linux-kernel - Re: [PATCH 2/2] lightnvm: refactor dev->online_target to global nvm

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Date:	Sat, 16 Apr 2016 16:20:05 +0200
From:	Matias Bjørling <mb@...htnvm.io>
To:	"Simon A. F. Lund" <slund@...xlabs.com>,
	linux-block@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] lightnvm: refactor dev->online_target to global
 nvm_targets

On 04/13/2016 02:15 PM, Simon A. F. Lund wrote:
> A target name must be unique. However, a per-device registration of
> targets is maintained on a dev->online_targets list, with a per-device
> search for targets upon registration.
> 
> This results in a name collision when two targets, with the same name,
> are created on two different targets, where the per-device list is not
> shared.
> 
> Signed-off-by: Simon A. F. Lund <slund@...xlabs.com>
> ---
>  drivers/lightnvm/core.c  | 47 +++++++++++++++++++++++++----------------------
>  include/linux/lightnvm.h |  1 -
>  2 files changed, 25 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 240b473..0296223 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -33,8 +33,20 @@
>  static LIST_HEAD(nvm_tgt_types);
>  static LIST_HEAD(nvm_mgrs);
>  static LIST_HEAD(nvm_devices);
> +static LIST_HEAD(nvm_targets);
>  static DECLARE_RWSEM(nvm_lock);
>  
> +static struct nvm_target *nvm_find_target(const char *name)
> +{
> +	struct nvm_target *tgt;
> +
> +	list_for_each_entry(tgt, &nvm_targets, list)
> +		if (!strcmp(name, tgt->disk->disk_name))
> +			return tgt;
> +
> +	return NULL;
> +}
> +
>  static struct nvm_tgt_type *nvm_find_target_type(const char *name)
>  {
>  	struct nvm_tgt_type *tt;
> @@ -564,7 +576,6 @@ static int nvm_core_init(struct nvm_dev *dev)
>  		goto err_fmtype;
>  	}
>  
> -	INIT_LIST_HEAD(&dev->online_targets);
>  	mutex_init(&dev->mlock);
>  	spin_lock_init(&dev->lock);
>  
> @@ -744,12 +755,11 @@ static int nvm_create_target(struct nvm_dev *dev,
>  		return -EINVAL;
>  	}
>  
> -	list_for_each_entry(t, &dev->online_targets, list) {
> -		if (!strcmp(create->tgtname, t->disk->disk_name)) {
> -			pr_err("nvm: target name already exists.\n");
> -			up_write(&nvm_lock);
> -			return -EINVAL;
> -		}
> +	t = nvm_find_target(create->tgtname);
> +	if (t) {
> +		pr_err("nvm: target name already exists.\n");
> +		up_write(&nvm_lock);
> +		return -EINVAL;
>  	}
>  	up_write(&nvm_lock);
>  
> @@ -789,7 +799,7 @@ static int nvm_create_target(struct nvm_dev *dev,
>  	t->disk = tdisk;
>  
>  	down_write(&nvm_lock);
> -	list_add_tail(&t->list, &dev->online_targets);
> +	list_add_tail(&t->list, &nvm_targets);
>  	up_write(&nvm_lock);
>  
>  	return 0;
> @@ -852,26 +862,19 @@ static int __nvm_configure_create(struct nvm_ioctl_create *create)
>  
>  static int __nvm_configure_remove(struct nvm_ioctl_remove *remove)
>  {
> -	struct nvm_target *t = NULL;
> -	struct nvm_dev *dev;
> -	int ret = -1;
> +	struct nvm_target *t;
>  
>  	down_write(&nvm_lock);
> -	list_for_each_entry(dev, &nvm_devices, devices)
> -		list_for_each_entry(t, &dev->online_targets, list) {
> -			if (!strcmp(remove->tgtname, t->disk->disk_name)) {
> -				nvm_remove_target(t);
> -				ret = 0;
> -				break;
> -			}
> -		}
> -	up_write(&nvm_lock);
> -
> -	if (ret) {
> +	t = nvm_find_target(remove->tgtname);
> +	if (!t) {
>  		pr_err("nvm: target \"%s\" doesn't exist.\n", remove->tgtname);
> +		up_write(&nvm_lock);
>  		return -EINVAL;
>  	}
>  
> +	nvm_remove_target(t);
> +	up_write(&nvm_lock);
> +
>  	return 0;
>  }
>  
> diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
> index 497da91..5eabdba 100644
> --- a/include/linux/lightnvm.h
> +++ b/include/linux/lightnvm.h
> @@ -308,7 +308,6 @@ struct nvm_dev {
>  	struct nvm_dev_ops *ops;
>  
>  	struct list_head devices;
> -	struct list_head online_targets;
>  
>  	/* Media manager */
>  	struct nvmm_type *mt;
> 

Thanks. Applied for 4.7.