[PATCH 4.19 21/45] irqchip/gic-v3-its: Fix comparison logic in lpi_range_cmp

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>

commit 89dc891792c2e046b030f87600109c22209da32e upstream.

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: 880cb3cddd16 (irqchip/gic-v3-its: Refactor LPI allocator)
Cc: stable@xxxxxxxxxxxxxxx (v4.19+)
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/irqchip/irq-gic-v3-its.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1477,7 +1477,7 @@ static int lpi_range_cmp(void *priv, str
 	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)