bsg: make bsg_class a static const structure

Now that the driver core allows for struct class to be in read-only
memory, move the bsg_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: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-scsi@vger.kernel.org
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/20230620180129.645646-8-gregkh@linuxfoundation.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bsg.c b/block/bsg.c
index bec4027842b31e7ab52f6ed2f5456dd597c7bfb2..1a9396a3b7d72725962aad85ec8591a15902effd 100644 (file)
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -39,7 +39,7 @@ static inline struct bsg_device *to_bsg_device(struct inode *inode)
 #define BSG_MAX_DEVS           32768
 
 static DEFINE_IDA(bsg_minor_ida);
-static struct class *bsg_class;
+static const struct class bsg_class;
 static int bsg_major;
 
 static unsigned int bsg_timeout(struct bsg_device *bd, struct sg_io_v4 *hdr)
@@ -208,7 +208,7 @@ struct bsg_device *bsg_register_queue(struct request_queue *q,
                return ERR_PTR(ret);
        }
        bd->device.devt = MKDEV(bsg_major, ret);
-       bd->device.class = bsg_class;
+       bd->device.class = &bsg_class;
        bd->device.parent = parent;
        bd->device.release = bsg_device_release;
        dev_set_name(&bd->device, "%s", name);
@@ -242,15 +242,19 @@ static char *bsg_devnode(const struct device *dev, umode_t *mode)
        return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
 }
 
+static const struct class bsg_class = {
+       .name           = "bsg",
+       .devnode        = bsg_devnode,
+};
+
 static int __init bsg_init(void)
 {
        dev_t devid;
        int ret;
 
-       bsg_class = class_create("bsg");
-       if (IS_ERR(bsg_class))
-               return PTR_ERR(bsg_class);
-       bsg_class->devnode = bsg_devnode;
+       ret = class_register(&bsg_class);
+       if (ret)
+               return ret;
 
        ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
        if (ret)
@@ -262,7 +266,7 @@ static int __init bsg_init(void)
        return 0;
 
 destroy_bsg_class:
-       class_destroy(bsg_class);
+       class_unregister(&bsg_class);
        return ret;
 }