From: Christoph Hellwig <hch@lst.de>
Date: Mon, 7 Jun 2021 01:49:50 +0000 (+1000)
Subject: xfs: remove ->b_offset handling for page backed buffers
X-Git-Tag: v5.14-rc1~97^2~36^2~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=54cd3aa6f8102f4648190fc93eb5dd8603de9b52;p=thirdparty%2Flinux.git

xfs: remove ->b_offset handling for page backed buffers

->b_offset can only be non-zero for _XBF_KMEM backed buffers, so
remove all code dealing with it for page backed buffers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[dgc: modified to fit this patchset]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index d02edb683cfd9..f901a74d61764 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -79,7 +79,7 @@ static inline int
 xfs_buf_vmap_len(
 	struct xfs_buf	*bp)
 {
-	return (bp->b_page_count * PAGE_SIZE) - bp->b_offset;
+	return (bp->b_page_count * PAGE_SIZE);
 }
 
 /*
@@ -281,7 +281,7 @@ xfs_buf_free_pages(
 	ASSERT(bp->b_flags & _XBF_PAGES);
 
 	if (xfs_buf_is_vmapped(bp))
-		vm_unmap_ram(bp->b_addr - bp->b_offset, bp->b_page_count);
+		vm_unmap_ram(bp->b_addr, bp->b_page_count);
 
 	for (i = 0; i < bp->b_page_count; i++) {
 		if (bp->b_pages[i])
@@ -442,7 +442,7 @@ _xfs_buf_map_pages(
 	ASSERT(bp->b_flags & _XBF_PAGES);
 	if (bp->b_page_count == 1) {
 		/* A single page buffer is always mappable */
-		bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
+		bp->b_addr = page_address(bp->b_pages[0]);
 	} else if (flags & XBF_UNMAPPED) {
 		bp->b_addr = NULL;
 	} else {
@@ -469,7 +469,6 @@ _xfs_buf_map_pages(
 
 		if (!bp->b_addr)
 			return -ENOMEM;
-		bp->b_addr += bp->b_offset;
 	}
 
 	return 0;
@@ -1680,7 +1679,6 @@ xfs_buf_offset(
 	if (bp->b_addr)
 		return bp->b_addr + offset;
 
-	offset += bp->b_offset;
 	page = bp->b_pages[offset >> PAGE_SHIFT];
 	return page_address(page) + (offset & (PAGE_SIZE-1));
 }
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 459ca34f26f58..464dc548fa238 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -167,7 +167,8 @@ struct xfs_buf {
 	atomic_t		b_pin_count;	/* pin count */
 	atomic_t		b_io_remaining;	/* #outstanding I/O requests */
 	unsigned int		b_page_count;	/* size of page array */
-	unsigned int		b_offset;	/* page offset in first page */
+	unsigned int		b_offset;	/* page offset of b_addr,
+						   only for _XBF_KMEM buffers */
 	int			b_error;	/* error code on I/O */
 
 	/*