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authorJan Kara <jack@suse.cz>2017-11-15 17:34:33 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-15 18:21:03 -0800
commit72b045aecdd856b083521f2a963705b4c2e59680 (patch)
tree586bdb2ee2ed3322084e10355b02e4e9c8fd622a /mm/filemap.c
parent6b4c54e3787bc03e810062bd257a3b05fd9c72d6 (diff)
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>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c33
1 files changed, 24 insertions, 9 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 594d73fef8b4..cf74d0dacc6a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1754,9 +1754,10 @@ repeat:
EXPORT_SYMBOL(find_get_pages_contig);
/**
- * find_get_pages_tag - find and return pages that match @tag
+ * find_get_pages_range_tag - find and return pages in given range matching @tag
* @mapping: the address_space to search
* @index: the starting page index
+ * @end: The final page index (inclusive)
* @tag: the tag index
* @nr_pages: the maximum number of pages
* @pages: where the resulting pages are placed
@@ -1764,8 +1765,9 @@ EXPORT_SYMBOL(find_get_pages_contig);
* Like find_get_pages, except we only return pages which are tagged with
* @tag. We update @index to index the next page for the traversal.
*/
-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)
{
struct radix_tree_iter iter;
void **slot;
@@ -1778,6 +1780,9 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
radix_tree_for_each_tagged(slot, &mapping->page_tree,
&iter, *index, tag) {
struct page *head, *page;
+
+ if (iter.index > end)
+ break;
repeat:
page = radix_tree_deref_slot(slot);
if (unlikely(!page))
@@ -1819,18 +1824,28 @@ repeat:
}
pages[ret] = page;
- if (++ret == nr_pages)
- break;
+ if (++ret == nr_pages) {
+ *index = pages[ret - 1]->index + 1;
+ goto out;
+ }
}
+ /*
+ * We come here when we got at @end. We take care to not overflow the
+ * index @index as it confuses some of the callers. This breaks the
+ * iteration when there is page at index -1 but that is already broken
+ * anyway.
+ */
+ if (end == (pgoff_t)-1)
+ *index = (pgoff_t)-1;
+ else
+ *index = end + 1;
+out:
rcu_read_unlock();
- if (ret)
- *index = pages[ret - 1]->index + 1;
-
return ret;
}
-EXPORT_SYMBOL(find_get_pages_tag);
+EXPORT_SYMBOL(find_get_pages_range_tag);
/**
* find_get_entries_tag - find and return entries that match @tag