[v2,1/3] lightnvm: missing nvm_lock acquire
diff mbox

Message ID 1448597384-27976-2-git-send-email-ww.tao0320@gmail.com
State New
Headers show

Commit Message

Wenwei Tao Nov. 27, 2015, 4:09 a.m. UTC
To avoid race conditions, traverse dev, media manager,
and targeet lists and also register, unregister entries
to/from them, should be always under the nvm_lock control.

Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
---
 drivers/lightnvm/core.c | 73 +++++++++++++++++++++++++------------------------
 1 file changed, 38 insertions(+), 35 deletions(-)

Comments

Matias Bjorling Nov. 27, 2015, 8:31 a.m. UTC | #1
On 11/27/2015 05:09 AM, Wenwei Tao wrote:
> To avoid race conditions, traverse dev, media manager,
> and targeet lists and also register, unregister entries
> to/from them, should be always under the nvm_lock control.
>
> Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
> ---
>   drivers/lightnvm/core.c | 73 +++++++++++++++++++++++++------------------------
>   1 file changed, 38 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 5178645..071a3e4 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -123,6 +123,24 @@ void nvm_unregister_mgr(struct nvmm_type *mt)
>   }
>   EXPORT_SYMBOL(nvm_unregister_mgr);
>
> +/* register with device with a supported manager */
> +static int register_mgr(struct nvm_dev *dev)
> +{
> +	struct nvmm_type *mt;
> +	int ret = 0;
> +
> +	list_for_each_entry(mt, &nvm_mgrs, list) {
> +		ret = mt->register_mgr(dev);
> +		if (ret > 0) {
> +			dev->mt = mt;
> +			break; /* successfully initialized */
> +		}
> +	}
> +	if (!ret)
> +		pr_info("nvm: no compatible nvm manager found.\n");
> +	return ret;
> +}
> +
>   static struct nvm_dev *nvm_find_nvm_dev(const char *name)
>   {
>   	struct nvm_dev *dev;
> @@ -221,7 +239,6 @@ static void nvm_free(struct nvm_dev *dev)
>
>   static int nvm_init(struct nvm_dev *dev)
>   {
> -	struct nvmm_type *mt;
>   	int ret = -EINVAL;
>
>   	if (!dev->q || !dev->ops)
> @@ -251,22 +268,13 @@ static int nvm_init(struct nvm_dev *dev)
>   		pr_err("nvm: could not initialize core structures.\n");
>   		goto err;
>   	}
> -
> -	/* register with device with a supported manager */
> -	list_for_each_entry(mt, &nvm_mgrs, list) {
> -		ret = mt->register_mgr(dev);
> -		if (ret < 0)
> -			goto err; /* initialization failed */
> -		if (ret > 0) {
> -			dev->mt = mt;
> -			break; /* successfully initialized */
> -		}
> -	}
> -
> -	if (!ret) {
> -		pr_info("nvm: no compatible manager found.\n");
> +	down_write(&nvm_lock);
> +	ret = register_mgr(dev);
> +	up_write(&nvm_lock);
> +	if (ret < 0)
> +		goto err;
> +	if (!ret)
>   		return 0;
> -	}
>
>   	pr_info("nvm: registered %s [%u/%u/%u/%u/%u/%u]\n",
>   			dev->name, dev->sec_per_pg, dev->nr_planes,
> @@ -335,18 +343,18 @@ EXPORT_SYMBOL(nvm_register);
>
>   void nvm_unregister(char *disk_name)
>   {
> +	down_write(&nvm_lock);
>   	struct nvm_dev *dev = nvm_find_nvm_dev(disk_name);
>
>   	if (!dev) {
>   		pr_err("nvm: could not find device %s to unregister\n",
>   								disk_name);
> +		up_write(&nvm_lock);
>   		return;
>   	}
>
> -	down_write(&nvm_lock);
>   	list_del(&dev->devices);
>   	up_write(&nvm_lock);
> -
>   	nvm_exit(dev);
>   	kfree(dev);
>   }
> @@ -361,38 +369,30 @@ static int nvm_create_target(struct nvm_dev *dev,
>   {
>   	struct nvm_ioctl_create_simple *s = &create->conf.s;
>   	struct request_queue *tqueue;
> -	struct nvmm_type *mt;
>   	struct gendisk *tdisk;
>   	struct nvm_tgt_type *tt;
>   	struct nvm_target *t;
>   	void *targetdata;
>   	int ret = 0;
>
> +	down_write(&nvm_lock);
>   	if (!dev->mt) {
> -		/* register with device with a supported NVM manager */
> -		list_for_each_entry(mt, &nvm_mgrs, list) {
> -			ret = mt->register_mgr(dev);
> -			if (ret < 0)
> -				return ret; /* initialization failed */
> -			if (ret > 0) {
> -				dev->mt = mt;
> -				break; /* successfully initialized */
> -			}
> -		}
> -
> -		if (!ret) {
> -			pr_info("nvm: no compatible nvm manager found.\n");
> -			return -ENODEV;
> +		ret = register_mgr(dev);
> +		if (!ret)
> +			ret = -ENODEV;
> +		if (ret < 0) {
> +			up_write(&nvm_lock);
> +			return ret;
>   		}
>   	}
>
>   	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;
>   	}
>
> -	down_write(&nvm_lock);
>   	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");
> @@ -475,8 +475,9 @@ static int __nvm_configure_create(struct nvm_ioctl_create *create)
>   {
>   	struct nvm_dev *dev;
>   	struct nvm_ioctl_create_simple *s;
> -
> +	down_write(&nvm_lock);
>   	dev = nvm_find_nvm_dev(create->dev);
> +	up_write(&nvm_lock);
>   	if (!dev) {
>   		pr_err("nvm: device not found\n");
>   		return -EINVAL;
> @@ -535,7 +536,9 @@ static int nvm_configure_show(const char *val)
>   		return -EINVAL;
>   	}
>
> +	down_write(&nvm_lock);
>   	dev = nvm_find_nvm_dev(devname);
> +	up_write(&nvm_lock);
>   	if (!dev) {
>   		pr_err("nvm: device not found\n");
>   		return -EINVAL;
>

Thanks Wei. I applied the previous version of the patch.

You can see the patches I have queued for upstream in the for-next at 
https://github.com/OpenChannelSSD/linux/commits/for-next
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Wenwei Tao Nov. 27, 2015, 12:04 p.m. UTC | #2
Hi Matias
Previous version patch miss acquire lock before find supported manager
in nvm_init().
And find supported manager code is duplicated in nvm_init() and
nvm_create_target(), we may move it into a function to make the code
more clean.
And find supported manager may blocked while holding the lock, this is
not good.

2015-11-27 16:31 GMT+08:00 Matias Bjørling <m@bjorling.me>:
> On 11/27/2015 05:09 AM, Wenwei Tao wrote:
>>
>> To avoid race conditions, traverse dev, media manager,
>> and targeet lists and also register, unregister entries
>> to/from them, should be always under the nvm_lock control.
>>
>> Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
>> ---
>>   drivers/lightnvm/core.c | 73
>> +++++++++++++++++++++++++------------------------
>>   1 file changed, 38 insertions(+), 35 deletions(-)
>>
>> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
>> index 5178645..071a3e4 100644
>> --- a/drivers/lightnvm/core.c
>> +++ b/drivers/lightnvm/core.c
>> @@ -123,6 +123,24 @@ void nvm_unregister_mgr(struct nvmm_type *mt)
>>   }
>>   EXPORT_SYMBOL(nvm_unregister_mgr);
>>
>> +/* register with device with a supported manager */
>> +static int register_mgr(struct nvm_dev *dev)
>> +{
>> +       struct nvmm_type *mt;
>> +       int ret = 0;
>> +
>> +       list_for_each_entry(mt, &nvm_mgrs, list) {
>> +               ret = mt->register_mgr(dev);
>> +               if (ret > 0) {
>> +                       dev->mt = mt;
>> +                       break; /* successfully initialized */
>> +               }
>> +       }
>> +       if (!ret)
>> +               pr_info("nvm: no compatible nvm manager found.\n");
>> +       return ret;
>> +}
>> +
>>   static struct nvm_dev *nvm_find_nvm_dev(const char *name)
>>   {
>>         struct nvm_dev *dev;
>> @@ -221,7 +239,6 @@ static void nvm_free(struct nvm_dev *dev)
>>
>>   static int nvm_init(struct nvm_dev *dev)
>>   {
>> -       struct nvmm_type *mt;
>>         int ret = -EINVAL;
>>
>>         if (!dev->q || !dev->ops)
>> @@ -251,22 +268,13 @@ static int nvm_init(struct nvm_dev *dev)
>>                 pr_err("nvm: could not initialize core structures.\n");
>>                 goto err;
>>         }
>> -
>> -       /* register with device with a supported manager */
>> -       list_for_each_entry(mt, &nvm_mgrs, list) {
>> -               ret = mt->register_mgr(dev);
>> -               if (ret < 0)
>> -                       goto err; /* initialization failed */
>> -               if (ret > 0) {
>> -                       dev->mt = mt;
>> -                       break; /* successfully initialized */
>> -               }
>> -       }
>> -
>> -       if (!ret) {
>> -               pr_info("nvm: no compatible manager found.\n");
>> +       down_write(&nvm_lock);
>> +       ret = register_mgr(dev);
>> +       up_write(&nvm_lock);
>> +       if (ret < 0)
>> +               goto err;
>> +       if (!ret)
>>                 return 0;
>> -       }
>>
>>         pr_info("nvm: registered %s [%u/%u/%u/%u/%u/%u]\n",
>>                         dev->name, dev->sec_per_pg, dev->nr_planes,
>> @@ -335,18 +343,18 @@ EXPORT_SYMBOL(nvm_register);
>>
>>   void nvm_unregister(char *disk_name)
>>   {
>> +       down_write(&nvm_lock);
>>         struct nvm_dev *dev = nvm_find_nvm_dev(disk_name);
>>
>>         if (!dev) {
>>                 pr_err("nvm: could not find device %s to unregister\n",
>>
>> disk_name);
>> +               up_write(&nvm_lock);
>>                 return;
>>         }
>>
>> -       down_write(&nvm_lock);
>>         list_del(&dev->devices);
>>         up_write(&nvm_lock);
>> -
>>         nvm_exit(dev);
>>         kfree(dev);
>>   }
>> @@ -361,38 +369,30 @@ static int nvm_create_target(struct nvm_dev *dev,
>>   {
>>         struct nvm_ioctl_create_simple *s = &create->conf.s;
>>         struct request_queue *tqueue;
>> -       struct nvmm_type *mt;
>>         struct gendisk *tdisk;
>>         struct nvm_tgt_type *tt;
>>         struct nvm_target *t;
>>         void *targetdata;
>>         int ret = 0;
>>
>> +       down_write(&nvm_lock);
>>         if (!dev->mt) {
>> -               /* register with device with a supported NVM manager */
>> -               list_for_each_entry(mt, &nvm_mgrs, list) {
>> -                       ret = mt->register_mgr(dev);
>> -                       if (ret < 0)
>> -                               return ret; /* initialization failed */
>> -                       if (ret > 0) {
>> -                               dev->mt = mt;
>> -                               break; /* successfully initialized */
>> -                       }
>> -               }
>> -
>> -               if (!ret) {
>> -                       pr_info("nvm: no compatible nvm manager
>> found.\n");
>> -                       return -ENODEV;
>> +               ret = register_mgr(dev);
>> +               if (!ret)
>> +                       ret = -ENODEV;
>> +               if (ret < 0) {
>> +                       up_write(&nvm_lock);
>> +                       return ret;
>>                 }
>>         }
>>
>>         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;
>>         }
>>
>> -       down_write(&nvm_lock);
>>         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");
>> @@ -475,8 +475,9 @@ static int __nvm_configure_create(struct
>> nvm_ioctl_create *create)
>>   {
>>         struct nvm_dev *dev;
>>         struct nvm_ioctl_create_simple *s;
>> -
>> +       down_write(&nvm_lock);
>>         dev = nvm_find_nvm_dev(create->dev);
>> +       up_write(&nvm_lock);
>>         if (!dev) {
>>                 pr_err("nvm: device not found\n");
>>                 return -EINVAL;
>> @@ -535,7 +536,9 @@ static int nvm_configure_show(const char *val)
>>                 return -EINVAL;
>>         }
>>
>> +       down_write(&nvm_lock);
>>         dev = nvm_find_nvm_dev(devname);
>> +       up_write(&nvm_lock);
>>         if (!dev) {
>>                 pr_err("nvm: device not found\n");
>>                 return -EINVAL;
>>
>
> Thanks Wei. I applied the previous version of the patch.
>
> You can see the patches I have queued for upstream in the for-next at
> https://github.com/OpenChannelSSD/linux/commits/for-next
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Matias Bjorling Nov. 27, 2015, 7:41 p.m. UTC | #3
On 11/27/2015 01:04 PM, Wenwei Tao wrote:
> Hi Matias
> Previous version patch miss acquire lock before find supported manager
> in nvm_init().
> And find supported manager code is duplicated in nvm_init() and
> nvm_create_target(), we may move it into a function to make the code
> more clean.
> And find supported manager may blocked while holding the lock, this is
> not good.
>

Ok, thanks. I'll pick this one up instead then.

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Wenwei Tao Nov. 28, 2015, 1:44 a.m. UTC | #4
Hi Matiasl
Just to let you know this patch and previous version both cannot
address 'register device with supported manager may blocked while
holding the lock' issue.

2015-11-28 3:41 GMT+08:00 Matias Bjørling <m@bjorling.me>:
> On 11/27/2015 01:04 PM, Wenwei Tao wrote:
>>
>> Hi Matias
>> Previous version patch miss acquire lock before find supported manager
>> in nvm_init().
>> And find supported manager code is duplicated in nvm_init() and
>> nvm_create_target(), we may move it into a function to make the code
>> more clean.
>> And find supported manager may blocked while holding the lock, this is
>> not good.
>>
>
> Ok, thanks. I'll pick this one up instead then.
>
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Patch
diff mbox

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 5178645..071a3e4 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -123,6 +123,24 @@  void nvm_unregister_mgr(struct nvmm_type *mt)
 }
 EXPORT_SYMBOL(nvm_unregister_mgr);
 
+/* register with device with a supported manager */
+static int register_mgr(struct nvm_dev *dev)
+{
+	struct nvmm_type *mt;
+	int ret = 0;
+
+	list_for_each_entry(mt, &nvm_mgrs, list) {
+		ret = mt->register_mgr(dev);
+		if (ret > 0) {
+			dev->mt = mt;
+			break; /* successfully initialized */
+		}
+	}
+	if (!ret)
+		pr_info("nvm: no compatible nvm manager found.\n");
+	return ret;
+}
+
 static struct nvm_dev *nvm_find_nvm_dev(const char *name)
 {
 	struct nvm_dev *dev;
@@ -221,7 +239,6 @@  static void nvm_free(struct nvm_dev *dev)
 
 static int nvm_init(struct nvm_dev *dev)
 {
-	struct nvmm_type *mt;
 	int ret = -EINVAL;
 
 	if (!dev->q || !dev->ops)
@@ -251,22 +268,13 @@  static int nvm_init(struct nvm_dev *dev)
 		pr_err("nvm: could not initialize core structures.\n");
 		goto err;
 	}
-
-	/* register with device with a supported manager */
-	list_for_each_entry(mt, &nvm_mgrs, list) {
-		ret = mt->register_mgr(dev);
-		if (ret < 0)
-			goto err; /* initialization failed */
-		if (ret > 0) {
-			dev->mt = mt;
-			break; /* successfully initialized */
-		}
-	}
-
-	if (!ret) {
-		pr_info("nvm: no compatible manager found.\n");
+	down_write(&nvm_lock);
+	ret = register_mgr(dev);
+	up_write(&nvm_lock);
+	if (ret < 0)
+		goto err;
+	if (!ret)
 		return 0;
-	}
 
 	pr_info("nvm: registered %s [%u/%u/%u/%u/%u/%u]\n",
 			dev->name, dev->sec_per_pg, dev->nr_planes,
@@ -335,18 +343,18 @@  EXPORT_SYMBOL(nvm_register);
 
 void nvm_unregister(char *disk_name)
 {
+	down_write(&nvm_lock);
 	struct nvm_dev *dev = nvm_find_nvm_dev(disk_name);
 
 	if (!dev) {
 		pr_err("nvm: could not find device %s to unregister\n",
 								disk_name);
+		up_write(&nvm_lock);
 		return;
 	}
 
-	down_write(&nvm_lock);
 	list_del(&dev->devices);
 	up_write(&nvm_lock);
-
 	nvm_exit(dev);
 	kfree(dev);
 }
@@ -361,38 +369,30 @@  static int nvm_create_target(struct nvm_dev *dev,
 {
 	struct nvm_ioctl_create_simple *s = &create->conf.s;
 	struct request_queue *tqueue;
-	struct nvmm_type *mt;
 	struct gendisk *tdisk;
 	struct nvm_tgt_type *tt;
 	struct nvm_target *t;
 	void *targetdata;
 	int ret = 0;
 
+	down_write(&nvm_lock);
 	if (!dev->mt) {
-		/* register with device with a supported NVM manager */
-		list_for_each_entry(mt, &nvm_mgrs, list) {
-			ret = mt->register_mgr(dev);
-			if (ret < 0)
-				return ret; /* initialization failed */
-			if (ret > 0) {
-				dev->mt = mt;
-				break; /* successfully initialized */
-			}
-		}
-
-		if (!ret) {
-			pr_info("nvm: no compatible nvm manager found.\n");
-			return -ENODEV;
+		ret = register_mgr(dev);
+		if (!ret)
+			ret = -ENODEV;
+		if (ret < 0) {
+			up_write(&nvm_lock);
+			return ret;
 		}
 	}
 
 	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;
 	}
 
-	down_write(&nvm_lock);
 	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");
@@ -475,8 +475,9 @@  static int __nvm_configure_create(struct nvm_ioctl_create *create)
 {
 	struct nvm_dev *dev;
 	struct nvm_ioctl_create_simple *s;
-
+	down_write(&nvm_lock);
 	dev = nvm_find_nvm_dev(create->dev);
+	up_write(&nvm_lock);
 	if (!dev) {
 		pr_err("nvm: device not found\n");
 		return -EINVAL;
@@ -535,7 +536,9 @@  static int nvm_configure_show(const char *val)
 		return -EINVAL;
 	}
 
+	down_write(&nvm_lock);
 	dev = nvm_find_nvm_dev(devname);
+	up_write(&nvm_lock);
 	if (!dev) {
 		pr_err("nvm: device not found\n");
 		return -EINVAL;