mm: implement find_get_pages_range_tag()

Patch series "Ranged pagevec tagged lookup", v3.

In this series I provide a ranged variant of pagevec_lookup_tag() and
use it in places where it makes sense.  This series removes some common
code and it also has a potential for speeding up some operations
similarly as for pagevec_lookup_range() (but for now I can think of only
artificial cases where this happens).

This patch (of 16):

Implement a variant of find_get_pages_tag() that stops iterating at
given index.  Lots of users of this function (through pagevec_lookup())
actually want a range lookup and all of them are currently open-coding
this.

Also create corresponding pagevec_lookup_range_tag() function.

Link: http://lkml.kernel.org/r/20171009151359.31984-2-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Steve French <sfrench@samba.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index e08b5339023c..956d6a80e126 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -366,8 +366,16 @@ static inline unsigned find_get_pages(struct address_space *mapping,
 }
 unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
                                unsigned int nr_pages, struct page **pages);
-unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
-                        int tag, unsigned int nr_pages, struct page **pages);
+unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
+                        pgoff_t end, int tag, unsigned int nr_pages,
+                        struct page **pages);
+static inline unsigned find_get_pages_tag(struct address_space *mapping,
+                        pgoff_t *index, int tag, unsigned int nr_pages,
+                        struct page **pages)
+{
+        return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag,
+                                        nr_pages, pages);
+}
 unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
                         int tag, unsigned int nr_entries,
                         struct page **entries, pgoff_t *indices);