Re: [PATCH 18/20] dax: Make cache flushing protected by entry lock

[Jan Kara <jack@suse.cz>]

On Tue 18-10-16 13:20:13, Ross Zwisler wrote:
> On Tue, Sep 27, 2016 at 06:08:22PM +0200, Jan Kara wrote:
> > Currently, flushing of caches for DAX mappings was ignoring entry lock.
> > So far this was ok (modulo a bug that a difference in entry lock could
> > cause cache flushing to be mistakenly skipped) but in the following
> > patches we will write-protect PTEs on cache flushing and clear dirty
> > tags. For that we will need more exclusion. So do cache flushing under
> > an entry lock. This allows us to remove one lock-unlock pair of
> > mapping->tree_lock as a bonus.
> > 
> > Signed-off-by: Jan Kara <jack@suse.cz>
> 
> > @@ -716,15 +736,13 @@ static int dax_writeback_one(struct block_device *bdev,
> >  	}
> >  
> >  	wb_cache_pmem(dax.addr, dax.size);
> > -
> > -	spin_lock_irq(&mapping->tree_lock);
> > -	radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE);
> > -	spin_unlock_irq(&mapping->tree_lock);
> > - unmap:
> > +unmap:
> >  	dax_unmap_atomic(bdev, &dax);
> > +	put_locked_mapping_entry(mapping, index, entry);
> >  	return ret;
> >  
> > - unlock:
> > +put_unlock:
> 
> I know there's an ongoing debate about this, but can you please stick a space
> in front of the labels to make the patches pretty & to be consistent with the
> rest of the DAX code?

OK, done.

> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>

Thanks!

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR
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