linux-kernel - [PATCH AUTOSEL for 4.14 126/135] lightnvm: pblk: prevent gc kicks when gc is not operational

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Date:   Thu, 7 Dec 2017 15:46:02 +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:     Hans Holmberg <hans.holmberg@...xlabs.com>,
        Matias Bjørling <m@...rling.me>,
        Jens Axboe <axboe@...nel.dk>, alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.14 126/135] lightnvm: pblk: prevent gc kicks
 when gc is not operational

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

[ Upstream commit 3e3a5b8ebd5d3b1d68facc58b0674a2564653222 ]

GC can be kicked after it has been shut down when closing the last
line during exit, resulting in accesses to freed structures.

Make sure that GC is not triggered while it is not operational.
Also make sure that GC won't be re-activated during exit when
running on another processor by using timer_del_sync.

Signed-off-by: Hans Holmberg <hans.holmberg@...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-gc.c   | 9 +++++----
 drivers/lightnvm/pblk-init.c | 1 +
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
index 6090d28f7995..d6bae085e1d2 100644
--- a/drivers/lightnvm/pblk-gc.c
+++ b/drivers/lightnvm/pblk-gc.c
@@ -486,10 +486,10 @@ void pblk_gc_should_start(struct pblk *pblk)
 {
 	struct pblk_gc *gc = &pblk->gc;
 
-	if (gc->gc_enabled && !gc->gc_active)
+	if (gc->gc_enabled && !gc->gc_active) {
 		pblk_gc_start(pblk);
-
-	pblk_gc_kick(pblk);
+		pblk_gc_kick(pblk);
+	}
 }
 
 /*
@@ -628,7 +628,8 @@ void pblk_gc_exit(struct pblk *pblk)
 	flush_workqueue(gc->gc_reader_wq);
 	flush_workqueue(gc->gc_line_reader_wq);
 
-	del_timer(&gc->gc_timer);
+	gc->gc_enabled = 0;
+	del_timer_sync(&gc->gc_timer);
 	pblk_gc_stop(pblk, 1);
 
 	if (gc->gc_ts)
diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index 1b0f61233c21..1a01f201e9e7 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -923,6 +923,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
 	pblk->dev = dev;
 	pblk->disk = tdisk;
 	pblk->state = PBLK_STATE_RUNNING;
+	pblk->gc.gc_enabled = 0;
 
 	spin_lock_init(&pblk->trans_lock);
 	spin_lock_init(&pblk->lock);
-- 
2.11.0