From a26a339a654b9403f0ee1004f1db4c2b2a355460 Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Tue, 6 May 2025 14:17:56 +0800 Subject: [PATCH] brd: fix discard end sector 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 Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250506061756.2970934-4-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe --- 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); } -- 2.50.1