linux-kernel - [PATCH] blkcg: put module reference

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Message-ID: <c47cf22b3f041213c765ea5fd65901e4eb397f0a.1452552094.git.shli@fb.com>
Date:	Mon, 11 Jan 2016 14:43:52 -0800
From:	Shaohua Li <shli@...com>
To:	<linux-kernel@...r.kernel.org>
CC:	<axboe@...nel.dk>, <Kernel-team@...com>
Subject: [PATCH] blkcg: put module reference

get_gendisk(and get_disk) increases module reference, but put_disk
doesn't decrease the reference. The module reference really should be
decreased in put_disk(), but there are a lot of cases drivers do
alloc_disk/put_disk. Before the put_disk usages are cleaned up, this is
easiest fix.

Signed-off-by: Shaohua Li <shli@...com>
---
 block/blk-cgroup.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 5a37188..58744ad 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -804,6 +804,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 	if (!disk)
 		return -ENODEV;
 	if (part) {
+		module_put(disk->fops->owner);
 		put_disk(disk);
 		return -ENODEV;
 	}
@@ -820,6 +821,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 		ret = PTR_ERR(blkg);
 		rcu_read_unlock();
 		spin_unlock_irq(disk->queue->queue_lock);
+		module_put(disk->fops->owner);
 		put_disk(disk);
 		/*
 		 * If queue was bypassing, we should retry.  Do so after a
@@ -853,6 +855,7 @@ void blkg_conf_finish(struct blkg_conf_ctx *ctx)
 {
 	spin_unlock_irq(ctx->disk->queue->queue_lock);
 	rcu_read_unlock();
+	module_put(ctx->disk->fops->owner);
 	put_disk(ctx->disk);
 }
 EXPORT_SYMBOL_GPL(blkg_conf_finish);
-- 
2.4.6