linux-kernel - Re: [PATCH 2/2] lightnvm: hold nvm_lock until finish the target creation

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Message-ID: <573DB4B1.1050501@lightnvm.io>
Date:	Thu, 19 May 2016 14:42:25 +0200
From:	Matias Bjørling <mb@...htnvm.io>
To:	Wenwei Tao <wwtao0320@....com>
Cc:	linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
	ww.tao0320@...il.com
Subject: Re: [PATCH 2/2] lightnvm: hold nvm_lock until finish the target
 creation

On 05/19/2016 08:38 AM, Wenwei Tao wrote:
> From: Wenwei Tao <ww.tao0320@...il.com>
>
> When create a target, we check whether the target is
> already exist first. If the answer is no, we release
> the lock and continue the creation. This cannot prevent
> concurrent creation of the same target, so hold the lock
> until finish the target creation.
>
> Signed-off-by: Wenwei Tao <ww.tao0320@...il.com>
> ---
>   drivers/lightnvm/core.c | 18 +++++++++---------
>   1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 160c1a6..a622081 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -791,6 +791,7 @@ static int nvm_create_target(struct nvm_dev *dev,
>   	struct nvm_tgt_type *tt;
>   	struct nvm_target *t;
>   	void *targetdata;
> +	int ret = -ENOMEM;
>
>   	if (!dev->mt) {
>   		pr_info("nvm: device has no media manager registered.\n");
> @@ -801,21 +802,20 @@ static int nvm_create_target(struct nvm_dev *dev,
>   	tt = nvm_find_target_type(create->tgttype);
>   	if (!tt) {
>   		pr_err("nvm: target type %s not found\n", create->tgttype);
> -		up_write(&nvm_lock);
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto err_unlock;
>   	}
>
>   	t = nvm_find_target(create->tgtname);
>   	if (t) {
>   		pr_err("nvm: target name already exists.\n");
> -		up_write(&nvm_lock);
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto err_unlock;
>   	}
> -	up_write(&nvm_lock);
>
>   	t = kmalloc(sizeof(struct nvm_target), GFP_KERNEL);
>   	if (!t)
> -		return -ENOMEM;
> +		goto err_unlock;
>
>   	tqueue = blk_alloc_queue_node(GFP_KERNEL, dev->q->node);
>   	if (!tqueue)
> @@ -848,8 +848,6 @@ static int nvm_create_target(struct nvm_dev *dev,
>   	t->type = tt;
>   	t->disk = tdisk;
>   	t->dev = dev;
> -
> -	down_write(&nvm_lock);
>   	list_add_tail(&t->list, &nvm_targets);
>   	up_write(&nvm_lock);
>
> @@ -860,7 +858,9 @@ err_queue:
>   	blk_cleanup_queue(tqueue);
>   err_t:
>   	kfree(t);
> -	return -ENOMEM;
> +err_unlock:
> +	up_write(&nvm_lock);
> +	return ret;
>   }
>
>   static int __nvm_configure_create(struct nvm_ioctl_create *create)
>

Thanks. There is a couple of patches in the for-4.8/core that moves this 
logic to the gennvm media manager. Could you rebase this on top?