[PATCH v2] btrfs: removed unused return variable

[PATCH v2] btrfs: removed unused return variable

[Aliasgar Surti]

From: Aliasgar Surti <aliasgar.surti500@gmail.com>

Removed unused return variable and replaced it with returning
the value directly

Signed-off-by: Aliasgar Surti <aliasgar.surti500@gmail.com>
---
v2: Made btrfs_destroy_delayed_refs() as void and removed its declaration
---
 fs/btrfs/disk-io.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 044981c..0a8243a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -52,8 +52,6 @@
 static const struct extent_io_ops btree_extent_io_ops;
 static void end_workqueue_fn(struct btrfs_work *work);
 static void btrfs_destroy_ordered_extents(struct btrfs_root *root);
-static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
-				      struct btrfs_fs_info *fs_info);
 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
 static int btrfs_destroy_marked_extents(struct btrfs_fs_info *fs_info,
 					struct extent_io_tree *dirty_pages,
@@ -4249,13 +4247,12 @@ static void btrfs_destroy_all_ordered_extents(struct btrfs_fs_info *fs_info)
 	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 }
 
-static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
+static void btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 				      struct btrfs_fs_info *fs_info)
 {
 	struct rb_node *node;
 	struct btrfs_delayed_ref_root *delayed_refs;
 	struct btrfs_delayed_ref_node *ref;
-	int ret = 0;
 
 	delayed_refs = &trans->delayed_refs;
 
@@ -4263,7 +4260,7 @@ static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 	if (atomic_read(&delayed_refs->num_entries) == 0) {
 		spin_unlock(&delayed_refs->lock);
 		btrfs_info(fs_info, "delayed_refs has NO entry");
-		return ret;
+		return;
 	}
 
 	while ((node = rb_first_cached(&delayed_refs->href_root)) != NULL) {
@@ -4306,8 +4303,6 @@ static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 	}
 
 	spin_unlock(&delayed_refs->lock);
-
-	return ret;
 }
 
 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
-- 
2.7.4

Re: [PATCH v2] btrfs: removed unused return variable

[Nikolay Borisov]

On 30.09.19 г. 16:00 ч., Aliasgar Surti wrote:
> From: Aliasgar Surti <aliasgar.surti500@gmail.com>
> 
> Removed unused return variable and replaced it with returning
> the value directly

The changelog could be expanded, something like:

btrfs_destroy_delayed_refs always returns 0 so it can be converted to
void. While at it also remove the unnecessary forward declaration in
disk-io.c

> 
> Signed-off-by: Aliasgar Surti <aliasgar.surti500@gmail.com>

Code wise it's ok:

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

> ---
> v2: Made btrfs_destroy_delayed_refs() as void and removed its declaration
> ---
>  fs/btrfs/disk-io.c | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 044981c..0a8243a 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -52,8 +52,6 @@
>  static const struct extent_io_ops btree_extent_io_ops;
>  static void end_workqueue_fn(struct btrfs_work *work);
>  static void btrfs_destroy_ordered_extents(struct btrfs_root *root);
> -static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
> -				      struct btrfs_fs_info *fs_info);
>  static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
>  static int btrfs_destroy_marked_extents(struct btrfs_fs_info *fs_info,
>  					struct extent_io_tree *dirty_pages,
> @@ -4249,13 +4247,12 @@ static void btrfs_destroy_all_ordered_extents(struct btrfs_fs_info *fs_info)
>  	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
>  }
>  
> -static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
> +static void btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
>  				      struct btrfs_fs_info *fs_info)
                                       ^^^^^^
nit: It's good practice to also adjust the alignment of following lines.

>  {
>  	struct rb_node *node;
>  	struct btrfs_delayed_ref_root *delayed_refs;
>  	struct btrfs_delayed_ref_node *ref;
> -	int ret = 0;
>  
>  	delayed_refs = &trans->delayed_refs;
>  
> @@ -4263,7 +4260,7 @@ static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
>  	if (atomic_read(&delayed_refs->num_entries) == 0) {
>  		spin_unlock(&delayed_refs->lock);
>  		btrfs_info(fs_info, "delayed_refs has NO entry");
> -		return ret;
> +		return;
>  	}
>  
>  	while ((node = rb_first_cached(&delayed_refs->href_root)) != NULL) {
> @@ -4306,8 +4303,6 @@ static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
>  	}
>  
>  	spin_unlock(&delayed_refs->lock);
> -
> -	return ret;
>  }
>  
>  static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
> 

Re: [PATCH v2] btrfs: removed unused return variable

[David Sterba]

On Mon, Sep 30, 2019 at 06:30:21PM +0530, Aliasgar Surti wrote:
> From: Aliasgar Surti <aliasgar.surti500@gmail.com>
> 
> Removed unused return variable and replaced it with returning
> the value directly

This change has been sent several times and I give the same answer each
time:

https://lore.kernel.org/linux-btrfs/20190418154913.GO20156@twin.jikos.cz/

"When switching a fuction to return void, please check the whole
callgraph for functions that do not properly handler errors and do
BUG_ON. You won't see errors passed from them so this gives the
impression no error handling is needed in the caller.

This has been sent in the past, so I can point you to the 2nd paragraph
in
https://lore.kernel.org/linux-btrfs/20180815124425.GM24025@twin.jikos.cz/

hint: btrfs_pin_extent"

Re: [PATCH v2] btrfs: removed unused return variable

[Aliasgar Surti]

On Mon, Sep 30, 2019 at 03:33:35PM +0200, David Sterba wrote:
> On Mon, Sep 30, 2019 at 06:30:21PM +0530, Aliasgar Surti wrote:
> > From: Aliasgar Surti <aliasgar.surti500@gmail.com>
> > 
> > Removed unused return variable and replaced it with returning
> > the value directly
> 
> This change has been sent several times and I give the same answer each
> time:
> 
> https://lore.kernel.org/linux-btrfs/20190418154913.GO20156@twin.jikos.cz/
> 
> "When switching a fuction to return void, please check the whole
> callgraph for functions that do not properly handler errors and do
> BUG_ON. You won't see errors passed from them so this gives the
> impression no error handling is needed in the caller.
> 
> This has been sent in the past, so I can point you to the 2nd paragraph
> in
> https://lore.kernel.org/linux-btrfs/20180815124425.GM24025@twin.jikos.cz/
> 
> hint: btrfs_pin_extent"

Okay, reverted back the changes and submitted v3.

Thanks,
Aliasgar