From: Yu Kuai <yukuai3@xxxxxxxxxx>
brd_do_discard() just aligned start sector to page, this can only work
if the discard size if at least one page. For example:
blkdiscard /dev/ram0 -o 5120 -l 1024
In this case, size = (1024 - (8192 - 5120)), which is a huge value.
Fix the problem by round_down() the end sector.
Fixes: 9ead7efc6f3f ("brd: implement discard support")
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/block/brd.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 2753fb21410b..a3725673cf16 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -167,18 +167,21 @@ static void brd_free_one_page(struct rcu_head *head)
static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size)
{
sector_t aligned_sector = round_up(sector, PAGE_SECTORS);
+ sector_t aligned_end = round_down(
+ sector + (size >> SECTOR_SHIFT), PAGE_SECTORS);
struct page *page;
- size -= (aligned_sector - sector) * SECTOR_SIZE;
+ if (aligned_end <= aligned_sector)
+ return;
+
xa_lock(&brd->brd_pages);
- while (size >= PAGE_SIZE && aligned_sector < rd_size * 2) {
+ while (aligned_sector < aligned_end && aligned_sector < rd_size * 2) {
page = __xa_erase(&brd->brd_pages, aligned_sector >> PAGE_SECTORS_SHIFT);
if (page) {
call_rcu(&page->rcu_head, brd_free_one_page);
brd->brd_nr_pages--;
}
aligned_sector += PAGE_SECTORS;
- size -= PAGE_SIZE;
}
xa_unlock(&brd->brd_pages);
}
--
2.39.2
