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-rw-r--r--include/linux/pagemap.h137
1 files changed, 125 insertions, 12 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 3659c8923d8e..2d144289eafc 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -355,18 +355,131 @@ unsigned __find_get_pages(struct address_space *mapping,
pgoff_t start, pgoff_t end,
unsigned nr_entries, struct page **entries,
pgoff_t *indices, unsigned flags);
-unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
- unsigned int nr_entries, struct page **entries,
- pgoff_t *indices);
-unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
- unsigned int nr_pages, struct page **pages);
-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_entries_tag(struct address_space *mapping, pgoff_t start,
- int tag, unsigned int nr_entries,
- struct page **entries, pgoff_t *indices);
+
+/**
+ * find_get_entries - gang pagecache lookup
+ * @mapping: The address_space to search
+ * @start: The starting page cache index
+ * @nr_entries: The maximum number of entries
+ * @entries: Where the resulting entries are placed
+ * @indices: The cache indices corresponding to the entries in @entries
+ *
+ * find_get_entries() will search for and return a group of up to
+ * @nr_entries entries in the mapping. The entries are placed at
+ * @entries. find_get_entries() takes a reference against any actual
+ * pages it returns.
+ *
+ * The search returns a group of mapping-contiguous page cache entries
+ * with ascending indexes. There may be holes in the indices due to
+ * not-present pages.
+ *
+ * Any shadow entries of evicted pages, or swap entries from
+ * shmem/tmpfs, are included in the returned array.
+ *
+ * find_get_entries() returns the number of pages and shadow entries
+ * which were found.
+ */
+static inline unsigned find_get_entries(struct address_space *mapping,
+ pgoff_t start, unsigned nr_entries,
+ struct page **entries, pgoff_t *indices)
+{
+ return __find_get_pages(mapping, start, ULONG_MAX,
+ nr_entries, entries, indices,
+ RADIX_TREE_ITER_EXCEPTIONAL);
+}
+
+/**
+ * find_get_pages - gang pagecache lookup
+ * @mapping: The address_space to search
+ * @start: The starting page index
+ * @nr_pages: The maximum number of pages
+ * @pages: Where the resulting pages are placed
+ *
+ * find_get_pages() will search for and return a group of up to
+ * @nr_pages pages in the mapping. The pages are placed at @pages.
+ * find_get_pages() takes a reference against the returned pages.
+ *
+ * The search returns a group of mapping-contiguous pages with ascending
+ * indexes. There may be holes in the indices due to not-present pages.
+ *
+ * find_get_pages() returns the number of pages which were found.
+ */
+static inline unsigned find_get_pages(struct address_space *mapping,
+ pgoff_t start, unsigned nr_pages,
+ struct page **pages)
+{
+ return __find_get_pages(mapping, start, ULONG_MAX,
+ nr_pages, pages, NULL, 0);
+}
+
+/**
+ * find_get_pages_contig - gang contiguous pagecache lookup
+ * @mapping: The address_space to search
+ * @start: The starting page index
+ * @nr_pages: The maximum number of pages
+ * @pages: Where the resulting pages are placed
+ *
+ * find_get_pages_contig() works exactly like find_get_pages(), except
+ * that the returned number of pages are guaranteed to be contiguous.
+ *
+ * find_get_pages_contig() returns the number of pages which were found.
+ */
+static inline unsigned find_get_pages_contig(struct address_space *mapping,
+ pgoff_t start, unsigned nr_pages,
+ struct page **pages)
+{
+ return __find_get_pages(mapping, start, ULONG_MAX,
+ nr_pages, pages, NULL,
+ RADIX_TREE_ITER_CONTIG);
+}
+
+/**
+ * find_get_pages_tag - find and return pages that match @tag
+ * @mapping: the address_space to search
+ * @index: the starting page index
+ * @tag: the tag index
+ * @nr_pages: the maximum number of pages
+ * @pages: where the resulting pages are placed
+ *
+ * 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.
+ */
+static inline unsigned find_get_pages_tag(struct address_space *mapping,
+ pgoff_t *index, int tag,
+ unsigned nr_pages, struct page **pages)
+{
+ unsigned ret;
+
+ ret = __find_get_pages(mapping, *index, ULONG_MAX,
+ nr_pages, pages, NULL,
+ RADIX_TREE_ITER_TAGGED|tag);
+ if (ret)
+ *index = pages[ret - 1]->index + 1;
+
+ return ret;
+}
+
+/**
+ * find_get_entries_tag - find and return entries that match @tag
+ * @mapping: the address_space to search
+ * @start: the starting page cache index
+ * @tag: the tag index
+ * @nr_entries: the maximum number of entries
+ * @entries: where the resulting entries are placed
+ * @indices: the cache indices corresponding to the entries in @entries
+ *
+ * Like find_get_entries, except we only return entries which are tagged with
+ * @tag.
+ */
+static inline unsigned find_get_entries_tag(struct address_space *mapping,
+ pgoff_t start, int tag, unsigned nr_entries,
+ struct page **entries, pgoff_t *indices)
+{
+ return __find_get_pages(mapping, start, ULONG_MAX,
+ nr_entries, entries, indices,
+ RADIX_TREE_ITER_EXCEPTIONAL|
+ RADIX_TREE_ITER_TAGGED|tag);
+}
struct page *grab_cache_page_write_begin(struct address_space *mapping,
pgoff_t index, unsigned flags);