On Thu, Apr 30, 2015 at 10:32:33AM +1000, NeilBrown wrote:
>
> bdi_unregister() now contains very little functionality.
>
> It contains a "WARN_ON" if bdi->dev is NULL. This warning is of no
> real consequence as bdi->dev isn't needed by anything else in the function,
> and it triggers if
> blk_cleanup_queue() -> bdi_destroy()
> is called before bdi_unregister, which a subsequent patch will make happen.
> So this isn't wanted.
>
> It also calls bdi_set_min_ratio(). This needs to be called after
> writes through the bdi have all been flushed, and before the bdi is destroyed.
> Calling it early is better than calling it late as it frees up a global
> resource.
>
> Calling it immediately after bdi_wb_shutdown() in bdi_destroy()
> perfectly fits these requirements.
>
> So bdi_unregister can be discarded with the important content moved to
> bdi_destroy, as can the
> writeback_bdi_unregister
> event which is already not used.
>
> This is tagged for 'stable' as it is a pre-requisite for a subsequent
> patch which moves calls to blk_cleanup_queue() before calls to
> del_gendisk(). The commit identified as 'Fixes' removed a lot of
> other functionality from bdi_unregister(), and made a change which
> necessitated moving the blk_cleanup_queue() calls.
>
> Reported-by: Mike Snitzer <snit...@redhat.com>
> Cc: Christoph Hellwig <h...@lst.de>
> Cc: Peter Zijlstra <pet...@infradead.org>
> Cc: sta...@vger.kernel.org (v4.0)
> Fixes: c4db59d31e39ea067c32163ac961e9c80198fd37
Fixes: c4db59d31e39 ("fs: don't reassign dirty inodes to
default_backing_dev_info")
> Signed-off-by: NeilBrown <ne...@suse.de>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
