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, 5 insertions, 4 deletions

diff --git a/mm/swap.c b/mm/swap.c
index a77d68f..e1c74eb 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -986,14 +986,15 @@ unsigned pagevec_lookup_range(struct pagevec *pvec,
 }
 EXPORT_SYMBOL(pagevec_lookup_range);
 
-unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
-		pgoff_t *index, int tag, unsigned nr_pages)
+unsigned pagevec_lookup_range_tag(struct pagevec *pvec,
+		struct address_space *mapping, pgoff_t *index, pgoff_t end,
+		int tag, unsigned nr_pages)
 {
-	pvec->nr = find_get_pages_tag(mapping, index, tag,
+	pvec->nr = find_get_pages_range_tag(mapping, index, end, tag,
 					nr_pages, pvec->pages);
 	return pagevec_count(pvec);
 }
-EXPORT_SYMBOL(pagevec_lookup_tag);
+EXPORT_SYMBOL(pagevec_lookup_range_tag);
 
 /*
  * Perform any setup for the swap system