From: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Thu, 31 Dec 2020 22:04:15 +0000 (+0000)
Subject: mm/swap: optimise get_shadow_from_swap_cache
X-Git-Tag: howlett/maple_spf/20210104~145
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=348484d1f320e45e32dea2c962aca1aa72a832a0;p=users%2Fjedix%2Flinux-maple.git

mm/swap: optimise get_shadow_from_swap_cache

There's no need to get a reference to the page, just load the entry and
see if it's a shadow entry.

Link: https://lkml.kernel.org/r/20201112212641.27837-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/swap_state.c b/mm/swap_state.c
index cbce6f28d32f..d3ccfab6c9b7 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -113,11 +113,9 @@ void *get_shadow_from_swap_cache(swp_entry_t entry)
 	pgoff_t idx = swp_offset(entry);
 	struct page *page;
 
-	page = find_get_entry(address_space, idx);
+	page = xa_load(&address_space->i_pages, idx);
 	if (xa_is_value(page))
 		return page;
-	if (page)
-		put_page(page);
 	return NULL;
 }