[PATCH v3] block: wrong return value

[PATCH v3] block: wrong return value

[Sudip Mukherjee]

while compiling integer err was showing as a set but unused variable.
elevator_init_fn can be either cfq_init_queue or deadline_init_queue
or noop_init_queue.
all three of these functions are returning -ENOMEM if they fail to
allocate the queue.
so we should actually be returning the error code rather than
returning 0 always.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
---

change in v2: added elevator_put
change in v3: remove unneeded initialization of err

 block/elevator.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/elevator.c b/block/elevator.c
index 24c28b6..afa3b03 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -229,7 +229,9 @@ int elevator_init(struct request_queue *q, char *name)
 	}
 
 	err = e->ops.elevator_init_fn(q, e);
-	return 0;
+	if (err)
+		elevator_put(e);
+	return err;
 }
 EXPORT_SYMBOL(elevator_init);
 
-- 
1.8.1.2

Re: [PATCH v3] block: wrong return value

[Sudip Mukherjee]

On Thu, Oct 23, 2014 at 10:16:48PM +0530, Sudip Mukherjee wrote:
> while compiling integer err was showing as a set but unused variable.
> elevator_init_fn can be either cfq_init_queue or deadline_init_queue
> or noop_init_queue.
> all three of these functions are returning -ENOMEM if they fail to
> allocate the queue.
> so we should actually be returning the error code rather than
> returning 0 always.
i have one doubt. shouldn't this patch be marked for stable also?

thanks
sudip
> 
> Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
> ---
> 
> change in v2: added elevator_put
> change in v3: remove unneeded initialization of err
> 
>  block/elevator.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/block/elevator.c b/block/elevator.c
> index 24c28b6..afa3b03 100644
> --- a/block/elevator.c
> +++ b/block/elevator.c
> @@ -229,7 +229,9 @@ int elevator_init(struct request_queue *q, char *name)
>  	}
>  
>  	err = e->ops.elevator_init_fn(q, e);
> -	return 0;
> +	if (err)
> +		elevator_put(e);
> +	return err;
>  }
>  EXPORT_SYMBOL(elevator_init);
>  
> -- 
> 1.8.1.2
> 

Re: [PATCH v3] block: wrong return value

[Jens Axboe]

On 2014-10-28 11:22, Sudip Mukherjee wrote:
> On Thu, Oct 23, 2014 at 10:16:48PM +0530, Sudip Mukherjee wrote:
>> while compiling integer err was showing as a set but unused variable.
>> elevator_init_fn can be either cfq_init_queue or deadline_init_queue
>> or noop_init_queue.
>> all three of these functions are returning -ENOMEM if they fail to
>> allocate the queue.
>> so we should actually be returning the error code rather than
>> returning 0 always.
> i have one doubt. shouldn't this patch be marked for stable also?

It would not hurt to mark it as stable, but on the other hand, this 
probably never triggered a problem for anyone. So it's not a critical 
fix by any stretch.

-- 
Jens Axboe