btrfs: remove duplicated parameters from submit_data_read_repair()

The function submit_data_read_repair() is only called for buffered data
read path, thus those members can be calculated using bvec directly:

- start
  start = page_offset(bvec->bv_page) + bvec->bv_offset;

- end
  end = start + bvec->bv_len - 1;

- page
  page = bvec->bv_page;

- pgoff
  pgoff = bvec->bv_offset;

Thus we can safely replace those 4 parameters with just one bio_vec.

Also remove the unused return value.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
[hch: also remove the return value]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -2727,18 +2727,17 @@ static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
 		btrfs_subpage_end_reader(fs_info, page, start, len);
 }
 
-static blk_status_t submit_data_read_repair(struct inode *inode,
-					    struct bio *failed_bio,
-					    u32 bio_offset, struct page *page,
-					    unsigned int pgoff,
-					    u64 start, u64 end,
-					    int failed_mirror,
-					    unsigned int error_bitmap)
+static void submit_data_read_repair(struct inode *inode, struct bio *failed_bio,
+				    u32 bio_offset, const struct bio_vec *bvec,
+				    int failed_mirror, unsigned int error_bitmap)
 {
+	const unsigned int pgoff = bvec->bv_offset;
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct page *page = bvec->bv_page;
+	const u64 start = page_offset(bvec->bv_page) + bvec->bv_offset;
+	const u64 end = start + bvec->bv_len - 1;
 	const u32 sectorsize = fs_info->sectorsize;
 	const int nr_bits = (end + 1 - start) >> fs_info->sectorsize_bits;
-	int error = 0;
 	int i;
 
 	BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
@@ -2785,11 +2784,9 @@ static blk_status_t submit_data_read_repair(struct inode *inode,
 			continue;
 		}
 		/*
-		 * Repair failed, just record the error but still continue.
-		 * Or the remaining sectors will not be properly unlocked.
+		 * Continue on failed repair, otherwise the remaining sectors
+		 * will not be properly unlocked.
 		 */
-		if (!error)
-			error = ret;
 next:
 		end_page_read(page, uptodate, start + offset, sectorsize);
 		if (uptodate)
@@ -2802,7 +2799,6 @@ next:
 				start + offset + sectorsize - 1,
 				&cached);
 	}
-	return errno_to_blk_status(error);
 }
 
 /* lots and lots of room for performance fixes in the end_bio funcs */
@@ -3095,10 +3091,8 @@ static void end_bio_extent_readpage(struct bio *bio)
 			 * submit_data_read_repair() will handle all the good
 			 * and bad sectors, we just continue to the next bvec.
 			 */
-			submit_data_read_repair(inode, bio, bio_offset, page,
-						start - page_offset(page),
-						start, end, mirror,
-						error_bitmap);
+			submit_data_read_repair(inode, bio, bio_offset, bvec,
+						mirror, error_bitmap);
 
 			ASSERT(bio_offset + len > bio_offset);
 			bio_offset += len;