[PATCH] kdbus: Make kdbus_bus_unref() return void

[PATCH] kdbus: Make kdbus_bus_unref() return void

[Tobias Klauser]

kdbus_bus_unref() always returns NULL and none of its callers use the
return value, so make it return void.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
---
 ipc/kdbus/bus.c | 5 +----
 ipc/kdbus/bus.h | 2 +-
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/ipc/kdbus/bus.c b/ipc/kdbus/bus.c
index 9d0679e..dce7b08 100644
--- a/ipc/kdbus/bus.c
+++ b/ipc/kdbus/bus.c
@@ -202,14 +202,11 @@ struct kdbus_bus *kdbus_bus_ref(struct kdbus_bus *bus)
  *
  * Release a reference. If the reference count drops to 0, the bus will be
  * freed.
- *
- * Return: NULL
  */
-struct kdbus_bus *kdbus_bus_unref(struct kdbus_bus *bus)
+void kdbus_bus_unref(struct kdbus_bus *bus)
 {
 	if (bus)
 		kdbus_node_unref(&bus->node);
-	return NULL;
 }
 
 /**
diff --git a/ipc/kdbus/bus.h b/ipc/kdbus/bus.h
index 5bea5ef..266af60 100644
--- a/ipc/kdbus/bus.h
+++ b/ipc/kdbus/bus.h
@@ -84,7 +84,7 @@ struct kdbus_bus {
 };
 
 struct kdbus_bus *kdbus_bus_ref(struct kdbus_bus *bus);
-struct kdbus_bus *kdbus_bus_unref(struct kdbus_bus *bus);
+void kdbus_bus_unref(struct kdbus_bus *bus);
 
 struct kdbus_conn *kdbus_bus_find_conn_by_id(struct kdbus_bus *bus, u64 id);
 void kdbus_bus_broadcast(struct kdbus_bus *bus,
-- 
2.2.2

Re: [PATCH] kdbus: Make kdbus_bus_unref() return void

[David Herrmann]

Hi

On Wed, Apr 22, 2015 at 1:50 PM, Tobias Klauser <tklauser@distanz.ch> wrote:
> kdbus_bus_unref() always returns NULL and none of its callers use the
> return value, so make it return void.
>
> Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

All our destructors return NULL, which allows simple assignment during
destruction:
  foo->bus = kdbus_bus_unref(foo->bus);
And our destructors ignore NULL, so no reason to conditionalize the
call to unref(). This simplifies our error-paths a lot, and I'd like
to keep it that way.

I'd prefer to stay uniform across our code-base and keep returning
NULL. It's neither a fast-path, nor do return values require any
memory writes (usually register passing, iirc).

Thanks
David

> ---
>  ipc/kdbus/bus.c | 5 +----
>  ipc/kdbus/bus.h | 2 +-
>  2 files changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/ipc/kdbus/bus.c b/ipc/kdbus/bus.c
> index 9d0679e..dce7b08 100644
> --- a/ipc/kdbus/bus.c
> +++ b/ipc/kdbus/bus.c
> @@ -202,14 +202,11 @@ struct kdbus_bus *kdbus_bus_ref(struct kdbus_bus *bus)
>   *
>   * Release a reference. If the reference count drops to 0, the bus will be
>   * freed.
> - *
> - * Return: NULL
>   */
> -struct kdbus_bus *kdbus_bus_unref(struct kdbus_bus *bus)
> +void kdbus_bus_unref(struct kdbus_bus *bus)
>  {
>         if (bus)
>                 kdbus_node_unref(&bus->node);
> -       return NULL;
>  }
>
>  /**
> diff --git a/ipc/kdbus/bus.h b/ipc/kdbus/bus.h
> index 5bea5ef..266af60 100644
> --- a/ipc/kdbus/bus.h
> +++ b/ipc/kdbus/bus.h
> @@ -84,7 +84,7 @@ struct kdbus_bus {
>  };
>
>  struct kdbus_bus *kdbus_bus_ref(struct kdbus_bus *bus);
> -struct kdbus_bus *kdbus_bus_unref(struct kdbus_bus *bus);
> +void kdbus_bus_unref(struct kdbus_bus *bus);
>
>  struct kdbus_conn *kdbus_bus_find_conn_by_id(struct kdbus_bus *bus, u64 id);
>  void kdbus_bus_broadcast(struct kdbus_bus *bus,
> --
> 2.2.2
>
>

Re: [PATCH] kdbus: Make kdbus_bus_unref() return void

[Tobias Klauser]

On 2015-04-22 at 14:01:05 +0200, David Herrmann <dh.herrmann@gmail.com> wrote:
> Hi
> 
> On Wed, Apr 22, 2015 at 1:50 PM, Tobias Klauser <tklauser@distanz.ch> wrote:
> > kdbus_bus_unref() always returns NULL and none of its callers use the
> > return value, so make it return void.
> >
> > Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
> 
> All our destructors return NULL, which allows simple assignment during
> destruction:
>   foo->bus = kdbus_bus_unref(foo->bus);
> And our destructors ignore NULL, so no reason to conditionalize the
> call to unref(). This simplifies our error-paths a lot, and I'd like
> to keep it that way.

Thanks for the explanation. I didn't consider this - and didn't even
look at the other *_unref() for that matter :(