[dm-devel] [2.6.29 PATCH 01/02] dm target: use module refcount directly

[Jonathan Brassow]

Reviewed-by: Jonathan Brassow <jbrassow at redhat.com>

  brassow

On Jan 7, 2009, at 2:41 PM, Alasdair G Kergon wrote:

> From: Cheng Renquan <crquan at gmail.com>
>
> The tt_internal's 'use' field is superfluous: the module's refcount  
> can do
> the work properly.  An acceptable side-effect is that this increases  
> the
> reference counts reported by 'lsmod'.
>
> Remove the superfluous test when removing a target module.
>
> Signed-off-by: Cheng Renquan <crquan at gmail.com>
> Reviewed-by: Alasdair G Kergon <agk at redhat.com>
> Signed-off-by: Alasdair G Kergon <agk at redhat.com>
> ---
> drivers/md/dm-target.c |   20 +++-----------------
> 1 files changed, 3 insertions(+), 17 deletions(-)
>
> Index: linux-2.6.28/drivers/md/dm-target.c
> ===================================================================
> --- linux-2.6.28.orig/drivers/md/dm-target.c	2009-01-07  
> 20:29:57.000000000 +0000
> +++ linux-2.6.28/drivers/md/dm-target.c	2009-01-07  
> 20:30:57.000000000 +0000
> @@ -18,7 +18,6 @@ struct tt_internal {
> 	struct target_type tt;
>
> 	struct list_head list;
> -	long use;
> };
>
> static LIST_HEAD(_targets);
> @@ -44,12 +43,8 @@ static struct tt_internal *get_target_ty
> 	down_read(&_lock);
>
> 	ti = __find_target_type(name);
> -	if (ti) {
> -		if ((ti->use == 0) && !try_module_get(ti->tt.module))
> -			ti = NULL;
> -		else
> -			ti->use++;
> -	}
> +	if (ti && !try_module_get(ti->tt.module))
> +		ti = NULL;
>
> 	up_read(&_lock);
> 	return ti;
> @@ -77,10 +72,7 @@ void dm_put_target_type(struct target_ty
> 	struct tt_internal *ti = (struct tt_internal *) t;
>
> 	down_read(&_lock);
> -	if (--ti->use == 0)
> -		module_put(ti->tt.module);
> -
> -	BUG_ON(ti->use < 0);
> +	module_put(ti->tt.module);
> 	up_read(&_lock);
>
> 	return;
> @@ -140,12 +132,6 @@ void dm_unregister_target(struct target_
> 		BUG();
> 	}
>
> -	if (ti->use) {
> -		DMCRIT("Attempt to unregister target still in use: %s",
> -		       t->name);
> -		BUG();
> -	}
> -
> 	list_del(&ti->list);
> 	kfree(ti);
>
>
> --
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