irqchip/gic-v3-its: Fix comparison logic in lpi_range_cmp

Villemoes · Marc Zyngier · commit 89dc891792c2 · 2019-03-20T18:20:39.000Z
The lpi_range_list is supposed to be sorted in ascending order of ->base_id (at least if the range merging is to work), but the current comparison function returns a positive value if rb->base_id > ra->base_id, which means that list_sort() will put A after B in that case - and vice versa, of course. Fixes: 880cb3c (irqchip/gic-v3-its: Refactor LPI allocator) Cc: stable@vger.kernel.org (v4.19+) Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
@@ -1476,7 +1476,7 @@ static int lpi_range_cmp(void *priv, struct list_head *a, struct list_head *b)
 	ra = container_of(a, struct lpi_range, entry);
 	rb = container_of(b, struct lpi_range, entry);
 
-	return rb->base_id - ra->base_id;
+	return ra->base_id - rb->base_id;
 }
 
 static void merge_lpi_ranges(void)

Original file line number	Diff line number	Diff line change
`@@ -1476,7 +1476,7 @@ static int lpi_range_cmp(void priv, struct list_head a, struct list_head *b)`
`1476`	`1476`	`ra = container_of(a, struct lpi_range, entry);`
`1477`	`1477`	`rb = container_of(b, struct lpi_range, entry);`
`1478`	`1478`
`1479`		`- return rb->base_id - ra->base_id;`
	`1479`	`+ return ra->base_id - rb->base_id;`
`1480`	`1480`	`}`
`1481`	`1481`
`1482`	`1482`	`static void merge_lpi_ranges(void)`