linux-kernel - [PATCH AUTOSEL 4.20 164/304] lightnvm: pblk: fix resubmission of overwritten write err lbas

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Message-Id: <20190128154341.47195-164-sashal@kernel.org>
Date:   Mon, 28 Jan 2019 10:41:21 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Hans Holmberg <hans.holmberg@...xlabs.com>,
        Matias Bjørling <mb@...htnvm.io>,
        Jens Axboe <axboe@...nel.dk>, Sasha Levin <sashal@...nel.org>,
        linux-block@...r.kernel.org
Subject: [PATCH AUTOSEL 4.20 164/304] lightnvm: pblk: fix resubmission of overwritten write err lbas

From: Hans Holmberg <hans.holmberg@...xlabs.com>

[ Upstream commit c12fa401ac8c94a74aff68bb5736b3f1dc695fa8 ]

Make sure we only look up valid lba addresses on the resubmission path.

If an lba is invalidated in the write buffer, that sector will be
submitted to disk (as it is already mapped to a ppa), and that write
might fail, resulting in a crash when trying to look up the lba in the
mapping table (as the lba is marked as invalid).

Signed-off-by: Hans Holmberg <hans.holmberg@...xlabs.com>
Reviewed-by: Javier González <javier@...igon.com>
Signed-off-by: Matias Bjørling <mb@...htnvm.io>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/lightnvm/pblk-write.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
index fa8726493b39..3ddd16f47106 100644
--- a/drivers/lightnvm/pblk-write.c
+++ b/drivers/lightnvm/pblk-write.c
@@ -148,9 +148,11 @@ static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
 		w_ctx = &entry->w_ctx;
 
 		/* Check if the lba has been overwritten */
-		ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
-		if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
-			w_ctx->lba = ADDR_EMPTY;
+		if (w_ctx->lba != ADDR_EMPTY) {
+			ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
+			if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
+				w_ctx->lba = ADDR_EMPTY;
+		}
 
 		/* Mark up the entry as submittable again */
 		flags = READ_ONCE(w_ctx->flags);
-- 
2.19.1