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 2a3db80..a7ed434 100644 (file)
--- 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;