bcachefs: chardev: make bch_chardev_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the bch_chardev_class structure to be declared at build
time placing it into read-only memory, instead of having to be dynamically
allocated at boot time. Also, correctly clean up after failing paths in
bch2_chardev_init().

Cc: Hongbo Li <lihongbo22@huawei.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/chardev.c b/fs/bcachefs/chardev.c
index 4d14f19f51850e9d024ee69bd1f68d5a3743a2b0..dbcd433db0049862c16abc7d6ea3ec084df3d689 100644 (file)
--- a/fs/bcachefs/chardev.c
+++ b/fs/bcachefs/chardev.c
@@ -961,7 +961,9 @@ static const struct file_operations bch_chardev_fops = {
 };
 
 static int bch_chardev_major;
-static struct class *bch_chardev_class;
+static const struct class bch_chardev_class = {
+       .name = "bcachefs",
+};
 static struct device *bch_chardev;
 
 void bch2_fs_chardev_exit(struct bch_fs *c)
@@ -978,7 +980,7 @@ int bch2_fs_chardev_init(struct bch_fs *c)
        if (c->minor < 0)
                return c->minor;
 
-       c->chardev = device_create(bch_chardev_class, NULL,
+       c->chardev = device_create(&bch_chardev_class, NULL,
                                   MKDEV(bch_chardev_major, c->minor), c,
                                   "bcachefs%u-ctl", c->minor);
        if (IS_ERR(c->chardev))
@@ -989,32 +991,39 @@ int bch2_fs_chardev_init(struct bch_fs *c)
 
 void bch2_chardev_exit(void)
 {
-       if (!IS_ERR_OR_NULL(bch_chardev_class))
-               device_destroy(bch_chardev_class,
-                              MKDEV(bch_chardev_major, U8_MAX));
-       if (!IS_ERR_OR_NULL(bch_chardev_class))
-               class_destroy(bch_chardev_class);
+       device_destroy(&bch_chardev_class, MKDEV(bch_chardev_major, U8_MAX));
+       class_unregister(&bch_chardev_class);
        if (bch_chardev_major > 0)
                unregister_chrdev(bch_chardev_major, "bcachefs");
 }
 
 int __init bch2_chardev_init(void)
 {
+       int ret;
+
        bch_chardev_major = register_chrdev(0, "bcachefs-ctl", &bch_chardev_fops);
        if (bch_chardev_major < 0)
                return bch_chardev_major;
 
-       bch_chardev_class = class_create("bcachefs");
-       if (IS_ERR(bch_chardev_class))
-               return PTR_ERR(bch_chardev_class);
+       ret = class_register(&bch_chardev_class);
+       if (ret)
+               goto major_out;
 
-       bch_chardev = device_create(bch_chardev_class, NULL,
+       bch_chardev = device_create(&bch_chardev_class, NULL,
                                    MKDEV(bch_chardev_major, U8_MAX),
                                    NULL, "bcachefs-ctl");
-       if (IS_ERR(bch_chardev))
-               return PTR_ERR(bch_chardev);
+       if (IS_ERR(bch_chardev)) {
+               ret = PTR_ERR(bch_chardev);
+               goto class_out;
+       }
 
        return 0;
+
+class_out:
+       class_unregister(&bch_chardev_class);
+major_out:
+       unregister_chrdev(bch_chardev_major, "bcachefs-ctl");
+       return ret;
 }
 
 #endif /* NO_BCACHEFS_CHARDEV */