Implement find_get_entries_range_tag() (actually convert
find_get_entries_tag() tag to it as the only user of
find_get_entries_tag() needs a ranged lookup) and use it in DAX which is
the only user of this interface. This is mostly for consistency with
other page/entry iteration interfaces.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/dax.c | 12 +++---------
include/linux/pagemap.h | 3 ++-
mm/filemap.c | 36 ++++++++++++++++++++++++++----------
3 files changed, 31 insertions(+), 20 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 4b295c544fd4..acf17b55f76b 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -819,7 +819,6 @@ int dax_writeback_mapping_range(struct address_space *mapping,
pgoff_t indices[PAGEVEC_SIZE];
struct dax_device *dax_dev;
struct pagevec pvec;
- bool done = false;
int i, ret = 0;
if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT))
@@ -840,20 +839,15 @@ int dax_writeback_mapping_range(struct address_space *mapping,
tag_pages_for_writeback(mapping, start_index, end_index);
pagevec_init(&pvec, 0);
- while (!done) {
- pvec.nr = find_get_entries_tag(mapping, &start_index,
- PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE,
+ while (start_index <= end_index) {
+ pvec.nr = find_get_entries_range_tag(mapping, &start_index,
+ end_index, PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE,
pvec.pages, indices);
if (pvec.nr == 0)
break;
for (i = 0; i < pvec.nr; i++) {
- if (indices[i] > end_index) {
- done = true;
- break;
- }
-
ret = dax_writeback_one(bdev, dax_dev, mapping,
indices[i], pvec.pages[i]);
if (ret < 0)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1dc7e54ec32a..38227e670a83 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -365,7 +365,8 @@ static inline unsigned find_get_pages_tag(struct address_space *mapping,
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,
+unsigned find_get_entries_range_tag(struct address_space *mapping,
+ pgoff_t *start, pgoff_t end,
int tag, unsigned int nr_entries,
struct page **entries, pgoff_t *indices);
diff --git a/mm/filemap.c b/mm/filemap.c
index 3eb05c91c07a..06f82ed9096e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1720,9 +1720,10 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
EXPORT_SYMBOL(find_get_pages_range_tag);
/**
- * find_get_entries_tag - find and return entries that match @tag
+ * find_get_entries_range_tag - find and return entries that match @tag
* @mapping: the address_space to search
* @start: the starting page cache index
+ * @end: the final page cache index (inclusive)
* @tag: the tag index
* @nr_entries: the maximum number of entries
* @entries: where the resulting entries are placed
@@ -1731,9 +1732,10 @@ EXPORT_SYMBOL(find_get_pages_range_tag);
* Like find_get_entries, except we only return entries which are tagged with
* @tag.
*/
-unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t *start,
- int tag, unsigned int nr_entries,
- struct page **entries, pgoff_t *indices)
+unsigned find_get_entries_range_tag(struct address_space *mapping,
+ pgoff_t *start, pgoff_t end, int tag,
+ unsigned int nr_entries, struct page **entries,
+ pgoff_t *indices)
{
void **slot;
unsigned int ret = 0;
@@ -1746,6 +1748,9 @@ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t *start,
radix_tree_for_each_tagged(slot, &mapping->page_tree,
&iter, *start, tag) {
struct page *head, *page;
+
+ if (iter.index > end)
+ break;
repeat:
page = radix_tree_deref_slot(slot);
if (unlikely(!page))
@@ -1782,17 +1787,28 @@ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t *start,
export:
indices[ret] = iter.index;
entries[ret] = page;
- if (++ret == nr_entries)
- break;
+ if (++ret == nr_entries) {
+ *start = indices[ret - 1] + 1;
+ goto out;
+ }
}
- rcu_read_unlock();
- if (ret)
- *start = indices[ret - 1] + 1;
+ /*
+ * 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)
+ *start = (pgoff_t)-1;
+ else
+ *start = end + 1;
+out:
+ rcu_read_unlock();
return ret;
}
-EXPORT_SYMBOL(find_get_entries_tag);
+EXPORT_SYMBOL(find_get_entries_range_tag);
/*
* CD/DVDs are error prone. When a medium error occurs, the driver may fail
--
2.12.3
