[PATCH] brd: decrease the number of allocated pages which discarded

[long.yunjian]

From: Zhang Xianwei <zhang.xianwei8@xxxxxxxxxx>
The number of allocated pages which discarded will not decrease.
Fix it.

Fixes: 9ead7efc6f3f ("brd: implement discard support")

Signed-off-by: Zhang Xianwei <zhang.xianwei8@xxxxxxxxxx>
---
 drivers/block/brd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 5a95671d8151..292f127cae0a 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -231,8 +231,10 @@ static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size)
 	xa_lock(&brd->brd_pages);
 	while (size >= PAGE_SIZE && aligned_sector < rd_size * 2) {
 		page = __xa_erase(&brd->brd_pages, aligned_sector >> PAGE_SECTORS_SHIFT);
-		if (page)
+		if (page) {
 			__free_page(page);
+			brd->brd_nr_pages--;
+		}
 		aligned_sector += PAGE_SECTORS;
 		size -= PAGE_SIZE;
 	}
-- 
2.27.0