No need to walk the page list if bp->b_addr is valid. That also means
b_offset doesn't need to be taken into account in the unmapped loop as
b_offset is only set for kmem backed buffers which are always mapped.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/xfs_buf.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 15bb790359f8..9e0c64511936 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1688,13 +1688,18 @@ xfs_buf_zero(
{
size_t bend;
+ if (bp->b_addr) {
+ memset(bp->b_addr + boff, 0, bsize);
+ return;
+ }
+
bend = boff + bsize;
while (boff < bend) {
struct page *page;
int page_index, page_offset, csize;
- page_index = (boff + bp->b_offset) >> PAGE_SHIFT;
- page_offset = (boff + bp->b_offset) & ~PAGE_MASK;
+ page_index = boff >> PAGE_SHIFT;
+ page_offset = boff & ~PAGE_MASK;
page = bp->b_pages[page_index];
csize = min_t(size_t, PAGE_SIZE - page_offset,
BBTOB(bp->b_length) - boff);
--
2.45.2
