btrfs: use cached value of fs_info::csum_size everywhere

btrfs_get_16 shows up in the system performance profiles (helper to read
16bit values from on-disk structures). This is partially because of the
checksum size that's frequently read along with data reads/writes, other
u16 uses are from item size or directory entries.

Replace all calls to btrfs_super_csum_size by the cached value from
fs_info.

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

fs/btrfs/btrfs_inode.h

@@ -331,8 +331,7 @@ static inline void btrfs_print_data_csum_error(struct btrfs_inode *inode,
 		u64 logical_start, u8 *csum, u8 *csum_expected, int mirror_num)
 {
 	struct btrfs_root *root = inode->root;
-	struct btrfs_super_block *sb = root->fs_info->super_copy;
-	const u16 csum_size = btrfs_super_csum_size(sb);
+	const u16 csum_size = root->fs_info->csum_size;
 
 	/* Output minus objectid, which is more meaningful */
 	if (root->root_key.objectid >= BTRFS_LAST_FREE_OBJECTID)

fs/btrfs/check-integrity.c

@@ -660,7 +660,7 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 		return -1;
 	}
 
-	state->csum_size = btrfs_super_csum_size(selected_super);
+	state->csum_size = state->fs_info->csum_size;
 
 	for (pass = 0; pass < 3; pass++) {
 		int num_copies;

fs/btrfs/compression.c

@@ -131,7 +131,7 @@ 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)
 {
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 
 	return sizeof(struct compressed_bio) +
 		(DIV_ROUND_UP(disk_size, fs_info->sectorsize)) * csum_size;
@@ -142,7 +142,7 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio,
 {
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
-	const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 	struct page *page;
 	unsigned long i;
 	char *kaddr;
@@ -628,7 +628,7 @@ 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 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 	u8 *sums;
 
 	em_tree = &BTRFS_I(inode)->extent_tree;

fs/btrfs/disk-io.c

@@ -321,7 +321,7 @@ static int btrfs_check_super_csum(struct btrfs_fs_info *fs_info,
 	crypto_shash_digest(shash, raw_disk_sb + BTRFS_CSUM_SIZE,
 			    BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE, result);
 
-	if (memcmp(disk_sb->csum, result, btrfs_super_csum_size(disk_sb)))
+	if (memcmp(disk_sb->csum, result, fs_info->csum_size))
 		return 1;
 
 	return 0;
@@ -454,7 +454,7 @@ 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];
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 	struct extent_buffer *eb;
 	int ret;
 
@@ -543,7 +543,7 @@ int btrfs_validate_metadata_buffer(struct btrfs_io_bio *io_bio, u64 phy_offset,
 
 	eb = (struct extent_buffer *)page->private;
 	fs_info = eb->fs_info;
-	csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	csum_size = fs_info->csum_size;
 
 	/* the pending IO might have been the only thing that kept this buffer
 	 * in memory.  Make sure we have a ref for all this other checks

fs/btrfs/extent_io.c

@@ -2689,7 +2689,7 @@ blk_status_t btrfs_submit_read_repair(struct inode *inode,
 	repair_bio->bi_private = failed_bio->bi_private;
 
 	if (failed_io_bio->csum) {
-		const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+		const u16 csum_size = fs_info->csum_size;
 
 		repair_io_bio->csum = repair_io_bio->csum_inline;
 		memcpy(repair_io_bio->csum,

fs/btrfs/file-item.c

@@ -181,7 +181,7 @@ btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 	struct btrfs_csum_item *item;
 	struct extent_buffer *leaf;
 	u64 csum_offset = 0;
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 	int csums_in_item;
 
 	file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
@@ -270,7 +270,7 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
 	u32 diff;
 	int nblocks;
 	int count = 0;
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 
 	if (!fs_info->csum_root || (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
 		return BLK_STS_OK;
@@ -409,7 +409,7 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
 	int ret;
 	size_t size;
 	u64 csum_end;
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 
 	ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 	       IS_ALIGNED(end + 1, fs_info->sectorsize));
@@ -540,7 +540,7 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
 	int i;
 	u64 offset;
 	unsigned nofs_flag;
-	const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 
 	nofs_flag = memalloc_nofs_save();
 	sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
@@ -638,7 +638,7 @@ static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
 				       u64 bytenr, u64 len)
 {
 	struct extent_buffer *leaf;
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 	u64 csum_end;
 	u64 end_byte = bytenr + len;
 	u32 blocksize_bits = fs_info->sectorsize_bits;
@@ -692,7 +692,7 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
 	u64 csum_end;
 	struct extent_buffer *leaf;
 	int ret;
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 	u32 blocksize_bits = fs_info->sectorsize_bits;
 
 	ASSERT(root == fs_info->csum_root ||
@@ -847,7 +847,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 	int index = 0;
 	int found_next;
 	int ret;
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 
 	path = btrfs_alloc_path();
 	if (!path)

fs/btrfs/inode.c

@@ -2906,7 +2906,7 @@ static int check_data_csum(struct inode *inode, struct btrfs_io_bio *io_bio,
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	char *kaddr;
 	u32 len = fs_info->sectorsize;
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 	u8 *csum_expected;
 	u8 csum[BTRFS_CSUM_SIZE];
 
@@ -7825,7 +7825,7 @@ static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
 
 		csum_offset = file_offset - dip->logical_offset;
 		csum_offset >>= fs_info->sectorsize_bits;
-		csum_offset *= btrfs_super_csum_size(fs_info->super_copy);
+		csum_offset *= fs_info->csum_size;
 		btrfs_io_bio(bio)->csum = dip->csums + csum_offset;
 	}
 map:
@@ -7850,7 +7850,7 @@ static struct btrfs_dio_private *btrfs_create_dio_private(struct bio *dio_bio,
 	dip_size = sizeof(*dip);
 	if (!write && csum) {
 		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
-		const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+		const u16 csum_size = fs_info->csum_size;
 		size_t nblocks;
 
 		nblocks = dio_bio->bi_iter.bi_size >> fs_info->sectorsize_bits;

fs/btrfs/ordered-data.c

@@ -868,7 +868,7 @@ int btrfs_find_ordered_sum(struct btrfs_inode *inode, u64 offset,
 	struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 	unsigned long num_sectors;
 	unsigned long i;
-	const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 	int index = 0;
 
 	ordered = btrfs_lookup_ordered_extent(inode, offset);

fs/btrfs/ordered-data.h

@@ -137,7 +137,7 @@ 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);
-	int csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csum_size = fs_info->csum_size;
 
 	return sizeof(struct btrfs_ordered_sum) + num_sectors * csum_size;
 }

fs/btrfs/scrub.c

@@ -610,7 +610,7 @@ static noinline_for_stack struct scrub_ctx *scrub_setup_ctx(
 	atomic_set(&sctx->bios_in_flight, 0);
 	atomic_set(&sctx->workers_pending, 0);
 	atomic_set(&sctx->cancel_req, 0);
-	sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy);
+	sctx->csum_size = fs_info->csum_size;
 
 	spin_lock_init(&sctx->list_lock);
 	spin_lock_init(&sctx->stat_lock);

fs/btrfs/tree-checker.c

@@ -336,7 +336,7 @@ static int check_csum_item(struct extent_buffer *leaf, struct btrfs_key *key,
 {
 	struct btrfs_fs_info *fs_info = leaf->fs_info;
 	u32 sectorsize = fs_info->sectorsize;
-	u32 csumsize = btrfs_super_csum_size(fs_info->super_copy);
+	const u16 csumsize = fs_info->csum_size;
 
 	if (key->objectid != BTRFS_EXTENT_CSUM_OBJECTID) {
 		generic_err(leaf, slot,