linux-kernel - [GIT PULL 1/2] lightnvm: pblk: fix freeing of merged pages

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Message-Id: <20190621091200.23168-2-mb@lightnvm.io>
Date:   Fri, 21 Jun 2019 11:11:59 +0200
From:   Matias Bjørling <mb@...htnvm.io>
To:     axboe@...com
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        Heiner Litz <hlitz@...c.edu>,
        Matias Bjørling <mb@...htnvm.io>
Subject: [GIT PULL 1/2] lightnvm: pblk: fix freeing of merged pages

From: Heiner Litz <hlitz@...c.edu>

bio_add_pc_page() may merge pages when a bio is padded due to a flush.
Fix iteration over the bio to free the correct pages in case of a merge.

Signed-off-by: Heiner Litz <hlitz@...c.edu>
Reviewed-by: Javier González <javier@...igon.com>
Signed-off-by: Matias Bjørling <mb@...htnvm.io>
---
 drivers/lightnvm/pblk-core.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 773537804319..f546e6f28b8a 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -323,14 +323,16 @@ void pblk_free_rqd(struct pblk *pblk, struct nvm_rq *rqd, int type)
 void pblk_bio_free_pages(struct pblk *pblk, struct bio *bio, int off,
 			 int nr_pages)
 {
-	struct bio_vec bv;
-	int i;
+	struct bio_vec *bv;
+	struct page *page;
+	int i, e, nbv = 0;
 
-	WARN_ON(off + nr_pages != bio->bi_vcnt);
-
-	for (i = off; i < nr_pages + off; i++) {
-		bv = bio->bi_io_vec[i];
-		mempool_free(bv.bv_page, &pblk->page_bio_pool);
+	for (i = 0; i < bio->bi_vcnt; i++) {
+		bv = &bio->bi_io_vec[i];
+		page = bv->bv_page;
+		for (e = 0; e < bv->bv_len; e += PBLK_EXPOSED_PAGE_SIZE, nbv++)
+			if (nbv >= off)
+				mempool_free(page++, &pblk->page_bio_pool);
 	}
 }
 
-- 
2.19.1