ublk: make ublk_chr_class a static const structure

Now that the driver core allows for struct class to be in read-only
memory, move the ublk_chr_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230620180129.645646-7-gregkh@linuxfoundation.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 9fdc4c7f908dd09467e25348c6442cb236535661..6287f13d16200eeeaa5772318fd076223268f02a 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -189,7 +189,9 @@ static inline void __ublk_complete_rq(struct request *req);
 static void ublk_complete_rq(struct kref *ref);
 
 static dev_t ublk_chr_devt;
-static struct class *ublk_chr_class;
+static const struct class ublk_chr_class = {
+       .name = "ublk-char",
+};
 
 static DEFINE_IDR(ublk_index_idr);
 static DEFINE_SPINLOCK(ublk_idr_lock);
@@ -1755,7 +1757,7 @@ static int ublk_add_chdev(struct ublk_device *ub)
 
        dev->parent = ublk_misc.this_device;
        dev->devt = MKDEV(MAJOR(ublk_chr_devt), minor);
-       dev->class = ublk_chr_class;
+       dev->class = &ublk_chr_class;
        dev->release = ublk_cdev_rel;
        device_initialize(dev);
 
@@ -2581,11 +2583,10 @@ static int __init ublk_init(void)
        if (ret)
                goto unregister_mis;
 
-       ublk_chr_class = class_create("ublk-char");
-       if (IS_ERR(ublk_chr_class)) {
-               ret = PTR_ERR(ublk_chr_class);
+       ret = class_register(&ublk_chr_class);
+       if (ret)
                goto free_chrdev_region;
-       }
+
        return 0;
 
 free_chrdev_region:
@@ -2603,7 +2604,7 @@ static void __exit ublk_exit(void)
        idr_for_each_entry(&ublk_index_idr, ub, id)
                ublk_remove(ub);
 
-       class_destroy(ublk_chr_class);
+       class_unregister(&ublk_chr_class);
        misc_deregister(&ublk_misc);
 
        idr_destroy(&ublk_index_idr);