linux-kernel - [PATCH AUTOSEL for 4.14 131/135] lightnvm: pblk: protect line bitmap while submitting meta io

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Date:   Thu, 7 Dec 2017 15:46:03 +0000
From:   alexander.levin@...izon.com
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Rakesh Pandit <rakesh@...era.com>,
        Matias Bjørling <m@...rling.me>,
        Jens Axboe <axboe@...nel.dk>, alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.14 131/135] lightnvm: pblk: protect line bitmap
 while submitting meta io

From: Rakesh Pandit <rakesh@...era.com>

[ Upstream commit e57903fd972a398b7140d0bc055714e13a0e58c5 ]

It seems pblk_dealloc_page would race against pblk_alloc_pages for
line bitmap for sector allocation.The chances are very low but might
as well protect the bitmap properly.

Signed-off-by: Rakesh Pandit <rakesh@...era.com>
Reviewed-by: Javier González <javier@...xlabs.com>
Signed-off-by: Matias Bjørling <m@...rling.me>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 drivers/lightnvm/pblk-core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index bb3e9d5d4276..3f0ddc0d7393 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -486,12 +486,14 @@ void pblk_dealloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs)
 	u64 addr;
 	int i;
 
+	spin_lock(&line->lock);
 	addr = find_next_zero_bit(line->map_bitmap,
 					pblk->lm.sec_per_line, line->cur_sec);
 	line->cur_sec = addr - nr_secs;
 
 	for (i = 0; i < nr_secs; i++, line->cur_sec--)
 		WARN_ON(!test_and_clear_bit(line->cur_sec, line->map_bitmap));
+	spin_unlock(&line->lock);
 }
 
 u64 __pblk_alloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs)
-- 
2.11.0