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[4/8] btrfs: don't access the bio directly in btrfs_csum_one_bio

Message ID 1480061273-5722-5-git-send-email-hch@lst.de (mailing list archive)
State Accepted
Headers show

Commit Message

Christoph Hellwig Nov. 25, 2016, 8:07 a.m. UTC 
Use bio_for_each_segment_all to iterate over the segments instead.
This requires a bit of reshuffling so that we only lookup up the ordered
item once inside the bio_for_each_segment_all loop.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/file-item.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)
diff mbox

Patch

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index d0d571c..fa8aa53 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -447,13 +447,12 @@  int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
 		       struct bio *bio, u64 file_start, int contig)
 {
 	struct btrfs_ordered_sum *sums;
-	struct btrfs_ordered_extent *ordered;
+	struct btrfs_ordered_extent *ordered = NULL;
 	char *data;
-	struct bio_vec *bvec = bio->bi_io_vec;
-	int bio_index = 0;
+	struct bio_vec *bvec;
 	int index;
 	int nr_sectors;
-	int i;
+	int i, j;
 	unsigned long total_bytes = 0;
 	unsigned long this_sum_bytes = 0;
 	u64 offset;
@@ -470,17 +469,20 @@  int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
 	if (contig)
 		offset = file_start;
 	else
-		offset = page_offset(bvec->bv_page) + bvec->bv_offset;
+		offset = 0; /* shut up gcc */
 
-	ordered = btrfs_lookup_ordered_extent(inode, offset);
-	BUG_ON(!ordered); /* Logic error */
 	sums->bytenr = (u64)bio->bi_iter.bi_sector << 9;
 	index = 0;
 
-	while (bio_index < bio->bi_vcnt) {
+	bio_for_each_segment_all(bvec, bio, j) {
 		if (!contig)
 			offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 
+		if (!ordered) {
+			ordered = btrfs_lookup_ordered_extent(inode, offset);
+			BUG_ON(!ordered); /* Logic error */
+		}
+
 		data = kmap_atomic(bvec->bv_page);
 
 		nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
@@ -529,9 +531,6 @@  int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
 		}
 
 		kunmap_atomic(data);
-
-		bio_index++;
-		bvec++;
 	}
 	this_sum_bytes = 0;
 	btrfs_add_ordered_sum(inode, ordered, sums);