Re: [PATCH 3/3] btrfs: switch extent_buffer write_locks from atomic to int

[Nikolay Borisov <nborisov@suse.com>]

On 30.05.19 г. 19:31 ч., David Sterba wrote:
> The write_locks is either 0 or 1 and always updated under the lock,
> so we don't need the atomic_t semantics.
> 
> Signed-off-by: David Sterba <dsterba@suse.com>

Generally looks good, though my remark for patch2 remains.

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

> ---
>  fs/btrfs/extent_io.c  | 2 +-
>  fs/btrfs/extent_io.h  | 2 +-
>  fs/btrfs/locking.c    | 6 +++---
>  fs/btrfs/print-tree.c | 2 +-
>  4 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 71ee9e976307..6d75d4dcf473 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -4845,7 +4845,7 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
>  	eb->spinning_writers = 0;
>  	atomic_set(&eb->spinning_readers, 0);
>  	atomic_set(&eb->read_locks, 0);
> -	atomic_set(&eb->write_locks, 0);
> +	eb->write_locks = 0;
>  #endif
>  
>  	return eb;
> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
> index 5616b96c365d..844e595cde5b 100644
> --- a/fs/btrfs/extent_io.h
> +++ b/fs/btrfs/extent_io.h
> @@ -190,7 +190,7 @@ struct extent_buffer {
>  	int spinning_writers;
>  	atomic_t spinning_readers;
>  	atomic_t read_locks;
> -	atomic_t write_locks;
> +	int write_locks;
>  	struct list_head leak_list;
>  #endif
>  };
> diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
> index 270667627977..98fccce4208c 100644
> --- a/fs/btrfs/locking.c
> +++ b/fs/btrfs/locking.c
> @@ -58,17 +58,17 @@ static void btrfs_assert_tree_read_locked(struct extent_buffer *eb)
>  
>  static void btrfs_assert_tree_write_locks_get(struct extent_buffer *eb)
>  {
> -	atomic_inc(&eb->write_locks);
> +	eb->write_locks++;
>  }
>  
>  static void btrfs_assert_tree_write_locks_put(struct extent_buffer *eb)
>  {
> -	atomic_dec(&eb->write_locks);
> +	eb->write_locks--;
>  }
>  
>  void btrfs_assert_tree_locked(struct extent_buffer *eb)
>  {
> -	BUG_ON(!atomic_read(&eb->write_locks));
> +	BUG_ON(!eb->write_locks);
>  }
>  
>  #else
> diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
> index c5cc435ed39a..9cb50577d982 100644
> --- a/fs/btrfs/print-tree.c
> +++ b/fs/btrfs/print-tree.c
> @@ -153,7 +153,7 @@ static void print_eb_refs_lock(struct extent_buffer *eb)
>  #ifdef CONFIG_BTRFS_DEBUG
>  	btrfs_info(eb->fs_info,
>  "refs %u lock (w:%d r:%d bw:%d br:%d sw:%d sr:%d) lock_owner %u current %u",
> -		   atomic_read(&eb->refs), atomic_read(&eb->write_locks),
> +		   atomic_read(&eb->refs), eb->write_locks,
>  		   atomic_read(&eb->read_locks),
>  		   eb->blocking_writers,
>  		   atomic_read(&eb->blocking_readers),
>