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authorDavid Sterba <dsterba@suse.com>2019-10-01 19:57:37 +0200
committerDavid Sterba <dsterba@suse.com>2019-11-18 12:46:52 +0100
commit4143cb8b6f00910e73a7503fd922211b9f08cf48 (patch)
tree6e61a1f2ac756102f27cf4dc9a0ca19359259c81
parentb105e92755b448efd4800e3415dfeae5ad8054e9 (diff)
btrfs: add const function attribute
For some reason the attribute is called __attribute_const__ and not __const, marks functions that have no observable effects on program state, IOW not reading pointers, just the arguments and calculating a value. Allows the compiler to do some optimizations, based on -Wsuggest-attribute=const . The effects are rather small, though, about 60 bytes decrese of btrfs.ko. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/ctree.h2
-rw-r--r--fs/btrfs/super.c2
-rw-r--r--fs/btrfs/volumes.c2
-rw-r--r--fs/btrfs/volumes.h2
4 files changed, 4 insertions, 4 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b23fb083a1d5..8d7ac1cd49b4 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3141,7 +3141,7 @@ __cold
void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
unsigned int line, int errno, const char *fmt, ...);
-const char *btrfs_decode_error(int errno);
+const char * __attribute_const__ btrfs_decode_error(int errno);
__cold
void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 9c0c53e7d0fc..144933c9b507 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -66,7 +66,7 @@ static struct file_system_type btrfs_root_fs_type;
static int btrfs_remount(struct super_block *sb, int *flags, char *data);
-const char *btrfs_decode_error(int errno)
+const char * __attribute_const__ btrfs_decode_error(int errno)
{
char *errstr = "unknown";
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 173427731a69..d09371b0cdf9 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -297,7 +297,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
DEFINE_MUTEX(uuid_mutex);
static LIST_HEAD(fs_uuids);
-struct list_head *btrfs_get_fs_uuids(void)
+struct list_head * __attribute_const__ btrfs_get_fs_uuids(void)
{
return &fs_uuids;
}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index a7da1f3e3627..0ae0677a8d86 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -571,7 +571,7 @@ static inline enum btrfs_raid_types btrfs_bg_flags_to_raid_index(u64 flags)
void btrfs_commit_device_sizes(struct btrfs_transaction *trans);
-struct list_head *btrfs_get_fs_uuids(void);
+struct list_head * __attribute_const__ btrfs_get_fs_uuids(void);
void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info);
void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info);
bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,