resource: replace open coded resource_intersection()

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>

diff --git a/kernel/resource.c b/kernel/resource.c
index 4101016..1c77ac2 100644 (file)
--- 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)