Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1290718 > unrolled thread

[PATCH 0/3] leds: avoid module usage in non-modular code

Back to article view | Back to linux.kernel

Contents

  [PATCH 0/3] leds: avoid module usage in non-modular code Paul Gortmaker <paul.gortmaker@windriver.com> - 2015-12-13 22:50 +0100
    [PATCH 3/3] drivers/leds: make leds-syscon.c explicitly non-modular Paul Gortmaker <paul.gortmaker@windriver.com> - 2015-12-13 22:50 +0100
    Re: [PATCH 0/3] leds: avoid module usage in non-modular code Jacek Anaszewski <j.anaszewski@samsung.com> - 2015-12-14 10:30 +0100

#1290718 — [PATCH 0/3] leds: avoid module usage in non-modular code

This series of commits is a part of a larger project to ensure
people don't reference modular support functions in non-modular
code.  Overall there was roughly 5k lines of dead code in the
kernel due to this.  So far we've fixed several areas, like tty,
x86, net, ... and we continue to work on other areas.

There are several reasons to not use module support for code that
can never be built as a module, but the big ones are:

 (1) it is easy to accidentally code up unused module_exit and remove code
 (2) it can be misleading when reading the source, thinking it can be
      modular when the Makefile and/or Kconfig prohibit it
 (3) it requires the include of the module.h header file which in turn
     includes nearly everything else.

For the LED subsystem, there are just three commits.  Two are basically
trivial remapping to the appropriate non-modular counterparts.  The
third also has a change to block driver unbinding since that doesn't
make any sense and it allows us to delete the .remove code.  We've
already made similar unbind changes like this in drivers/tty.

Patches created on linux-next and build tested for ARM allmodconfig.

Paul.
---

Cc: Bryan Wu <cooloney@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: linux-leds@vger.kernel.org

Paul Gortmaker (3):
  drivers/leds: make trigger/ledtrig-cpu.c driver explicitly non-modular
  drivers/leds: make trigger/ledtrig-ide-disk.c driver explicitly non-modular
  drivers/leds: make leds-syscon.c explicitly non-modular

 drivers/leds/leds-syscon.c              | 18 +++---------------
 drivers/leds/trigger/ledtrig-cpu.c      | 26 +-------------------------
 drivers/leds/trigger/ledtrig-ide-disk.c | 14 +-------------
 3 files changed, 5 insertions(+), 53 deletions(-)

-- 
2.6.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1290719 — [PATCH 3/3] drivers/leds: make leds-syscon.c explicitly non-modular

The Kconfig currently controlling compilation of this code is:

drivers/leds/Kconfig:config LEDS_SYSCON
drivers/leds/Kconfig:   bool "LED support for LEDs on system controllers"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
Cc: linux-leds@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 drivers/leds/leds-syscon.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/leds/leds-syscon.c b/drivers/leds/leds-syscon.c
index b88900d721e4..3be40f74f12a 100644
--- a/drivers/leds/leds-syscon.c
+++ b/drivers/leds/leds-syscon.c
@@ -20,7 +20,7 @@
  * MA 02111-1307 USA
  */
 #include <linux/io.h>
-#include <linux/module.h>
+#include <linux/init.h>
 #include <linux/of_device.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
@@ -139,29 +139,17 @@ static int syscon_led_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int syscon_led_remove(struct platform_device *pdev)
-{
-	struct syscon_led *sled = platform_get_drvdata(pdev);
-
-	led_classdev_unregister(&sled->cdev);
-	/* Turn it off */
-	regmap_update_bits(sled->map, sled->offset, sled->mask, 0);
-	return 0;
-}
-
 static const struct of_device_id of_syscon_leds_match[] = {
 	{ .compatible = "register-bit-led", },
 	{},
 };
 
-MODULE_DEVICE_TABLE(of, of_syscon_leds_match);
-
 static struct platform_driver syscon_led_driver = {
 	.probe		= syscon_led_probe,
-	.remove		= syscon_led_remove,
 	.driver		= {
 		.name	= "leds-syscon",
 		.of_match_table = of_syscon_leds_match,
+		.suppress_bind_attrs = true,
 	},
 };
-module_platform_driver(syscon_led_driver);
+builtin_platform_driver(syscon_led_driver);
-- 
2.6.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1290999

On 12/13/2015 10:45 PM, Paul Gortmaker wrote:
> This series of commits is a part of a larger project to ensure
> people don't reference modular support functions in non-modular
> code.  Overall there was roughly 5k lines of dead code in the
> kernel due to this.  So far we've fixed several areas, like tty,
> x86, net, ... and we continue to work on other areas.
>
> There are several reasons to not use module support for code that
> can never be built as a module, but the big ones are:
>
>   (1) it is easy to accidentally code up unused module_exit and remove code
>   (2) it can be misleading when reading the source, thinking it can be
>        modular when the Makefile and/or Kconfig prohibit it
>   (3) it requires the include of the module.h header file which in turn
>       includes nearly everything else.
>
> For the LED subsystem, there are just three commits.  Two are basically
> trivial remapping to the appropriate non-modular counterparts.  The
> third also has a change to block driver unbinding since that doesn't
> make any sense and it allows us to delete the .remove code.  We've
> already made similar unbind changes like this in drivers/tty.
>
> Patches created on linux-next and build tested for ARM allmodconfig.
>
> Paul.
> ---
>
> Cc: Bryan Wu <cooloney@gmail.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
> Cc: Richard Purdie <rpurdie@rpsys.net>
> Cc: linux-leds@vger.kernel.org
>
> Paul Gortmaker (3):
>    drivers/leds: make trigger/ledtrig-cpu.c driver explicitly non-modular
>    drivers/leds: make trigger/ledtrig-ide-disk.c driver explicitly non-modular
>    drivers/leds: make leds-syscon.c explicitly non-modular
>
>   drivers/leds/leds-syscon.c              | 18 +++---------------
>   drivers/leds/trigger/ledtrig-cpu.c      | 26 +-------------------------
>   drivers/leds/trigger/ledtrig-ide-disk.c | 14 +-------------
>   3 files changed, 5 insertions(+), 53 deletions(-)
>

Patch set applied, thanks.

-- 
Best Regards,
Jacek Anaszewski
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web