Re: [PATCH 2/4] filemap: kill page_cache_read usage in filemap_fault

[Johannes Weiner]

On Fri, Nov 30, 2018 at 02:58:10PM -0500, Josef Bacik wrote:
> If we do not have a page at filemap_fault time we'll do this weird
> forced page_cache_read thing to populate the page, and then drop it
> again and loop around and find it.  This makes for 2 ways we can read a
> page in filemap_fault, and it's not really needed.  Instead add a
> FGP_FOR_MMAP flag so that pagecache_get_page() will return a unlocked
> page that's in pagecache.  Then use the normal page locking and readpage
> logic already in filemap_fault.  This simplifies the no page in page
> cache case significantly.
> 
> Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>

That's a great simplification. Looks correct to me.

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>