Unverified Commit 3685744a authored by chen zhang's avatar chen zhang Committed by Christian Brauner
Browse files

chardev: Switch to guard(mutex) and __free(kfree) 



Instead of using the 'goto label; mutex_unlock()' pattern use
'guard(mutex)' which will release the mutex when it goes out of scope.
Use the __free(kfree) cleanup to replace instances of manually
calling kfree(). Also make some code path simplifications that this
allows.

Signed-off-by: default avatarchen zhang <chenzhang@kylinos.cn>
Link: https://patch.msgid.link/20251215111500.159243-1-chenzhang@kylinos.cn


Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 3f320e5c

fs/char_dev.c

+7 −10
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/kdev_t.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/cleanup.h>



#include <linux/major.h>

#include <linux/errno.h>
@@ -97,7 +98,8 @@ static struct char_device_struct * 
__register_chrdev_region(unsigned int major, unsigned int baseminor,

			   int minorct, const char *name)

{

	struct char_device_struct *cd, *curr, *prev = NULL;

	struct char_device_struct *cd __free(kfree) = NULL;

	struct char_device_struct *curr, *prev = NULL;

	int ret;

	int i;
@@ -117,14 +119,14 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor, 
	if (cd == NULL)

		return ERR_PTR(-ENOMEM);



	mutex_lock(&chrdevs_lock);

	guard(mutex)(&chrdevs_lock);



	if (major == 0) {

		ret = find_dynamic_major();

		if (ret < 0) {

			pr_err("CHRDEV \"%s\" dynamic allocation region is full\n",

			       name);

			goto out;

			return ERR_PTR(ret);

		}

		major = ret;

	}
@@ -144,7 +146,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor, 
		if (curr->baseminor >= baseminor + minorct)

			break;



		goto out;

		return ERR_PTR(ret);

	}



	cd->major = major;
@@ -160,12 +162,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor, 
		prev->next = cd;

	}



	mutex_unlock(&chrdevs_lock);

	return cd;

out:

	mutex_unlock(&chrdevs_lock);

	kfree(cd);

	return ERR_PTR(ret);

	return_ptr(cd);

}



static struct char_device_struct *