RE: [PATCH] elevator: fix double release for elevator module

2015-04-23 Thread Chao Yu 
Hi Jens and Jeff,

Thanks for your review and help! :)

Regards,

> -Original Message-
> From: Jens Axboe [mailto:ax...@kernel.dk]
> Sent: Friday, April 24, 2015 12:49 AM
> To: Jeff Moyer; Chao Yu
> Cc: linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] elevator: fix double release for elevator module
> 
> On 04/23/2015 08:59 AM, Jeff Moyer wrote:
> > Chao Yu  writes:
> >
> >> Our issue is descripted in below call path:
> >> ->elevator_init
> >>   ->elevator_init_fn
> >>->{cfq,deadline,noop}_init_queue
> >> ->elevator_alloc
> >>  ->kzalloc_node
> >> fail to call kzalloc_node and then put module in elevator_alloc;
> >> fail to call elevator_init_fn and then put module again in elevator_init.
> >>
> >> Remove elevator_put invoking in error path of elevator_alloc to avoid
> >> double release issue.
> >>
> >> Signed-off-by: Chao Yu 
> >> ---
> >>   block/elevator.c | 5 +
> >>   1 file changed, 1 insertion(+), 4 deletions(-)
> >>
> >> diff --git a/block/elevator.c b/block/elevator.c
> >> index d146a5e..8985038 100644
> >> --- a/block/elevator.c
> >> +++ b/block/elevator.c
> >> @@ -157,7 +157,7 @@ struct elevator_queue *elevator_alloc(struct 
> >> request_queue *q,
> >>
> >>eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node);
> >>if (unlikely(!eq))
> >> -  goto err;
> >> +  return NULL;
> >>
> >>eq->type = e;
> >>kobject_init(&eq->kobj, &elv_ktype);
> >> @@ -165,9 +165,6 @@ struct elevator_queue *elevator_alloc(struct 
> >> request_queue *q,
> >>hash_init(eq->hash);
> >>
> >>return eq;
> >> -err:
> >> -  elevator_put(e);
> >> -  return NULL;
> >>   }
> >>   EXPORT_SYMBOL(elevator_alloc);
> >
> > You could have posted the two patches together, as they are related.
> > Anyway, looks good to me.
> >
> > Reviewed-by: Jeff Moyer 
> 
> Agree, it should be one patch. I've combined them, and applied the fix
> for 4.1. Thanks.
> 
> --
> Jens Axboe

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Re: [PATCH] elevator: fix double release for elevator module

2015-04-23 Thread Jens Axboe 

On 04/23/2015 08:59 AM, Jeff Moyer wrote:

Chao Yu  writes:


Our issue is descripted in below call path:
->elevator_init
  ->elevator_init_fn
   ->{cfq,deadline,noop}_init_queue
->elevator_alloc
 ->kzalloc_node
fail to call kzalloc_node and then put module in elevator_alloc;
fail to call elevator_init_fn and then put module again in elevator_init.

Remove elevator_put invoking in error path of elevator_alloc to avoid
double release issue.

Signed-off-by: Chao Yu 
---
  block/elevator.c | 5 +
  1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/block/elevator.c b/block/elevator.c
index d146a5e..8985038 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -157,7 +157,7 @@ struct elevator_queue *elevator_alloc(struct request_queue 
*q,

eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node);
if (unlikely(!eq))
-   goto err;
+   return NULL;

eq->type = e;
kobject_init(&eq->kobj, &elv_ktype);
@@ -165,9 +165,6 @@ struct elevator_queue *elevator_alloc(struct request_queue 
*q,
hash_init(eq->hash);

return eq;
-err:
-   elevator_put(e);
-   return NULL;
  }
  EXPORT_SYMBOL(elevator_alloc);


You could have posted the two patches together, as they are related.
Anyway, looks good to me.

Reviewed-by: Jeff Moyer 


Agree, it should be one patch. I've combined them, and applied the fix 
for 4.1. Thanks.


--
Jens Axboe

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Re: [PATCH] elevator: fix double release for elevator module

2015-04-23 Thread Jeff Moyer 
Chao Yu  writes:

> Our issue is descripted in below call path:
> ->elevator_init
>  ->elevator_init_fn
>   ->{cfq,deadline,noop}_init_queue
>->elevator_alloc
> ->kzalloc_node
>fail to call kzalloc_node and then put module in elevator_alloc;
> fail to call elevator_init_fn and then put module again in elevator_init.
>
> Remove elevator_put invoking in error path of elevator_alloc to avoid
> double release issue.
>
> Signed-off-by: Chao Yu 
> ---
>  block/elevator.c | 5 +
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/block/elevator.c b/block/elevator.c
> index d146a5e..8985038 100644
> --- a/block/elevator.c
> +++ b/block/elevator.c
> @@ -157,7 +157,7 @@ struct elevator_queue *elevator_alloc(struct 
> request_queue *q,
>  
>   eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node);
>   if (unlikely(!eq))
> - goto err;
> + return NULL;
>  
>   eq->type = e;
>   kobject_init(&eq->kobj, &elv_ktype);
> @@ -165,9 +165,6 @@ struct elevator_queue *elevator_alloc(struct 
> request_queue *q,
>   hash_init(eq->hash);
>  
>   return eq;
> -err:
> - elevator_put(e);
> - return NULL;
>  }
>  EXPORT_SYMBOL(elevator_alloc);

You could have posted the two patches together, as they are related.
Anyway, looks good to me.

Reviewed-by: Jeff Moyer 
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