Re: [PATCH 07/10] xfs: simplify the b_page_count calculation
From: "Darrick J. Wong" <djwong@kernel.org>
Date: 2021-05-27 23:15:46
On Thu, May 27, 2021 at 08:47:19AM +1000, Dave Chinner wrote:
From: Christoph Hellwig <hch@lst.de> Ever since we stopped using the Linux page cache
The premise of /that/ is unsettling. Um... did b_pages[] point to pagecache pages, and that's why all that offset shifting was necessary?
to back XFS buffes
s/buffes/buffers/
there is no need to take the start sector into account for calculating the number of pages in a buffer, as the data always start from the beginning of the buffer.
Reviewed-by: Darrick J. Wong <djwong@kernel.org> --D
quoted hunk ↗ jump to hunk
Signed-off-by: Christoph Hellwig <hch@lst.de> [dgc: modified to suit this series] Signed-off-by: Dave Chinner <redacted> --- fs/xfs/xfs_buf.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-)diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 87151d78a0d8..1500a9c63432 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c@@ -348,14 +348,13 @@ xfs_buf_alloc_kmem( static int xfs_buf_alloc_pages( struct xfs_buf *bp, - uint page_count, xfs_buf_flags_t flags) { gfp_t gfp_mask = xb_to_gfp(flags); long filled = 0; /* Make sure that we have a page list */ - bp->b_page_count = page_count; + bp->b_page_count = DIV_ROUND_UP(BBTOB(bp->b_length), PAGE_SIZE); if (bp->b_page_count <= XB_PAGES) { bp->b_pages = bp->b_page_array; } else {@@ -409,7 +408,6 @@ xfs_buf_allocate_memory( uint flags) { size_t size; - xfs_off_t start, end; int error; /*@@ -424,11 +422,7 @@ xfs_buf_allocate_memory( if (!error) return 0; } - - start = BBTOB(bp->b_maps[0].bm_bn) >> PAGE_SHIFT; - end = (BBTOB(bp->b_maps[0].bm_bn + bp->b_length) + PAGE_SIZE - 1) - >> PAGE_SHIFT; - return xfs_buf_alloc_pages(bp, end - start, flags); + return xfs_buf_alloc_pages(bp, flags); } /*@@ -922,7 +916,6 @@ xfs_buf_get_uncached( int flags, struct xfs_buf **bpp) { - unsigned long page_count; int error; struct xfs_buf *bp; DEFINE_SINGLE_BUF_MAP(map, XFS_BUF_DADDR_NULL, numblks);@@ -934,8 +927,7 @@ xfs_buf_get_uncached( if (error) return error; - page_count = PAGE_ALIGN(numblks << BBSHIFT) >> PAGE_SHIFT; - error = xfs_buf_alloc_pages(bp, page_count, flags); + error = xfs_buf_alloc_pages(bp, flags); if (error) goto fail_free_buf;-- 2.31.1