[PATCH v2] dm-lc.c: Audit return values of functions invoked in module init routine

[PATCH v2] dm-lc.c: Audit return values of functions invoked in module init routine

[Kumar Amit Mehta]

Add missing checks for values returned by various functions for
graceful exit in the event of failure.

Signed-off-by: Kumar Amit Mehta <gmate.amit@gmail.com>
---
 Driver/dm-lc.c | 61 +++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 43 insertions(+), 18 deletions(-)

diff --git a/Driver/dm-lc.c b/Driver/dm-lc.c
index 6644115..4a65042 100644
--- a/Driver/dm-lc.c
+++ b/Driver/dm-lc.c
@@ -2924,14 +2924,7 @@ static struct target_type lc_mgr_target = {
 
 static int __init lc_module_init(void)
 {
-	int r;
-
-	safe_io_wq = alloc_workqueue("safeiowq",
-				     WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
-	if (!safe_io_wq)
-		return -ENOMEM;
-
-	lc_io_client = dm_io_client_create();
+	int r = -ENOMEM;
 
 	r = dm_register_target(&lc_target);
 	if (r < 0) {
@@ -2942,18 +2935,9 @@ static int __init lc_module_init(void)
 	r = dm_register_target(&lc_mgr_target);
 	if (r < 0) {
 		DMERR("register lc-mgr failed %d", r);
-		return r;
+		goto bad_register_mgr_target;
 	}
 
-	cache_id_ptr = 0;
-
-	size_t i;
-	for (i = 0; i < LC_NR_SLOTS; i++)
-		lc_devices[i] = NULL;
-
-	for (i = 0; i < LC_NR_SLOTS; i++)
-		lc_caches[i] = NULL;
-
 	/*
 	 * /sys/module/dm_lc/devices
 	 *                  /caches
@@ -2961,10 +2945,51 @@ static int __init lc_module_init(void)
 
 	struct module *mod = THIS_MODULE;
 	struct kobject *lc_kobj = &(mod->mkobj.kobj);
+
 	devices_kobj = kobject_create_and_add("devices", lc_kobj);
+	if (!devices_kobj)
+		goto bad_kobj_devices;
+
 	caches_kobj = kobject_create_and_add("caches", lc_kobj);
+	if (!caches_kobj)
+		goto bad_kobj_caches;
+
+	safe_io_wq = alloc_workqueue("safeiowq",
+				     WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
+	if (!safe_io_wq) {
+		DMERR("failed to create workqueue safeiowq");
+		goto bad_wq;
+	}
+
+	lc_io_client = dm_io_client_create();
+	if (IS_ERR(lc_io_client)) {
+		r = PTR_ERR(lc_io_client);
+		goto bad_io_client;
+	}
+
+	cache_id_ptr = 0;
+
+	size_t i;
+	for (i = 0; i < LC_NR_SLOTS; i++)
+		lc_devices[i] = NULL;
+
+	for (i = 0; i < LC_NR_SLOTS; i++)
+		lc_caches[i] = NULL;
 
 	return 0;
+
+bad_io_client:
+	destroy_workqueue(safe_io_wq);
+bad_wq:
+	kobject_put(caches_kobj);
+bad_kobj_caches:
+	kobject_put(devices_kobj);
+bad_kobj_devices:
+	dm_unregister_target(&lc_mgr_target);
+bad_register_mgr_target:
+	dm_unregister_target(&lc_target);
+
+	return ERR_PTR(r);
 }
 
 static void __exit lc_module_exit(void)
-- 
1.8.3.1

Re: [PATCH v2] dm-lc.c: Audit return values of functions invoked in module init routine

[Akira Hayakawa]

Thanks, Kumar.
The patch is fine now, applied.

Akira

On 7/31/13 6:09 PM, Kumar Amit Mehta wrote:
> Add missing checks for values returned by various functions for
> graceful exit in the event of failure.
> 
> Signed-off-by: Kumar Amit Mehta <gmate.amit@gmail.com>
> ---
>  Driver/dm-lc.c | 61 +++++++++++++++++++++++++++++++++++++++++-----------------
>  1 file changed, 43 insertions(+), 18 deletions(-)
> 
> diff --git a/Driver/dm-lc.c b/Driver/dm-lc.c
> index 6644115..4a65042 100644
> --- a/Driver/dm-lc.c
> +++ b/Driver/dm-lc.c
> @@ -2924,14 +2924,7 @@ static struct target_type lc_mgr_target = {
>  
>  static int __init lc_module_init(void)
>  {
> -	int r;
> -
> -	safe_io_wq = alloc_workqueue("safeiowq",
> -				     WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
> -	if (!safe_io_wq)
> -		return -ENOMEM;
> -
> -	lc_io_client = dm_io_client_create();
> +	int r = -ENOMEM;
>  
>  	r = dm_register_target(&lc_target);
>  	if (r < 0) {
> @@ -2942,18 +2935,9 @@ static int __init lc_module_init(void)
>  	r = dm_register_target(&lc_mgr_target);
>  	if (r < 0) {
>  		DMERR("register lc-mgr failed %d", r);
> -		return r;
> +		goto bad_register_mgr_target;
>  	}
>  
> -	cache_id_ptr = 0;
> -
> -	size_t i;
> -	for (i = 0; i < LC_NR_SLOTS; i++)
> -		lc_devices[i] = NULL;
> -
> -	for (i = 0; i < LC_NR_SLOTS; i++)
> -		lc_caches[i] = NULL;
> -
>  	/*
>  	 * /sys/module/dm_lc/devices
>  	 *                  /caches
> @@ -2961,10 +2945,51 @@ static int __init lc_module_init(void)
>  
>  	struct module *mod = THIS_MODULE;
>  	struct kobject *lc_kobj = &(mod->mkobj.kobj);
> +
>  	devices_kobj = kobject_create_and_add("devices", lc_kobj);
> +	if (!devices_kobj)
> +		goto bad_kobj_devices;
> +
>  	caches_kobj = kobject_create_and_add("caches", lc_kobj);
> +	if (!caches_kobj)
> +		goto bad_kobj_caches;
> +
> +	safe_io_wq = alloc_workqueue("safeiowq",
> +				     WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
> +	if (!safe_io_wq) {
> +		DMERR("failed to create workqueue safeiowq");
> +		goto bad_wq;
> +	}
> +
> +	lc_io_client = dm_io_client_create();
> +	if (IS_ERR(lc_io_client)) {
> +		r = PTR_ERR(lc_io_client);
> +		goto bad_io_client;
> +	}
> +
> +	cache_id_ptr = 0;
> +
> +	size_t i;
> +	for (i = 0; i < LC_NR_SLOTS; i++)
> +		lc_devices[i] = NULL;
> +
> +	for (i = 0; i < LC_NR_SLOTS; i++)
> +		lc_caches[i] = NULL;
>  
>  	return 0;
> +
> +bad_io_client:
> +	destroy_workqueue(safe_io_wq);
> +bad_wq:
> +	kobject_put(caches_kobj);
> +bad_kobj_caches:
> +	kobject_put(devices_kobj);
> +bad_kobj_devices:
> +	dm_unregister_target(&lc_mgr_target);
> +bad_register_mgr_target:
> +	dm_unregister_target(&lc_target);
> +
> +	return ERR_PTR(r);
>  }
>  
>  static void __exit lc_module_exit(void)
>