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.
Reviewed-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
include/linux/pagemap.h | 12 ++++++++++--
include/linux/pagevec.h | 11 +++++++++--
mm/filemap.c | 33 ++++++++++++++++++++++++---------
mm/swap.c | 9 +++++----
4 files changed, 48 insertions(+), 17 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 5bbd6780f205..75cd074a23b4 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -365,8 +365,16 @@ 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);
diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
index 4dcd5506f1ed..371edacc10d5 100644
--- a/include/linux/pagevec.h
+++ b/include/linux/pagevec.h
@@ -37,9 +37,16 @@ static inline unsigned pagevec_lookup(struct pagevec *pvec,
return pagevec_lookup_range(pvec, mapping, start, (pgoff_t)-1);
}
-unsigned pagevec_lookup_tag(struct pagevec *pvec,
+unsigned pagevec_lookup_range_tag(struct pagevec *pvec,
+ struct address_space *mapping, pgoff_t *index, pgoff_t end,
+ int tag, unsigned nr_pages);
+static inline unsigned pagevec_lookup_tag(struct pagevec *pvec,
struct address_space *mapping, pgoff_t *index, int tag,
- unsigned nr_pages);
+ unsigned nr_pages)
+{
+ return pagevec_lookup_range_tag(pvec, mapping, index, (pgoff_t)-1, tag,
+ nr_pages);
+}
static inline void pagevec_init(struct pagevec *pvec, int cold)
{
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 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
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 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
}
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
diff --git a/mm/swap.c b/mm/swap.c
index a77d68f2c1b6..e1c74eb8a775 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
--
2.12.3
