[RFC PATCH V3 06/10] iomap: use attach/detach_page_private

From: Guoqing Jiang
Date: Thu May 07 2020 - 17:44:52 EST


Since the new pair function is introduced, we can call them to clean the
code in iomap.

Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
Cc: linux-xfs@xxxxxxxxxxxxxxx
Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
---
RFC V2 -> RFC V3
1. rename clear_page_private to detach_page_private.

RFC -> RFC V2
1. change the name of new functions to attach/clear_page_private.
2. call attach_page_private(newpage, clear_page_private(page)) to
cleanup code further as suggested by Matthew Wilcox.
3. don't return attach_page_private in iomap_page_create per the
comment from Christoph Hellwig.

fs/iomap/buffered-io.c | 19 ++++---------------
1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 89e21961d1ad..e3031007b4ae 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -59,24 +59,19 @@ iomap_page_create(struct inode *inode, struct page *page)
* migrate_page_move_mapping() assumes that pages with private data have
* their count elevated by 1.
*/
- get_page(page);
- set_page_private(page, (unsigned long)iop);
- SetPagePrivate(page);
+ attach_page_private(page, iop);
return iop;
}

static void
iomap_page_release(struct page *page)
{
- struct iomap_page *iop = to_iomap_page(page);
+ struct iomap_page *iop = detach_page_private(page);

if (!iop)
return;
WARN_ON_ONCE(atomic_read(&iop->read_count));
WARN_ON_ONCE(atomic_read(&iop->write_count));
- ClearPagePrivate(page);
- set_page_private(page, 0);
- put_page(page);
kfree(iop);
}

@@ -554,14 +549,8 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage,
if (ret != MIGRATEPAGE_SUCCESS)
return ret;

- if (page_has_private(page)) {
- ClearPagePrivate(page);
- get_page(newpage);
- set_page_private(newpage, page_private(page));
- set_page_private(page, 0);
- put_page(page);
- SetPagePrivate(newpage);
- }
+ if (page_has_private(page))
+ attach_page_private(newpage, detach_page_private(page));

if (mode != MIGRATE_SYNC_NO_COPY)
migrate_page_copy(newpage, page);
--
2.17.1