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authorMatthew Wilcox <matthew.r.wilcox@intel.com>2014-06-04 16:07:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-04 16:54:02 -0700
commit47a191fd38ebddb1bd1510ec2bc1085c578c8868 (patch)
tree5c65289e7195f4ecd445b2b55e8d44cfa7e7ea00 /fs/mpage.c
parent57d998456ae8680ed446aa1993f45f4d8a9a5973 (diff)
downloadlwn-47a191fd38ebddb1bd1510ec2bc1085c578c8868.tar.gz
lwn-47a191fd38ebddb1bd1510ec2bc1085c578c8868.zip
fs/block_dev.c: add bdev_read_page() and bdev_write_page()
A block device driver may choose to provide a rw_page operation. These will be called when the filesystem is attempting to do page sized I/O to page cache pages (ie not for direct I/O). This does preclude I/Os that are larger than page size, so this may only be a performance gain for some devices. Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Tested-by: Dheeraj Reddy <dheeraj.reddy@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/mpage.c')
-rw-r--r--fs/mpage.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/mpage.c b/fs/mpage.c
index 10da0da73017..5f9ed622274f 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -269,6 +269,11 @@ do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
alloc_new:
if (bio == NULL) {
+ if (first_hole == blocks_per_page) {
+ if (!bdev_read_page(bdev, blocks[0] << (blkbits - 9),
+ page))
+ goto out;
+ }
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
min_t(int, nr_pages, bio_get_nr_vecs(bdev)),
GFP_KERNEL);
@@ -587,6 +592,13 @@ page_is_mapped:
alloc_new:
if (bio == NULL) {
+ if (first_unmapped == blocks_per_page) {
+ if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9),
+ page, wbc)) {
+ clean_buffers(page, first_unmapped);
+ goto out;
+ }
+ }
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
bio_get_nr_vecs(bdev), GFP_NOFS|__GFP_HIGH);
if (bio == NULL)