Re: [PATCH 2/15] module_param: avoid bool abuse, add bint for special cases.

[Takashi Iwai]

At Thu, 15 Dec 2011 13:32:26 +1030,
Rusty Russell wrote:
> 
> For historical reasons, we allow module_param(bool) to take an int (or
> an unsigned int).  That's going away.
> 
> A few drivers really want an int: they set it to -1 and a parameter
> will set it to 0 or 1.  This sucks: reading them from sysfs will give
> 'Y' for both -1 and 1, but if we change it to an int, then the users
> might be broken (if they did "param" instead of "param=1").
> 
> Use a new 'bint' parser for them.
> 
> (ntfs has a different problem: it needs an int for debug_msgs because
> it's also exposed via sysctl.)
> 
> Cc: Steve Glendinning <steve.glendinning@xxxxxxxx>
> Cc: Jean Delvare <khali@xxxxxxxxxxxx>
> Cc: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>
> Cc: Hoang-Nam Nguyen <hnguyen@xxxxxxxxxx>
> Cc: Christoph Raisch <raisch@xxxxxxxxxx>
> Cc: Roland Dreier <roland@xxxxxxxxxx>
> Cc: Sean Hefty <sean.hefty@xxxxxxxxx>
> Cc: Hal Rosenstock <hal.rosenstock@xxxxxxxxx>
> Cc: linux390@xxxxxxxxxx
> Cc: Anton Altaparmakov <anton@xxxxxxxxxx>
> Cc: Jaroslav Kysela <perex@xxxxxxxx>
> Cc: Takashi Iwai <tiwai@xxxxxxx>

For the sound part,

  Acked-by: Takashi Iwai <tiwai@xxxxxxx>

It's a nice feature.  I know many drivers can be replaced with bint
gracefully now (e.g. i915 driver).


thanks,

Takashi


> Cc: lm-sensors@xxxxxxxxxxxxxx
> Cc: linux-rdma@xxxxxxxxxxxxxxx
> Cc: linux-s390@xxxxxxxxxxxxxxx
> Cc: linux-ntfs-dev@xxxxxxxxxxxxxxxxxxxxx
> Cc: alsa-devel@xxxxxxxxxxxxxxxx
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> ---
>  drivers/hwmon/emc2103.c                |    2 +-
>  drivers/infiniband/hw/ehca/ehca_main.c |    2 +-
>  drivers/s390/cio/cmf.c                 |    2 +-
>  fs/ntfs/super.c                        |    2 +-
>  include/linux/moduleparam.h            |    6 ++++++
>  kernel/params.c                        |   24 ++++++++++++++++++++++++
>  sound/pci/intel8x0.c                   |    4 ++--
>  7 files changed, 36 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/hwmon/emc2103.c b/drivers/hwmon/emc2103.c
> --- a/drivers/hwmon/emc2103.c
> +++ b/drivers/hwmon/emc2103.c
> @@ -55,7 +55,7 @@ static const u8 REG_TEMP_MAX[4] = { 0x34
>   * it.  Default is to leave the device in the state it's already in (-1).
>   * This parameter allows APD mode to be optionally forced on or off */
>  static int apd = -1;
> -module_param(apd, bool, 0);
> +module_param(apd, bint, 0);
>  MODULE_PARM_DESC(init, "Set to zero to disable anti-parallel diode mode");
>  
>  struct temperature {
> diff --git a/drivers/infiniband/hw/ehca/ehca_main.c b/drivers/infiniband/hw/ehca/ehca_main.c
> --- a/drivers/infiniband/hw/ehca/ehca_main.c
> +++ b/drivers/infiniband/hw/ehca/ehca_main.c
> @@ -82,7 +82,7 @@ module_param_named(port_act_time, ehca_p
>  module_param_named(poll_all_eqs,  ehca_poll_all_eqs,  bool, S_IRUGO);
>  module_param_named(static_rate,   ehca_static_rate,   int,  S_IRUGO);
>  module_param_named(scaling_code,  ehca_scaling_code,  bool, S_IRUGO);
> -module_param_named(lock_hcalls,   ehca_lock_hcalls,   bool, S_IRUGO);
> +module_param_named(lock_hcalls,   ehca_lock_hcalls,   bint, S_IRUGO);
>  module_param_named(number_of_cqs, ehca_max_cq,        int,  S_IRUGO);
>  module_param_named(number_of_qps, ehca_max_qp,        int,  S_IRUGO);
>  
> diff --git a/drivers/s390/cio/cmf.c b/drivers/s390/cio/cmf.c
> --- a/drivers/s390/cio/cmf.c
> +++ b/drivers/s390/cio/cmf.c
> @@ -98,7 +98,7 @@ enum cmb_format {
>   * enum cmb_format.
>   */
>  static int format = CMF_AUTODETECT;
> -module_param(format, bool, 0444);
> +module_param(format, bint, 0444);
>  
>  /**
>   * struct cmb_operations - functions to use depending on cmb_format
> diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
> --- a/fs/ntfs/super.c
> +++ b/fs/ntfs/super.c
> @@ -3198,7 +3198,7 @@ MODULE_DESCRIPTION("NTFS 1.2/3.x driver 
>  MODULE_VERSION(NTFS_VERSION);
>  MODULE_LICENSE("GPL");
>  #ifdef DEBUG
> -module_param(debug_msgs, bool, 0);
> +module_param(debug_msgs, bint, 0);
>  MODULE_PARM_DESC(debug_msgs, "Enable debug messages.");
>  #endif
>  
> diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
> --- a/include/linux/moduleparam.h
> +++ b/include/linux/moduleparam.h
> @@ -367,6 +367,12 @@ extern int param_set_invbool(const char 
>  extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
>  #define param_check_invbool(name, p) __param_check(name, p, bool)
>  
> +/* An int, which can only be set like a bool (though it shows as an int). */
> +extern struct kernel_param_ops param_ops_bint;
> +extern int param_set_bint(const char *val, const struct kernel_param *kp);
> +#define param_get_bint param_get_int
> +#define param_check_bint param_check_int
> +
>  /**
>   * module_param_array - a parameter which is an array of some type
>   * @name: the name of the array variable
> diff --git a/kernel/params.c b/kernel/params.c
> --- a/kernel/params.c
> +++ b/kernel/params.c
> @@ -369,6 +369,30 @@ struct kernel_param_ops param_ops_invboo
>  };
>  EXPORT_SYMBOL(param_ops_invbool);
>  
> +int param_set_bint(const char *val, const struct kernel_param *kp)
> +{
> +	struct kernel_param boolkp;
> +	bool v;
> +	int ret;
> +
> +	/* Match bool exactly, by re-using it. */
> +	boolkp = *kp;
> +	boolkp.arg = &v;
> +	boolkp.flags |= KPARAM_ISBOOL;
> +
> +	ret = param_set_bool(val, &boolkp);
> +	if (ret == 0)
> +		*(int *)kp->arg = v;
> +	return ret;
> +}
> +EXPORT_SYMBOL(param_set_bint);
> +
> +struct kernel_param_ops param_ops_bint = {
> +	.set = param_set_bint,
> +	.get = param_get_int,
> +};
> +EXPORT_SYMBOL(param_ops_bint);
> +
>  /* We break the rule and mangle the string. */
>  static int param_array(const char *name,
>  		       const char *val,
> diff --git a/sound/pci/intel8x0.c b/sound/pci/intel8x0.c
> --- a/sound/pci/intel8x0.c
> +++ b/sound/pci/intel8x0.c
> @@ -95,13 +95,13 @@ module_param(ac97_quirk, charp, 0444);
>  MODULE_PARM_DESC(ac97_quirk, "AC'97 workaround for strange hardware.");
>  module_param(buggy_semaphore, bool, 0444);
>  MODULE_PARM_DESC(buggy_semaphore, "Enable workaround for hardwares with problematic codec semaphores.");
> -module_param(buggy_irq, bool, 0444);
> +module_param(buggy_irq, bint, 0444);
>  MODULE_PARM_DESC(buggy_irq, "Enable workaround for buggy interrupts on some motherboards.");
>  module_param(xbox, bool, 0444);
>  MODULE_PARM_DESC(xbox, "Set to 1 for Xbox, if you have problems with the AC'97 codec detection.");
>  module_param(spdif_aclink, int, 0444);
>  MODULE_PARM_DESC(spdif_aclink, "S/PDIF over AC-link.");
> -module_param(inside_vm, bool, 0444);
> +module_param(inside_vm, bint, 0444);
>  MODULE_PARM_DESC(inside_vm, "KVM/Parallels optimization.");
>  
>  /* just for backward compatibility */
> 
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