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bdi: remove bdi->wb_lock locking around bdi->dev clearing in bdi_unregister() 

The only places where NULL test on bdi->dev is used are
bdi_[un]register().  The functions can't be called in parallel anyway
and there's no point in protecting bdi->dev clearing with a lock.
Remove bdi->wb_lock grabbing around bdi->dev clearing and move it
after device_unregister() call so that bdi->dev doesn't have to be
cached in a local variable.

This patch shouldn't introduce any behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo 2014-09-08 08:03:58 +09:00 committed by Jens Axboe
parent e36f1dfce0
commit b68757341d
1 changed files with 2 additions and 8 deletions
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10
mm/backing-dev.c
View File

@ -402,21 +402,15 @@ static void bdi_prune_sb(struct backing_dev_info *bdi)
void bdi_unregister(struct backing_dev_info *bdi)
{
struct device *dev = bdi->dev;
if (dev) {
if (bdi->dev) {
bdi_set_min_ratio(bdi, 0);
trace_writeback_bdi_unregister(bdi);
bdi_prune_sb(bdi);
bdi_wb_shutdown(bdi);
bdi_debug_unregister(bdi);
spin_lock_bh(&bdi->wb_lock);
device_unregister(bdi->dev);
bdi->dev = NULL;
spin_unlock_bh(&bdi->wb_lock);
device_unregister(dev);
}
}
EXPORT_SYMBOL(bdi_unregister);