linux-kernel - [PATCH 2/6] lightnvm: pblk: protect line bitmap while submitting meta io

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Message-ID: <20170921112620.GA28524@dhcp-216.srv.tuxera.com>
Date:   Thu, 21 Sep 2017 14:26:22 +0300
From:   Rakesh Pandit <rakesh@...era.com>
To:     Matias Bjørling <mb@...htnvm.io>,
        <linux-block@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     Javier González <jg@...htnvm.io>
Subject: [PATCH 2/6] lightnvm: pblk: protect line bitmap while submitting
 meta io

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.  It's not even in fast path.

Signed-off-by: Rakesh Pandit <rakesh@...era.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 a230125..b92eabc 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -502,12 +502,14 @@ 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_lock(&line->lock);
 }
 
 u64 __pblk_alloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs)
-- 
2.5.0