andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20240925154355.1170859-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 6fb3acdebf65 ("Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/resource.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 1d48ae8646352..c3e00365f8e37 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -537,17 +537,16 @@ static int __region_intersects(struct resource *parent, resource_size_t start,
 			       size_t size, unsigned long flags,
 			       unsigned long desc)
 {
-	resource_size_t ostart, oend;
 	int type = 0; int other = 0;
 	struct resource *p, *dp;
+	struct resource res, o;
 	bool is_type, covered;
-	struct resource res;
 
 	res.start = start;
 	res.end = start + size - 1;
 
 	for (p = parent->child; p ; p = p->sibling) {
-		if (!resource_overlaps(p, &res))
+		if (!resource_intersection(p, &res, &o))
 			continue;
 		is_type = (p->flags & flags) == flags &&
 			(desc == IORES_DESC_NONE || desc == p->desc);
@@ -568,8 +567,6 @@ static int __region_intersects(struct resource *parent, resource_size_t start,
 		 * |-- "System RAM" --||-- "CXL Window 0a" --|
 		 */
 		covered = false;
-		ostart = max(res.start, p->start);
-		oend = min(res.end, p->end);
 		for_each_resource(p, dp, false) {
 			if (!resource_overlaps(dp, &res))
 				continue;
@@ -578,17 +575,17 @@ static int __region_intersects(struct resource *parent, resource_size_t start,
 			if (is_type) {
 				type++;
 				/*
-				 * Range from 'ostart' to 'dp->start'
+				 * Range from 'o.start' to 'dp->start'
 				 * isn't covered by matched resource.
 				 */
-				if (dp->start > ostart)
+				if (dp->start > o.start)
 					break;
-				if (dp->end >= oend) {
+				if (dp->end >= o.end) {
 					covered = true;
 					break;
 				}
 				/* Remove covered range */
-				ostart = max(ostart, dp->end + 1);
+				o.start = max(o.start, dp->end + 1);
 			}
 		}
 		if (!covered)
-- 
2.51.0