diff options
| author | Jens Axboe <axboe@suse.de> | 2006-04-27 08:46:01 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@nelson.home.kernel.dk> | 2006-04-27 08:59:48 +0200 |
| commit | ebf43500ef148a380bd132743c3fc530111ac620 (patch) | |
| tree | 01ddb60f5662cf92b96b0468bf9820518a611209 | |
| parent | eb645a24de82496434cc81171d7f350edb327399 (diff) | |
[PATCH] Add find_get_pages_contig(): contiguous variant of find_get_pages()
find_get_pages_contig() will break out if we hit a hole in the page cache.
From Andrew Morton, small modifications and documentation by me.
Signed-off-by: Jens Axboe <axboe@suse.de>
| -rw-r--r-- | include/linux/pagemap.h | 2 | ||||
| -rw-r--r-- | mm/filemap.c | 32 |
2 files changed, 34 insertions, 0 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 9539efd4f7e6..7a1af574dedf 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -78,6 +78,8 @@ extern struct page * find_or_create_page(struct address_space *mapping, unsigned long index, gfp_t gfp_mask); 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); diff --git a/mm/filemap.c b/mm/filemap.c index 3ef20739e725..fd57442186cb 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -697,6 +697,38 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start, return ret; } +/** + * find_get_pages_contig - gang contiguous pagecache lookup + * @mapping: The address_space to search + * @index: 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. + */ +unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, + unsigned int nr_pages, struct page **pages) +{ + unsigned int i; + unsigned int ret; + + read_lock_irq(&mapping->tree_lock); + ret = radix_tree_gang_lookup(&mapping->page_tree, + (void **)pages, index, nr_pages); + for (i = 0; i < ret; i++) { + if (pages[i]->mapping == NULL || pages[i]->index != index) + break; + + page_cache_get(pages[i]); + index++; + } + read_unlock_irq(&mapping->tree_lock); + return i; +} + /* * 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. |