diff mbox series

[3/3] btrfs: add __pure attribute to functions

Message ID faadfd67d10404a342d91a910e40fc2d0f5f4e6c.1569587835.git.dsterba@suse.com (mailing list archive)
State New, archived
Headers show
Series Coldify, constify, purify (function attributes) | expand

Commit Message

David Sterba Oct. 1, 2019, 5:57 p.m. UTC 
The attribute is more relaxed than const and the functions could
dereference pointers, as long as the observable state is not changed. We
do have such functions, based on -Wsuggest-attribute=pure .

The visible effects of this patch are negligible, there are differences
in the assembly but hard to summarize.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/async-thread.c | 6 ++----
 fs/btrfs/async-thread.h | 4 ++--
 fs/btrfs/ctree.c        | 2 +-
 fs/btrfs/ctree.h        | 4 ++--
 fs/btrfs/dev-replace.c  | 2 +-
 fs/btrfs/dev-replace.h  | 2 +-
 fs/btrfs/ioctl.c        | 2 +-
 fs/btrfs/space-info.c   | 2 +-
 fs/btrfs/space-info.h   | 2 +-
 9 files changed, 12 insertions(+), 14 deletions(-)

Comments

Nikolay Borisov Oct. 2, 2019, 11:09 a.m. UTC | #1 
On 1.10.19 г. 20:57 ч., David Sterba wrote:
> The attribute is more relaxed than const and the functions could
> dereference pointers, as long as the observable state is not changed. We
> do have such functions, based on -Wsuggest-attribute=pure .
> 
> The visible effects of this patch are negligible, there are differences
> in the assembly but hard to summarize.
> 
> Signed-off-by: David Sterba <dsterba@suse.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

one remark: I'm not sure the attribute needs to be duplicated in the
declaration and definition.

> ---
>  fs/btrfs/async-thread.c | 6 ++----
>  fs/btrfs/async-thread.h | 4 ++--
>  fs/btrfs/ctree.c        | 2 +-
>  fs/btrfs/ctree.h        | 4 ++--
>  fs/btrfs/dev-replace.c  | 2 +-
>  fs/btrfs/dev-replace.h  | 2 +-
>  fs/btrfs/ioctl.c        | 2 +-
>  fs/btrfs/space-info.c   | 2 +-
>  fs/btrfs/space-info.h   | 2 +-
>  9 files changed, 12 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
> index b97ae1b03417..1d32a07bb2d1 100644
> --- a/fs/btrfs/async-thread.c
> +++ b/fs/btrfs/async-thread.c
> @@ -53,14 +53,12 @@ struct btrfs_workqueue {
>  	struct __btrfs_workqueue *high;
>  };
>  
> -struct btrfs_fs_info *
> -btrfs_workqueue_owner(const struct __btrfs_workqueue *wq)
> +struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct __btrfs_workqueue *wq)
>  {
>  	return wq->fs_info;
>  }
>  
> -struct btrfs_fs_info *
> -btrfs_work_owner(const struct btrfs_work *work)
> +struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work)
>  {
>  	return work->wq->fs_info;
>  }
> diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
> index c5bf2b117c05..a4434301d84d 100644
> --- a/fs/btrfs/async-thread.h
> +++ b/fs/btrfs/async-thread.h
> @@ -41,8 +41,8 @@ void btrfs_queue_work(struct btrfs_workqueue *wq,
>  void btrfs_destroy_workqueue(struct btrfs_workqueue *wq);
>  void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max);
>  void btrfs_set_work_high_priority(struct btrfs_work *work);
> -struct btrfs_fs_info *btrfs_work_owner(const struct btrfs_work *work);
> -struct btrfs_fs_info *btrfs_workqueue_owner(const struct __btrfs_workqueue *wq);
> +struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work);
> +struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct __btrfs_workqueue *wq);
>  bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq);
>  
>  #endif
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index f2f9cf1149a4..3a4d8e27e565 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -1538,7 +1538,7 @@ static int comp_keys(const struct btrfs_disk_key *disk,
>  /*
>   * same as comp_keys only with two btrfs_key's
>   */
> -int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
> +int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
>  {
>  	if (k1->objectid > k2->objectid)
>  		return 1;
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 793085770c84..df0f2de69991 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -2511,7 +2511,7 @@ void btrfs_wait_for_snapshot_creation(struct btrfs_root *root);
>  /* ctree.c */
>  int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
>  		     int level, int *slot);
> -int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);
> +int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);
>  int btrfs_previous_item(struct btrfs_root *root,
>  			struct btrfs_path *path, u64 min_objectid,
>  			int type);
> @@ -2912,7 +2912,7 @@ long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
>  long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
>  int btrfs_ioctl_get_supported_features(void __user *arg);
>  void btrfs_sync_inode_flags_to_i_flags(struct inode *inode);
> -int btrfs_is_empty_uuid(u8 *uuid);
> +int __pure btrfs_is_empty_uuid(u8 *uuid);
>  int btrfs_defrag_file(struct inode *inode, struct file *file,
>  		      struct btrfs_ioctl_defrag_range_args *range,
>  		      u64 newer_than, unsigned long max_pages);
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index 48890826b5e6..f639dde2a679 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -986,7 +986,7 @@ static int btrfs_dev_replace_kthread(void *data)
>  	return 0;
>  }
>  
> -int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
> +int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
>  {
>  	if (!dev_replace->is_valid)
>  		return 0;
> diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h
> index 78c5d8f1adda..60b70dacc299 100644
> --- a/fs/btrfs/dev-replace.h
> +++ b/fs/btrfs/dev-replace.h
> @@ -17,6 +17,6 @@ void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
>  int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info);
>  void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info);
>  int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info);
> -int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace);
> +int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace);
>  
>  #endif
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index de730e56d3f5..55b41d5e7ea9 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -541,7 +541,7 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
>  	return 0;
>  }
>  
> -int btrfs_is_empty_uuid(u8 *uuid)
> +int __pure btrfs_is_empty_uuid(u8 *uuid)
>  {
>  	int i;
>  
> diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
> index 98dc092a905e..f32993efbf61 100644
> --- a/fs/btrfs/space-info.c
> +++ b/fs/btrfs/space-info.c
> @@ -10,7 +10,7 @@
>  #include "transaction.h"
>  #include "block-group.h"
>  
> -u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
> +u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
>  			  bool may_use_included)
>  {
>  	ASSERT(s_info);
> diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
> index 8867e84aa33d..2d8c811a9792 100644
> --- a/fs/btrfs/space-info.h
> +++ b/fs/btrfs/space-info.h
> @@ -116,7 +116,7 @@ void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags,
>  			     struct btrfs_space_info **space_info);
>  struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
>  					       u64 flags);
> -u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
> +u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
>  			  bool may_use_included);
>  void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
>  void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
>
diff mbox series

Patch

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index b97ae1b03417..1d32a07bb2d1 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -53,14 +53,12 @@  struct btrfs_workqueue {
 	struct __btrfs_workqueue *high;
 };
 
-struct btrfs_fs_info *
-btrfs_workqueue_owner(const struct __btrfs_workqueue *wq)
+struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct __btrfs_workqueue *wq)
 {
 	return wq->fs_info;
 }
 
-struct btrfs_fs_info *
-btrfs_work_owner(const struct btrfs_work *work)
+struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work)
 {
 	return work->wq->fs_info;
 }
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index c5bf2b117c05..a4434301d84d 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -41,8 +41,8 @@  void btrfs_queue_work(struct btrfs_workqueue *wq,
 void btrfs_destroy_workqueue(struct btrfs_workqueue *wq);
 void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max);
 void btrfs_set_work_high_priority(struct btrfs_work *work);
-struct btrfs_fs_info *btrfs_work_owner(const struct btrfs_work *work);
-struct btrfs_fs_info *btrfs_workqueue_owner(const struct __btrfs_workqueue *wq);
+struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work);
+struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct __btrfs_workqueue *wq);
 bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq);
 
 #endif
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f2f9cf1149a4..3a4d8e27e565 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1538,7 +1538,7 @@  static int comp_keys(const struct btrfs_disk_key *disk,
 /*
  * same as comp_keys only with two btrfs_key's
  */
-int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
+int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
 {
 	if (k1->objectid > k2->objectid)
 		return 1;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 793085770c84..df0f2de69991 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2511,7 +2511,7 @@  void btrfs_wait_for_snapshot_creation(struct btrfs_root *root);
 /* ctree.c */
 int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
 		     int level, int *slot);
-int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);
+int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);
 int btrfs_previous_item(struct btrfs_root *root,
 			struct btrfs_path *path, u64 min_objectid,
 			int type);
@@ -2912,7 +2912,7 @@  long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 int btrfs_ioctl_get_supported_features(void __user *arg);
 void btrfs_sync_inode_flags_to_i_flags(struct inode *inode);
-int btrfs_is_empty_uuid(u8 *uuid);
+int __pure btrfs_is_empty_uuid(u8 *uuid);
 int btrfs_defrag_file(struct inode *inode, struct file *file,
 		      struct btrfs_ioctl_defrag_range_args *range,
 		      u64 newer_than, unsigned long max_pages);
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 48890826b5e6..f639dde2a679 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -986,7 +986,7 @@  static int btrfs_dev_replace_kthread(void *data)
 	return 0;
 }
 
-int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
+int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
 {
 	if (!dev_replace->is_valid)
 		return 0;
diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h
index 78c5d8f1adda..60b70dacc299 100644
--- a/fs/btrfs/dev-replace.h
+++ b/fs/btrfs/dev-replace.h
@@ -17,6 +17,6 @@  void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
 int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info);
 void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info);
 int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info);
-int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace);
+int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace);
 
 #endif
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index de730e56d3f5..55b41d5e7ea9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -541,7 +541,7 @@  static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 	return 0;
 }
 
-int btrfs_is_empty_uuid(u8 *uuid)
+int __pure btrfs_is_empty_uuid(u8 *uuid)
 {
 	int i;
 
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 98dc092a905e..f32993efbf61 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -10,7 +10,7 @@ 
 #include "transaction.h"
 #include "block-group.h"
 
-u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
+u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
 			  bool may_use_included)
 {
 	ASSERT(s_info);
diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
index 8867e84aa33d..2d8c811a9792 100644
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -116,7 +116,7 @@  void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags,
 			     struct btrfs_space_info **space_info);
 struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
 					       u64 flags);
-u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
+u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
 			  bool may_use_included);
 void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
 void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,