USB: create module_usb_serial_driver macro

RFC In review Greg KH 2 participants 3 messages Feb 24, 2012 – Mar 10, 2012

Subsystems (3)

USB Driver core USB serial

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Greg KH

author maintainer

2012-02-24 23:38 UTC #0 lore raw

RFC 1/1 USB: create module_usb_serial_driver macro

Now that Alan Stern has cleaned up the usb serial driver registration, we have the ability to create a module_usb_serial_driver macro to make things a bit simpler, like the other *_driver macros created.

But, as we need two functions here, we can't reuse the existing module_driver() macro, so we need to roll our own.

Lars-Peter, or anyone else, am I missing something here and we can use module_driver() somehow, or even modify it, to work for subsystems that need 2 parameters for their function calls to register/deregister?

Actually, if we want to be tricky, we can go back to assigning the usb_driver in the usb_serial_driver structure, and just use that pointer in the first structure in the list as that option, but that's getting pretty opaque just to reuse a single macro...

Thoughts anyone?

thanks,

greg k-h

Here's a patch implementing module_usb_serial_driver() and it converts the pl2303 driver to use it, showing a nice cleanup.

Signed-off-by Greg Kroah-Hartman <[email protected]>

drivers/usb/serial/pl2303.c +1 ~~-17~~

@@ -855,23 +855,7 @@ static struct usb_serial_driver * const serial_drivers[] = {
 	&pl2303_device, NULL
 };
 
-static int __init pl2303_init(void)
-{
-	int retval;
-
-	retval = usb_serial_register_drivers(&pl2303_driver, serial_drivers);
-	if (retval == 0)
-		printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "\n");
-	return retval;
-}
-
-static void __exit pl2303_exit(void)
-{
-	usb_serial_deregister_drivers(&pl2303_driver, serial_drivers);
-}
-
-module_init(pl2303_init);
-module_exit(pl2303_exit);
+module_usb_serial_driver(pl2303_driver, serial_drivers);
 
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");

include/linux/usb/serial.h +28 -0

index 34c06a7..7b1db84 100644
@@ -406,5 +406,33 @@ do {									\
 	}								\
 } while (0)
 
+/*
+ * module_usb_serial_driver() - Helper macro for registering a USB Serial driver
+ * @__usb_driver: usb_driver struct to register
+ * @__serial_drivers: list of usb_serial drivers to register
+ *
+ * Helper macro for USB serial drivers which do not do anything special
+ * in module init/exit. This eliminates a lot of boilerplate. Each
+ * module may only use this macro once, and calling it replaces
+ * module_init() and module_exit()
+ *
+ * Note, we can't use the generic module_driver() call here, due to the
+ * two parameters in the usb_serial_* functions, so we roll our own here
+ * :(
+ */
+#define module_usb_serial_driver(__usb_driver, __serial_drivers)	\
+static int __init usb_serial_driver_init(void)				\
+{									\
+	return usb_serial_register_drivers(&(__usb_driver),		\
+					   (__serial_drivers));		\
+}									\
+module_init(usb_serial_driver_init);					\
+static void __exit usb_serial_driver_exit(void)				\
+{									\
+	return usb_serial_deregister_drivers(&(__usb_driver),		\
+					     (__serial_drivers));	\
+}									\
+module_exit(usb_serial_driver_exit);
+
 #endif /* __LINUX_USB_SERIAL_H */

Lars-Peter Clausen

2012-02-25 11:53 UTC #1 lore raw

Quoted 11 lines · Greg KH

Now that Alan Stern has cleaned up the usb serial driver registration, we have the ability to create a module_usb_serial_driver macro to make things a bit simpler, like the other *_driver macros created.
But, as we need two functions here, we can't reuse the existing module_driver() macro, so we need to roll our own.
Lars-Peter, or anyone else, am I missing something here and we can use module_driver() somehow, or even modify it, to work for subsystems that need 2 parameters for their function calls to register/deregister?

I suppose we can make module_driver a variadic macro and pass any additional parameters to the register and unregister functions. Patch attached.

- Lars

8<-------------------------------------------------------------------->8

Quoted 1 line

From 0d731970249b787748eccd6e81890c012a44e5a6 Mon Sep 17 00:00:00 2001

From: Lars-Peter Clausen <[email protected]>
Date: Sat, 25 Feb 2012 11:25:58 +0100
Subject: [PATCH] driver-core: Allow additional parameters for module_driver

Allow module_driver take additional parameters which will be passed to the register and unregister function calls. This allows it to be used in cases where additional parameters are required (e.g. usb_serial_register_drivers).

Signed-off-by Lars-Peter Clausen <[email protected]>

---
 include/linux/device.h |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

include/linux/device.h +4 -3

index b63fb39..bccccef 100644
@@ -1007,19 +1007,20 @@ extern long sysfs_deprecated;
  * @__driver: driver name
  * @__register: register function for this driver type
  * @__unregister: unregister function for this driver type
+ * @...: Additional arguments to be passed to __register and __unregister.
  *
  * Use this macro to construct bus specific macros for registering
  * drivers, and do not use it on its own.
  */
-#define module_driver(__driver, __register, __unregister) \
+#define module_driver(__driver, __register, __unregister, ...) \
 static int __init __driver##_init(void) \
 { \
-	return __register(&(__driver)); \
+	return __register(&(__driver) , ##__VA_ARGS__); \
 } \
 module_init(__driver##_init); \
 static void __exit __driver##_exit(void) \
 { \
-	__unregister(&(__driver)); \
+	__unregister(&(__driver) , ##__VA_ARGS__); \
 } \
 module_exit(__driver##_exit);

Signature · 1 line

1.7.2.5

Greg KH

author maintainer

2012-03-10 00:31 UTC #2 lore raw

Quoted 50 lines · Lars-Peter Clausen

Quoted 11 lines · Greg KH
Now that Alan Stern has cleaned up the usb serial driver registration, we have the ability to create a module_usb_serial_driver macro to make things a bit simpler, like the other *_driver macros created.
But, as we need two functions here, we can't reuse the existing module_driver() macro, so we need to roll our own.
Lars-Peter, or anyone else, am I missing something here and we can use module_driver() somehow, or even modify it, to work for subsystems that need 2 parameters for their function calls to register/deregister?
I suppose we can make module_driver a variadic macro and pass any additional parameters to the register and unregister functions. Patch attached.
- Lars
8<-------------------------------------------------------------------->8
Quoted 1 line
From 0d731970249b787748eccd6e81890c012a44e5a6 Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <[email protected]>
Date: Sat, 25 Feb 2012 11:25:58 +0100
Subject: [PATCH] driver-core: Allow additional parameters for module_driver
Allow module_driver take additional parameters which will be passed to the register and unregister function calls. This allows it to be used in cases where additional parameters are required (e.g. usb_serial_register_drivers).
Signed-off-by Lars-Peter Clausen <[email protected]>
---
 include/linux/device.h |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
include/linux/device.h +2 -1
index b63fb39..bccccef 100644
@@ -1007,19 +1007,20 @@ extern long sysfs_deprecated;
  * @__driver: driver name
  * @__register: register function for this driver type
  * @__unregister: unregister function for this driver type
+ * @...: Additional arguments to be passed to __register and __unregister.
  *
  * Use this macro to construct bus specific macros for registering
  * drivers, and do not use it on its own.
  */
-#define module_driver(__driver, __register, __unregister) \
+#define module_driver(__driver, __register, __unregister, ...) \
 static int __init __driver##_init(void) \
 { \

include/linux/device.h extern long sysfs_deprecated; · line 1025

Quoted 10 lines

include/linux/device.h +2 -2

-	return __register(&(__driver)); \
+	return __register(&(__driver) , ##__VA_ARGS__); \
 } \
 module_init(__driver##_init); \
 static void __exit __driver##_exit(void) \
 { \
-	__unregister(&(__driver)); \
+	__unregister(&(__driver) , ##__VA_ARGS__); \
 } \
 module_exit(__driver##_exit);

Nice, let me play with this and see how it works out, thanks.

greg k-h