From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Thu, 31 Oct 2019 10:53:41 +0000 (+0300)
Subject: iocost: don't nest spin_lock_irq in ioc_weight_write()
X-Git-Tag: v5.4-rc6~10^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=41591a51f00d2dc7bb9dc6e9bedf56c5cf6f2392;p=thirdparty%2Fkernel%2Flinux.git

iocost: don't nest spin_lock_irq in ioc_weight_write()

This code causes a static analysis warning:

    block/blk-iocost.c:2113 ioc_weight_write() error: double lock 'irq'

We disable IRQs in blkg_conf_prep() and re-enable them in
blkg_conf_finish().  IRQ disable/enable should not be nested because
that means the IRQs will be enabled at the first unlock instead of the
second one.

Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost")
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 2a3db80c1dce7..a7ed434eae038 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2110,10 +2110,10 @@ static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf,
 			goto einval;
 	}
 
-	spin_lock_irq(&iocg->ioc->lock);
+	spin_lock(&iocg->ioc->lock);
 	iocg->cfg_weight = v;
 	weight_updated(iocg);
-	spin_unlock_irq(&iocg->ioc->lock);
+	spin_unlock(&iocg->ioc->lock);
 
 	blkg_conf_finish(&ctx);
 	return nbytes;