diff mbox series

[1/3] staging: greybus: raw: make raw_class constant

Message ID 2023100533-broadband-hunk-9e91@gregkh
State New
Headers
Series [1/3] staging: greybus: raw: make raw_class constant |

Commit Message

Greg KH Oct. 5, 2023, 1:58 p.m. UTC 
  Now that the driver core allows for struct class to be in read-only
memory, making all 'class' structures to be declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: greybus-dev@lists.linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/greybus/raw.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

Comments

Johan Hovold Oct. 5, 2023, 3:49 p.m. UTC | #1 
On Thu, Oct 05, 2023 at 03:58:34PM +0200, Greg Kroah-Hartman wrote:
> Now that the driver core allows for struct class to be in read-only
> memory, making all 'class' structures to be declared at build time
> placing them into read-only memory, instead of having to be dynamically
> allocated at load time.
> 
> Cc: Johan Hovold <johan@kernel.org>
> Cc: Alex Elder <elder@kernel.org>
> Cc: greybus-dev@lists.linaro.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Reviewed-by: Johan Hovold <johan@kernel.org>
Deepak R Varma Oct. 6, 2023, 1:12 p.m. UTC | #2 
On Thu, Oct 05, 2023 at 03:58:34PM +0200, Greg Kroah-Hartman wrote:
> Now that the driver core allows for struct class to be in read-only

Hello Greg,
When you say "Now", has anything changed recently that facilitates this
improvement? Where can I read more about this change?

Thank you,
deepak.

> memory, making all 'class' structures to be declared at build time
> placing them into read-only memory, instead of having to be dynamically
> allocated at load time.
> 
> Cc: Johan Hovold <johan@kernel.org>
> Cc: Alex Elder <elder@kernel.org>
> Cc: greybus-dev@lists.linaro.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
Greg KH Oct. 6, 2023, 1:20 p.m. UTC | #3 
On Fri, Oct 06, 2023 at 06:42:00PM +0530, Deepak R Varma wrote:
> On Thu, Oct 05, 2023 at 03:58:34PM +0200, Greg Kroah-Hartman wrote:
> > Now that the driver core allows for struct class to be in read-only
> 
> Hello Greg,
> When you say "Now", has anything changed recently that facilitates this
> improvement?

Yes.  Well, it showed up in the 6.4 kernel, so not that long ago.

> Where can I read more about this change?

Running:
	git log --oneline --author=gregkh v6.3..v6.4 drivers/base/
will show you the some of work that happened here to make this possible.
There was work done to the driver core, and the kobject core in earlier
kernel releases that the changes in 6.4 built on top of.

thanks,

greg k-h
diff mbox series

Patch

diff --git a/drivers/staging/greybus/raw.c b/drivers/staging/greybus/raw.c
index 8bca8cb12cc6..a00978c8e1d2 100644
--- a/drivers/staging/greybus/raw.c
+++ b/drivers/staging/greybus/raw.c
@@ -32,7 +32,10 @@  struct raw_data {
 	u8 data[];
 };
 
-static struct class *raw_class;
+static const struct class raw_class = {
+	.name = "gb_raw",
+};
+
 static int raw_major;
 static const struct file_operations raw_fops;
 static DEFINE_IDA(minors);
@@ -195,7 +198,7 @@  static int gb_raw_probe(struct gb_bundle *bundle,
 	if (retval)
 		goto error_connection_disable;
 
-	raw->device = device_create(raw_class, &connection->bundle->dev,
+	raw->device = device_create(&raw_class, &connection->bundle->dev,
 				    raw->dev, raw, "gb!raw%d", minor);
 	if (IS_ERR(raw->device)) {
 		retval = PTR_ERR(raw->device);
@@ -229,7 +232,7 @@  static void gb_raw_disconnect(struct gb_bundle *bundle)
 	struct raw_data *temp;
 
 	// FIXME - handle removing a connection when the char device node is open.
-	device_destroy(raw_class, raw->dev);
+	device_destroy(&raw_class, raw->dev);
 	cdev_del(&raw->cdev);
 	gb_connection_disable(connection);
 	ida_simple_remove(&minors, MINOR(raw->dev));
@@ -340,11 +343,9 @@  static int raw_init(void)
 	dev_t dev;
 	int retval;
 
-	raw_class = class_create("gb_raw");
-	if (IS_ERR(raw_class)) {
-		retval = PTR_ERR(raw_class);
+	retval = class_register(&raw_class);
+	if (retval)
 		goto error_class;
-	}
 
 	retval = alloc_chrdev_region(&dev, 0, NUM_MINORS, "gb_raw");
 	if (retval < 0)
@@ -361,7 +362,7 @@  static int raw_init(void)
 error_gb:
 	unregister_chrdev_region(dev, NUM_MINORS);
 error_chrdev:
-	class_destroy(raw_class);
+	class_unregister(&raw_class);
 error_class:
 	return retval;
 }
@@ -371,7 +372,7 @@  static void __exit raw_exit(void)
 {
 	greybus_deregister(&gb_raw_driver);
 	unregister_chrdev_region(MKDEV(raw_major, 0), NUM_MINORS);
-	class_destroy(raw_class);
+	class_unregister(&raw_class);
 	ida_destroy(&minors);
 }
 module_exit(raw_exit);