1 files changed, 31 insertions, 30 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index db29df1ae92f..75d396b9b666 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -26,7 +26,6 @@
 #include <linux/interrupt.h>
 #include <linux/irqdomain.h>
 #include <linux/list.h>
-#include <linux/list_sort.h>
 #include <linux/log2.h>
 #include <linux/memblock.h>
 #include <linux/mm.h>
@@ -1474,31 +1473,6 @@ static struct lpi_range *mk_lpi_range(u32 base, u32 span)
 	return range;
 }
 
-static int lpi_range_cmp(void *priv, struct list_head *a, struct list_head *b)
-{
-	struct lpi_range *ra, *rb;
-
-	ra = container_of(a, struct lpi_range, entry);
-	rb = container_of(b, struct lpi_range, entry);
-
-	return ra->base_id - rb->base_id;
-}
-
-static void merge_lpi_ranges(void)
-{
-	struct lpi_range *range, *tmp;
-
-	list_for_each_entry_safe(range, tmp, &lpi_range_list, entry) {
-		if (!list_is_last(&range->entry, &lpi_range_list) &&
-		    (tmp->base_id == (range->base_id + range->span))) {
-			tmp->base_id = range->base_id;
-			tmp->span += range->span;
-			list_del(&range->entry);
-			kfree(range);
-		}
-	}
-}
-
 static int alloc_lpi_range(u32 nr_lpis, u32 *base)
 {
 	struct lpi_range *range, *tmp;
@@ -1528,9 +1502,21 @@ static int alloc_lpi_range(u32 nr_lpis, u32 *base)
 	return err;
 }
 
+static void merge_lpi_ranges(struct lpi_range *a, struct lpi_range *b)
+{
+	if (&a->entry == &lpi_range_list || &b->entry == &lpi_range_list)
+		return;
+	if (a->base_id + a->span != b->base_id)
+		return;
+	b->base_id = a->base_id;
+	b->span += a->span;
+	list_del(&a->entry);
+	kfree(a);
+}
+
 static int free_lpi_range(u32 base, u32 nr_lpis)
 {
-	struct lpi_range *new;
+	struct lpi_range *new, *old;
 
 	new = mk_lpi_range(base, nr_lpis);
 	if (!new)
@@ -1538,9 +1524,24 @@ static int free_lpi_range(u32 base, u32 nr_lpis)
 
 	mutex_lock(&lpi_range_lock);
 
-	list_add(&new->entry, &lpi_range_list);
-	list_sort(NULL, &lpi_range_list, lpi_range_cmp);
-	merge_lpi_ranges();
+	list_for_each_entry_reverse(old, &lpi_range_list, entry) {
+		if (old->base_id < base)
+			break;
+	}
+	/*
+	 * old is the last element with ->base_id smaller than base,
+	 * so new goes right after it. If there are no elements with
+	 * ->base_id smaller than base, &old->entry ends up pointing
+	 * at the head of the list, and inserting new it the start of
+	 * the list is the right thing to do in that case as well.
+	 */
+	list_add(&new->entry, &old->entry);
+	/*
+	 * Now check if we can merge with the preceding and/or
+	 * following ranges.
+	 */
+	merge_lpi_ranges(old, new);
+	merge_lpi_ranges(new, list_next_entry(new, entry));
 
 	mutex_unlock(&lpi_range_lock);
 	return 0;