btrfs: remove unnecessary local variables for checksum size

Remove local variable that is then used just once and replace it with
fs_info::csum_size.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/compression.c

@@ -131,9 +131,8 @@ static int btrfs_decompress_bio(struct compressed_bio *cb);
 static inline int compressed_bio_size(struct btrfs_fs_info *fs_info,
 				      unsigned long disk_size)
 {
-	const u32 csum_size = fs_info->csum_size;
 	return sizeof(struct compressed_bio) +
-		(DIV_ROUND_UP(disk_size, fs_info->sectorsize)) * csum_size;
+		(DIV_ROUND_UP(disk_size, fs_info->sectorsize)) * fs_info->csum_size;
 }
 
 static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio,
@@ -627,7 +626,6 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 	struct extent_map *em;
 	blk_status_t ret = BLK_STS_RESOURCE;
 	int faili = 0;
-	const u32 csum_size = fs_info->csum_size;
 	u8 *sums;
 
 	em_tree = &BTRFS_I(inode)->extent_tree;
@@ -727,7 +725,7 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 
 			nr_sectors = DIV_ROUND_UP(comp_bio->bi_iter.bi_size,
 						  fs_info->sectorsize);
-			sums += csum_size * nr_sectors;
+			sums += fs_info->csum_size * nr_sectors;
 
 			ret = btrfs_map_bio(fs_info, comp_bio, mirror_num);
 			if (ret) {

fs/btrfs/disk-io.c

@@ -454,7 +454,6 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
 	u64 start = page_offset(page);
 	u64 found_start;
 	u8 result[BTRFS_CSUM_SIZE];
-	const u32 csum_size = fs_info->csum_size;
 	struct extent_buffer *eb;
 	int ret;
 
@@ -491,7 +490,7 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
 		WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
 		return ret;
 	}
-	write_extent_buffer(eb, result, 0, csum_size);
+	write_extent_buffer(eb, result, 0, fs_info->csum_size);
 
 	return 0;
 }

fs/btrfs/file-item.c

@@ -540,7 +540,6 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
 	int i;
 	u64 offset;
 	unsigned nofs_flag;
-	const u32 csum_size = fs_info->csum_size;
 
 	nofs_flag = memalloc_nofs_save();
 	sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
@@ -608,7 +607,7 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
 					    fs_info->sectorsize,
 					    sums->sums + index);
 			kunmap_atomic(data);
-			index += csum_size;
+			index += fs_info->csum_size;
 			offset += fs_info->sectorsize;
 			this_sum_bytes += fs_info->sectorsize;
 			total_bytes += fs_info->sectorsize;

fs/btrfs/ordered-data.h

@@ -137,9 +137,8 @@ static inline int btrfs_ordered_sum_size(struct btrfs_fs_info *fs_info,
 					 unsigned long bytes)
 {
 	int num_sectors = (int)DIV_ROUND_UP(bytes, fs_info->sectorsize);
-	const u32 csum_size = fs_info->csum_size;
 
-	return sizeof(struct btrfs_ordered_sum) + num_sectors * csum_size;
+	return sizeof(struct btrfs_ordered_sum) + num_sectors * fs_info->csum_size;
 }
 
 static inline void