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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>,
	William Kucharski <william.kucharski@oracle.com>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Chris Wilson <chris@chris-wilson.co.uk>,
	Matthew Auld <matthew.auld@intel.com>,
	Huang Ying <ying.huang@intel.com>,
	intel-gfx@lists.freedesktop.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 6/8] mm: Convert find_get_entry to return the head page
Date: Thu, 10 Sep 2020 19:33:16 +0100
Message-ID: <20200910183318.20139-7-willy@infradead.org> (raw)
In-Reply-To: <20200910183318.20139-1-willy@infradead.org>

There are only four callers remaining of find_get_entry().
get_shadow_from_swap_cache() only wants to see shadow entries and doesn't
care about which page is returned.  Push the find_subpage() call into
find_lock_entry(), find_get_incore_page() and pagecache_get_page().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/filemap.c    | 13 +++++++------
 mm/swap_state.c |  2 +-
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index d64f6f76bc0b..2f134383b0ae 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1567,19 +1567,19 @@ EXPORT_SYMBOL(page_cache_prev_miss);
 /**
  * find_get_entry - find and get a page cache entry
  * @mapping: the address_space to search
- * @offset: the page cache index
+ * @index: The page cache index.
  *
  * Looks up the page cache slot at @mapping & @offset.  If there is a
- * page cache page, it is returned with an increased refcount.
+ * page cache page, the head page is returned with an increased refcount.
  *
  * If the slot holds a shadow entry of a previously evicted page, or a
  * swap entry from shmem/tmpfs, it is returned.
  *
- * Return: the found page or shadow entry, %NULL if nothing is found.
+ * Return: The head page or shadow entry, %NULL if nothing is found.
  */
-struct page *find_get_entry(struct address_space *mapping, pgoff_t offset)
+struct page *find_get_entry(struct address_space *mapping, pgoff_t index)
 {
-	XA_STATE(xas, &mapping->i_pages, offset);
+	XA_STATE(xas, &mapping->i_pages, index);
 	struct page *page;
 
 	rcu_read_lock();
@@ -1607,7 +1607,6 @@ struct page *find_get_entry(struct address_space *mapping, pgoff_t offset)
 		put_page(page);
 		goto repeat;
 	}
-	page = find_subpage(page, offset);
 out:
 	rcu_read_unlock();
 
@@ -1644,6 +1643,7 @@ struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset)
 			put_page(page);
 			goto repeat;
 		}
+		page = find_subpage(page, offset);
 		VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page);
 	}
 	return page;
@@ -1690,6 +1690,7 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
 		page = NULL;
 	if (!page)
 		goto no_page;
+	page = find_subpage(page, index);
 
 	if (fgp_flags & FGP_LOCK) {
 		if (fgp_flags & FGP_NOWAIT) {
diff --git a/mm/swap_state.c b/mm/swap_state.c
index c79e2242dd04..c8cf1757ca06 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -432,7 +432,7 @@ struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
 	struct page *page = find_get_entry(mapping, index);
 
 	if (!xa_is_value(page))
-		return page;
+		return find_subpage(page, index);
 	if (!shmem_mapping(mapping))
 		return NULL;
 
-- 
2.28.0



  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-10 18:33 [PATCH v2 0/8] Return head pages from find_*_entry Matthew Wilcox (Oracle)
2020-09-10 18:33 ` [PATCH v2 1/8] mm: Factor find_get_incore_page out of mincore_page Matthew Wilcox (Oracle)
2020-09-10 18:33 ` [PATCH v2 2/8] mm: Use find_get_incore_page in memcontrol Matthew Wilcox (Oracle)
2020-09-10 18:33 ` [PATCH v2 3/8] mm: Optimise madvise WILLNEED Matthew Wilcox (Oracle)
2020-09-14 16:17   ` Qian Cai
2020-09-14 16:47     ` Qian Cai
2020-09-14 16:50     ` Matthew Wilcox
2020-09-14 19:44       ` Qian Cai
2020-09-10 18:33 ` [PATCH v2 4/8] proc: Optimise smaps for shmem entries Matthew Wilcox (Oracle)
2020-09-10 18:33 ` [PATCH v2 5/8] i915: Use find_lock_page instead of find_lock_entry Matthew Wilcox (Oracle)
2020-09-10 18:33 ` Matthew Wilcox (Oracle) [this message]
2020-09-14  8:55   ` [mm] 2037ab69a5: BUG:KASAN:null-ptr-deref_in_t kernel test robot
2020-09-14 11:27     ` Matthew Wilcox
2020-09-10 18:33 ` [PATCH v2 7/8] mm/shmem: Return head page from find_lock_entry Matthew Wilcox (Oracle)
2020-09-12  3:20   ` Matthew Wilcox
2020-09-10 18:33 ` [PATCH v2 8/8] mm: Add find_lock_head Matthew Wilcox (Oracle)
2020-09-15  8:10 ` [PATCH v2 0/8] Return head pages from find_*_entry Hugh Dickins
2020-09-15 12:53   ` Naresh Kamboju
2020-09-15 13:08     ` Matthew Wilcox

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