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 <[email protected]> --- mm/backing-dev.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 1706cbb..4afeefe 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -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); -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
