[PATCH] fs/partitions/check.c: add_partition() warning fixes (take 2)

[PATCH] fs/partitions/check.c: add_partition() warning fixes (take 2)

[Eugene Teo]

This patch fixes these warnings:

fs/partitions/check.c: In function 'add_partition':
fs/partitions/check.c:391: warning: ignoring return value of 'kobject_add',
	declared with attribute warn_unused_result
fs/partitions/check.c:394: warning: ignoring return value of
	'sysfs_create_link', declared with attribute warn_unused_result
fs/partitions/check.c:401: warning: ignoring return value of
	'sysfs_create_file', declared with attribute warn_unused_result

Signed-off-by: Eugene Teo <eugeneteo@kernel.sg>
---
 fs/partitions/check.c |   23 ++++++++++++++++++++---
 1 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 783c57e..57cc590 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -371,6 +371,7 @@ void delete_partition(struct gendisk *disk, int part)
 void add_partition(struct gendisk *disk, int part, sector_t start, sector_t len, int flags)
 {
 	struct hd_struct *p;
+	int err;
 
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p)
@@ -388,20 +389,36 @@ void add_partition(struct gendisk *disk, int part, sector_t start, sector_t len,
 	p->kobj.parent = &disk->kobj;
 	p->kobj.ktype = &ktype_part;
 	kobject_init(&p->kobj);
-	kobject_add(&p->kobj);
+	err = kobject_add(&p->kobj);
+	if (err)
+		goto err_out;
 	if (!disk->part_uevent_suppress)
 		kobject_uevent(&p->kobj, KOBJ_ADD);
-	sysfs_create_link(&p->kobj, &block_subsys.kobj, "subsystem");
+	err = sysfs_create_link(&p->kobj, &block_subsys.kobj, "subsystem");
+	if (err)
+		goto err_out_del_kobj;
 	if (flags & ADDPART_FLAG_WHOLEDISK) {
 		static struct attribute addpartattr = {
 			.name = "whole_disk",
 			.mode = S_IRUSR | S_IRGRP | S_IROTH,
 		};
 
-		sysfs_create_file(&p->kobj, &addpartattr);
+		err = sysfs_create_file(&p->kobj, &addpartattr);
+		if (err)
+			goto err_out_del_link;
 	}
 	partition_sysfs_add_subdir(p);
 	disk->part[part-1] = p;
+	return;
+
+err_out_del_link:
+	sysfs_remove_link(&p->kobj, "subsystem");
+err_out_del_kobj:
+	if (!disk->part_uevent_suppress)
+		kobject_uevent(&p->kobj, KOBJ_REMOVE);
+	kobject_put(&p->kobj);
+err_out:
+	kfree(p);
 }
 
 static char *make_block_name(struct gendisk *disk)

Re: [PATCH] fs/partitions/check.c: add_partition() warning fixes (take 2)

[Cornelia Huck]

On Mon, 30 Jul 2007 17:47:55 +0800,
Eugene Teo <eugeneteo@kernel.sg> wrote:

> +err_out_del_link:
> +	sysfs_remove_link(&p->kobj, "subsystem");
> +err_out_del_kobj:
> +	if (!disk->part_uevent_suppress)
> +		kobject_uevent(&p->kobj, KOBJ_REMOVE);
> +	kobject_put(&p->kobj);
> +err_out:
> +	kfree(p);
>  }

No, this is wrong. You need to move the put behind err_out and remove
the kfree. (The release function will take care of p.)

Re: [PATCH] fs/partitions/check.c: add_partition() warning fixes (take 2)

[Eugene Teo]

Cornelia Huck wrote:
> On Mon, 30 Jul 2007 17:47:55 +0800,
> Eugene Teo <eugeneteo@kernel.sg> wrote:
> 
>> +err_out_del_link:
>> +	sysfs_remove_link(&p->kobj, "subsystem");
>> +err_out_del_kobj:
>> +	if (!disk->part_uevent_suppress)
>> +		kobject_uevent(&p->kobj, KOBJ_REMOVE);
>> +	kobject_put(&p->kobj);
>> +err_out:
>> +	kfree(p);
>>  }
> 
> No, this is wrong. You need to move the put behind err_out and remove
> the kfree. (The release function will take care of p.)

503 void kobject_put(struct kobject * kobj)
504 {
505         if (kobj)
506                 kref_put(&kobj->kref, kobject_release);
[...]
 52 int kref_put(struct kref *kref, void (*release)(struct kref *kref))
 53 {
[...]
 57         if (atomic_dec_and_test(&kref->refcount)) {
 58                 release(kref);
 59                 return 1;

Nod, thanks for your guidance.

Eugene