[PATCH] spi: spidev: make spidev_class constant

[PATCH] spi: spidev: make spidev_class constant

[Greg Kroah-Hartman]

Now that the driver core allows for struct class to be in read-only
memory, we should make all 'class' structures declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at runtime.

Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/spi/spidev.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index d13dc15cc191..a078860a52ac 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -701,7 +701,9 @@ static const struct file_operations spidev_fops = {
  * It also simplifies memory management.
  */
 
-static struct class *spidev_class;
+static const struct class spidev_class = {
+	.name = "spidev",
+};
 
 static const struct spi_device_id spidev_spi_ids[] = {
 	{ .name = "dh2228fv" },
@@ -804,7 +806,7 @@ static int spidev_probe(struct spi_device *spi)
 		struct device *dev;
 
 		spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
-		dev = device_create(spidev_class, &spi->dev, spidev->devt,
+		dev = device_create(&spidev_class, &spi->dev, spidev->devt,
 				    spidev, "spidev%d.%d",
 				    spi->master->bus_num, spi_get_chipselect(spi, 0));
 		status = PTR_ERR_OR_ZERO(dev);
@@ -840,7 +842,7 @@ static void spidev_remove(struct spi_device *spi)
 	mutex_unlock(&spidev->spi_lock);
 
 	list_del(&spidev->device_entry);
-	device_destroy(spidev_class, spidev->devt);
+	device_destroy(&spidev_class, spidev->devt);
 	clear_bit(MINOR(spidev->devt), minors);
 	if (spidev->users == 0)
 		kfree(spidev);
@@ -878,15 +880,15 @@ static int __init spidev_init(void)
 	if (status < 0)
 		return status;
 
-	spidev_class = class_create("spidev");
-	if (IS_ERR(spidev_class)) {
+	status = class_register(&spidev_class);
+	if (status) {
 		unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
-		return PTR_ERR(spidev_class);
+		return status;
 	}
 
 	status = spi_register_driver(&spidev_spi_driver);
 	if (status < 0) {
-		class_destroy(spidev_class);
+		class_unregister(&spidev_class);
 		unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
 	}
 	return status;
@@ -896,7 +898,7 @@ module_init(spidev_init);
 static void __exit spidev_exit(void)
 {
 	spi_unregister_driver(&spidev_spi_driver);
-	class_destroy(spidev_class);
+	class_unregister(&spidev_class);
 	unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
 }
 module_exit(spidev_exit);
-- 
2.42.0

Re: [PATCH] spi: spidev: make spidev_class constant

[Mark Brown]

On Fri, 06 Oct 2023 15:58:40 +0200, Greg Kroah-Hartman wrote:
> Now that the driver core allows for struct class to be in read-only
> memory, we should make all 'class' structures declared at build time
> placing them into read-only memory, instead of having to be dynamically
> allocated at runtime.
> 
> 

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: spidev: make spidev_class constant
      commit: df22568ad8ed317db95acc11e1c08bae7a0fba5d

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark