linux-kernel - [PATCH v2 09/12] mm: Pass pvec directly to find_get

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Date:   Mon, 14 Sep 2020 14:00:39 +0100
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     linux-mm@...ck.org
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Hugh Dickins <hughd@...gle.com>,
        William Kucharski <william.kucharski@...cle.com>,
        Johannes Weiner <hannes@...xchg.org>, Jan Kara <jack@...e.cz>,
        Yang Shi <yang.shi@...ux.alibaba.com>,
        Dave Chinner <dchinner@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 09/12] mm: Pass pvec directly to find_get_entries

All callers of find_get_entries() use a pvec, so pass it directly
instead of manipulating it in the caller.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 include/linux/pagemap.h |  3 +--
 mm/filemap.c            | 21 +++++++++------------
 mm/shmem.c              |  5 ++---
 mm/swap.c               |  4 +---
 4 files changed, 13 insertions(+), 20 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index d440c6750757..788c280737e0 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -414,8 +414,7 @@ static inline struct page *find_subpage(struct page *head, pgoff_t index)
 }
 
 unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
-		pgoff_t end, unsigned int nr_entries, struct page **entries,
-		pgoff_t *indices);
+		pgoff_t end, struct pagevec *pvec, pgoff_t *indices);
 unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
 			pgoff_t end, unsigned int nr_pages,
 			struct page **pages);
diff --git a/mm/filemap.c b/mm/filemap.c
index 6dc0a9b8c0fa..a4ad294a34dc 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1800,14 +1800,12 @@ static inline struct page *xas_find_get_entry(struct xa_state *xas,
  * @mapping:	The address_space to search
  * @start:	The starting page cache index
  * @end:	The final page index (inclusive).
- * @nr_entries:	The maximum number of entries
- * @entries:	Where the resulting entries are placed
+ * @pvec:	Where the resulting entries are placed.
  * @indices:	The cache indices corresponding to the entries in @entries
  *
- * find_get_entries() will search for and return a group of up to
- * @nr_entries entries in the mapping.  The entries are placed at
- * @entries.  find_get_entries() takes a reference against any actual
- * pages it returns.
+ * find_get_entries() will search for and return a batch of entries in
+ * the mapping.  The entries are placed in @pvec.  find_get_entries()
+ * takes a reference on any actual pages it returns.
  *
  * The search returns a group of mapping-contiguous page cache entries
  * with ascending indexes.  There may be holes in the indices due to
@@ -1824,15 +1822,12 @@ static inline struct page *xas_find_get_entry(struct xa_state *xas,
  * Return: the number of pages and shadow entries which were found.
  */
 unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
-		pgoff_t end, unsigned int nr_entries, struct page **entries,
-		pgoff_t *indices)
+		pgoff_t end, struct pagevec *pvec, pgoff_t *indices)
 {
 	XA_STATE(xas, &mapping->i_pages, start);
 	struct page *page;
 	unsigned int ret = 0;
-
-	if (!nr_entries)
-		return 0;
+	unsigned nr_entries = PAGEVEC_SIZE;
 
 	rcu_read_lock();
 	while ((page = xas_find_get_entry(&xas, end, XA_PRESENT))) {
@@ -1847,11 +1842,13 @@ unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
 		}
 
 		indices[ret] = xas.xa_index;
-		entries[ret] = page;
+		pvec->pages[ret] = page;
 		if (++ret == nr_entries)
 			break;
 	}
 	rcu_read_unlock();
+
+	pvec->nr = ret;
 	return ret;
 }
 
diff --git a/mm/shmem.c b/mm/shmem.c
index 404e45c285ca..b2b94025841a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -963,9 +963,8 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 	while (index < end) {
 		cond_resched();
 
-		pvec.nr = find_get_entries(mapping, index, end - 1,
-				PAGEVEC_SIZE, pvec.pages, indices);
-		if (!pvec.nr) {
+		if (!find_get_entries(mapping, index, end - 1, &pvec,
+				indices)) {
 			/* If all gone or hole-punch or unfalloc, we're done */
 			if (index == start || end != -1)
 				break;
diff --git a/mm/swap.c b/mm/swap.c
index d4e3ba4c967c..40b23300d353 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -1060,9 +1060,7 @@ unsigned pagevec_lookup_entries(struct pagevec *pvec,
 		struct address_space *mapping, pgoff_t start, pgoff_t end,
 		pgoff_t *indices)
 {
-	pvec->nr = find_get_entries(mapping, start, end, PAGEVEC_SIZE,
-				    pvec->pages, indices);
-	return pagevec_count(pvec);
+	return find_get_entries(mapping, start, end, pvec, indices);
 }
 
 /**
-- 
2.28.0