Patch "btrfs: remove unnecessary parameter delalloc_start for writepage_delalloc()" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    btrfs: remove unnecessary parameter delalloc_start for writepage_delalloc()

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     btrfs-remove-unnecessary-parameter-delalloc_start-fo.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 94387fc302212882a1e1528e9416e80d2ed23b89
Author: Qu Wenruo <wqu@xxxxxxxx>
Date:   Mon Sep 27 15:21:44 2021 +0800

    btrfs: remove unnecessary parameter delalloc_start for writepage_delalloc()
    
    [ Upstream commit cf3075fb36c6a98ea890f4a50b4419ff2fff9a2f ]
    
    In function __extent_writepage() we always pass page start to
    @delalloc_start for writepage_delalloc().
    
    Thus we don't really need @delalloc_start parameter as we can extract it
    from @page.
    
    Remove @delalloc_start parameter and make __extent_writepage() to
    declare @page_start and @page_end as const.
    
    Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
    Signed-off-by: David Sterba <dsterba@xxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 41862045b3de3..a72a8d4d4a72e 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3780,10 +3780,11 @@ static void update_nr_written(struct writeback_control *wbc,
  */
 static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 		struct page *page, struct writeback_control *wbc,
-		u64 delalloc_start, unsigned long *nr_written)
+		unsigned long *nr_written)
 {
-	u64 page_end = delalloc_start + PAGE_SIZE - 1;
+	u64 page_end = page_offset(page) + PAGE_SIZE - 1;
 	bool found;
+	u64 delalloc_start = page_offset(page);
 	u64 delalloc_to_write = 0;
 	u64 delalloc_end = 0;
 	int ret;
@@ -4068,8 +4069,8 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 			      struct extent_page_data *epd)
 {
 	struct inode *inode = page->mapping->host;
-	u64 start = page_offset(page);
-	u64 page_end = start + PAGE_SIZE - 1;
+	const u64 page_start = page_offset(page);
+	const u64 page_end = page_start + PAGE_SIZE - 1;
 	int ret;
 	int nr = 0;
 	size_t pg_offset;
@@ -4104,8 +4105,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	}
 
 	if (!epd->extent_locked) {
-		ret = writepage_delalloc(BTRFS_I(inode), page, wbc, start,
-					 &nr_written);
+		ret = writepage_delalloc(BTRFS_I(inode), page, wbc, &nr_written);
 		if (ret == 1)
 			return 0;
 		if (ret)
@@ -4155,7 +4155,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	 * capable of that.
 	 */
 	if (PageError(page))
-		end_extent_writepage(page, ret, start, page_end);
+		end_extent_writepage(page, ret, page_start, page_end);
 	unlock_page(page);
 	ASSERT(ret <= 0);
 	return ret;