[03/16] lib,treewide: add new match_string() helper/macro
diff mbox series

Message ID 20190508112842.11654-5-alexandru.ardelean@analog.com
State New
Headers show
Series
  • treewide: fix match_string() helper when array size
Related show

Commit Message

Alexandru Ardelean May 8, 2019, 11:28 a.m. UTC
This change re-introduces `match_string()` as a macro that uses
ARRAY_SIZE() to compute the size of the array.
The macro is added in all the places that do
`match_string(_a, ARRAY_SIZE(_a), s)`, since the change is pretty
straightforward.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/clk/bcm/clk-bcm2835.c                    | 4 +---
 drivers/gpio/gpiolib-of.c                        | 2 +-
 drivers/gpu/drm/i915/intel_pipe_crc.c            | 2 +-
 drivers/mfd/omap-usb-host.c                      | 2 +-
 drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c | 2 +-
 drivers/pci/pcie/aer.c                           | 2 +-
 drivers/usb/common/common.c                      | 4 ++--
 drivers/usb/typec/class.c                        | 8 +++-----
 drivers/usb/typec/tps6598x.c                     | 2 +-
 drivers/vfio/vfio.c                              | 4 +---
 include/linux/string.h                           | 9 +++++++++
 sound/firewire/oxfw/oxfw.c                       | 2 +-
 sound/soc/codecs/max98088.c                      | 2 +-
 sound/soc/codecs/max98095.c                      | 2 +-
 14 files changed, 25 insertions(+), 22 deletions(-)

Comments

Andy Shevchenko May 8, 2019, 1:11 p.m. UTC | #1
On Wed, May 08, 2019 at 02:28:29PM +0300, Alexandru Ardelean wrote:
> This change re-introduces `match_string()` as a macro that uses
> ARRAY_SIZE() to compute the size of the array.
> The macro is added in all the places that do
> `match_string(_a, ARRAY_SIZE(_a), s)`, since the change is pretty
> straightforward.

Can you split include/linux/ change from the rest?

> 
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> ---
>  drivers/clk/bcm/clk-bcm2835.c                    | 4 +---
>  drivers/gpio/gpiolib-of.c                        | 2 +-
>  drivers/gpu/drm/i915/intel_pipe_crc.c            | 2 +-
>  drivers/mfd/omap-usb-host.c                      | 2 +-
>  drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c | 2 +-
>  drivers/pci/pcie/aer.c                           | 2 +-
>  drivers/usb/common/common.c                      | 4 ++--
>  drivers/usb/typec/class.c                        | 8 +++-----
>  drivers/usb/typec/tps6598x.c                     | 2 +-
>  drivers/vfio/vfio.c                              | 4 +---
>  include/linux/string.h                           | 9 +++++++++
>  sound/firewire/oxfw/oxfw.c                       | 2 +-
>  sound/soc/codecs/max98088.c                      | 2 +-
>  sound/soc/codecs/max98095.c                      | 2 +-
>  14 files changed, 25 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
> index a775f6a1f717..1ab388590ead 100644
> --- a/drivers/clk/bcm/clk-bcm2835.c
> +++ b/drivers/clk/bcm/clk-bcm2835.c
> @@ -1390,9 +1390,7 @@ static struct clk_hw *bcm2835_register_clock(struct bcm2835_cprman *cprman,
>  	for (i = 0; i < data->num_mux_parents; i++) {
>  		parents[i] = data->parents[i];
>  
> -		ret = __match_string(cprman_parent_names,
> -				     ARRAY_SIZE(cprman_parent_names),
> -				     parents[i]);
> +		ret = match_string(cprman_parent_names, parents[i]);
>  		if (ret >= 0)
>  			parents[i] = cprman->real_parent_names[ret];
>  	}
> diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
> index 27d6f04ab58e..71e886869d78 100644
> --- a/drivers/gpio/gpiolib-of.c
> +++ b/drivers/gpio/gpiolib-of.c
> @@ -279,7 +279,7 @@ static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *
>  	if (!con_id)
>  		return ERR_PTR(-ENOENT);
>  
> -	i = __match_string(whitelist, ARRAY_SIZE(whitelist), con_id);
> +	i = match_string(whitelist, con_id);
>  	if (i < 0)
>  		return ERR_PTR(-ENOENT);
>  
> diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c b/drivers/gpu/drm/i915/intel_pipe_crc.c
> index 286fad1f0e08..6fc4f3d3d1f6 100644
> --- a/drivers/gpu/drm/i915/intel_pipe_crc.c
> +++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
> @@ -449,7 +449,7 @@ display_crc_ctl_parse_source(const char *buf, enum intel_pipe_crc_source *s)
>  		return 0;
>  	}
>  
> -	i = __match_string(pipe_crc_sources, ARRAY_SIZE(pipe_crc_sources), buf);
> +	i = match_string(pipe_crc_sources, buf);
>  	if (i < 0)
>  		return i;
>  
> diff --git a/drivers/mfd/omap-usb-host.c b/drivers/mfd/omap-usb-host.c
> index 9aaacb5bdb26..53dff34c0afc 100644
> --- a/drivers/mfd/omap-usb-host.c
> +++ b/drivers/mfd/omap-usb-host.c
> @@ -509,7 +509,7 @@ static int usbhs_omap_get_dt_pdata(struct device *dev,
>  			continue;
>  
>  		/* get 'enum usbhs_omap_port_mode' from port mode string */
> -		ret = __match_string(port_modes, ARRAY_SIZE(port_modes), mode);
> +		ret = match_string(port_modes, mode);
>  		if (ret < 0) {
>  			dev_warn(dev, "Invalid port%d-mode \"%s\" in device tree\n",
>  					i, mode);
> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
> index 59ce3ff35553..778b4dfd8b75 100644
> --- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
> +++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
> @@ -667,7 +667,7 @@ iwl_dbgfs_bt_force_ant_write(struct iwl_mvm *mvm, char *buf,
>  	};
>  	int ret, bt_force_ant_mode;
>  
> -	ret = __match_string(modes_str, ARRAY_SIZE(modes_str), buf);
> +	ret = match_string(modes_str, buf);
>  	if (ret < 0)
>  		return ret;
>  
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 41a0773a1cbc..2278caba109c 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -203,7 +203,7 @@ void pcie_ecrc_get_policy(char *str)
>  {
>  	int i;
>  
> -	i = __match_string(ecrc_policy_str, ARRAY_SIZE(ecrc_policy_str), str);
> +	i = match_string(ecrc_policy_str, str);
>  	if (i < 0)
>  		return;
>  
> diff --git a/drivers/usb/common/common.c b/drivers/usb/common/common.c
> index bca0c404c6ca..5a651d311d38 100644
> --- a/drivers/usb/common/common.c
> +++ b/drivers/usb/common/common.c
> @@ -68,7 +68,7 @@ enum usb_device_speed usb_get_maximum_speed(struct device *dev)
>  	if (ret < 0)
>  		return USB_SPEED_UNKNOWN;
>  
> -	ret = __match_string(speed_names, ARRAY_SIZE(speed_names), maximum_speed);
> +	ret = match_string(speed_names, maximum_speed);
>  
>  	return (ret < 0) ? USB_SPEED_UNKNOWN : ret;
>  }
> @@ -106,7 +106,7 @@ static enum usb_dr_mode usb_get_dr_mode_from_string(const char *str)
>  {
>  	int ret;
>  
> -	ret = __match_string(usb_dr_modes, ARRAY_SIZE(usb_dr_modes), str);
> +	ret = match_string(usb_dr_modes, str);
>  	return (ret < 0) ? USB_DR_MODE_UNKNOWN : ret;
>  }
>  
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 4abc5a76ec51..38ac776cba8a 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -1409,8 +1409,7 @@ EXPORT_SYMBOL_GPL(typec_set_pwr_opmode);
>   */
>  int typec_find_port_power_role(const char *name)
>  {
> -	return __match_string(typec_port_power_roles,
> -			      ARRAY_SIZE(typec_port_power_roles), name);
> +	return match_string(typec_port_power_roles, name);
>  }
>  EXPORT_SYMBOL_GPL(typec_find_port_power_role);
>  
> @@ -1424,7 +1423,7 @@ EXPORT_SYMBOL_GPL(typec_find_port_power_role);
>   */
>  int typec_find_power_role(const char *name)
>  {
> -	return __match_string(typec_roles, ARRAY_SIZE(typec_roles), name);
> +	return match_string(typec_roles, name);
>  }
>  EXPORT_SYMBOL_GPL(typec_find_power_role);
>  
> @@ -1438,8 +1437,7 @@ EXPORT_SYMBOL_GPL(typec_find_power_role);
>   */
>  int typec_find_port_data_role(const char *name)
>  {
> -	return __match_string(typec_port_data_roles,
> -			      ARRAY_SIZE(typec_port_data_roles), name);
> +	return match_string(typec_port_data_roles, name);
>  }
>  EXPORT_SYMBOL_GPL(typec_find_port_data_role);
>  
> diff --git a/drivers/usb/typec/tps6598x.c b/drivers/usb/typec/tps6598x.c
> index 0389e4391faf..0c4e47868590 100644
> --- a/drivers/usb/typec/tps6598x.c
> +++ b/drivers/usb/typec/tps6598x.c
> @@ -423,7 +423,7 @@ static int tps6598x_check_mode(struct tps6598x *tps)
>  	if (ret)
>  		return ret;
>  
> -	switch (__match_string(modes, ARRAY_SIZE(modes), mode)) {
> +	switch (match_string(modes, mode)) {
>  	case TPS_MODE_APP:
>  		return 0;
>  	case TPS_MODE_BOOT:
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index b31585ecf48f..fe8283d3781b 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -637,9 +637,7 @@ static bool vfio_dev_whitelisted(struct device *dev, struct device_driver *drv)
>  			return true;
>  	}
>  
> -	return __match_string(vfio_driver_whitelist,
> -			      ARRAY_SIZE(vfio_driver_whitelist),
> -			      drv->name) >= 0;
> +	return match_string(vfio_driver_whitelist, drv->name) >= 0;
>  }
>  
>  /*
> diff --git a/include/linux/string.h b/include/linux/string.h
> index 531d04308ff9..07e9f89088df 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -194,6 +194,15 @@ static inline int strtobool(const char *s, bool *res)
>  int __match_string(const char * const *array, size_t n, const char *string);
>  int __sysfs_match_string(const char * const *array, size_t n, const char *s);
>  
> +/**
> + * match_string - matches given string in an array
> + * @_a: array of strings
> + * @_s: string to match with
> + *
> + * Helper for __match_string(). Calculates the size of @a automatically.
> + */
> +#define match_string(_a, _s) __match_string(_a, ARRAY_SIZE(_a), _s)
> +
>  /**
>   * sysfs_match_string - matches given string in an array
>   * @_a: array of strings
> diff --git a/sound/firewire/oxfw/oxfw.c b/sound/firewire/oxfw/oxfw.c
> index 9ec5316f3bb5..433fc84c4f90 100644
> --- a/sound/firewire/oxfw/oxfw.c
> +++ b/sound/firewire/oxfw/oxfw.c
> @@ -57,7 +57,7 @@ static bool detect_loud_models(struct fw_unit *unit)
>  	if (err < 0)
>  		return false;
>  
> -	return __match_string(models, ARRAY_SIZE(models), model) >= 0;
> +	return match_string(models, model) >= 0;
>  }
>  
>  static int name_card(struct snd_oxfw *oxfw)
> diff --git a/sound/soc/codecs/max98088.c b/sound/soc/codecs/max98088.c
> index 3ef743075bda..911ffe84c37e 100644
> --- a/sound/soc/codecs/max98088.c
> +++ b/sound/soc/codecs/max98088.c
> @@ -1405,7 +1405,7 @@ static int max98088_get_channel(struct snd_soc_component *component, const char
>  {
>  	int ret;
>  
> -	ret = __match_string(eq_mode_name, ARRAY_SIZE(eq_mode_name), name);
> +	ret = match_string(eq_mode_name, name);
>  	if (ret < 0)
>  		dev_err(component->dev, "Bad EQ channel name '%s'\n", name);
>  	return ret;
> diff --git a/sound/soc/codecs/max98095.c b/sound/soc/codecs/max98095.c
> index cd69916d5dcb..d182d45d0c83 100644
> --- a/sound/soc/codecs/max98095.c
> +++ b/sound/soc/codecs/max98095.c
> @@ -1636,7 +1636,7 @@ static int max98095_get_bq_channel(struct snd_soc_component *component,
>  {
>  	int ret;
>  
> -	ret = __match_string(bq_mode_name, ARRAY_SIZE(bq_mode_name), name);
> +	ret = match_string(bq_mode_name, name);
>  	if (ret < 0)
>  		dev_err(component->dev, "Bad biquad channel name '%s'\n", name);
>  	return ret;
> -- 
> 2.17.1
>
Greg KH May 8, 2019, 1:18 p.m. UTC | #2
On Wed, May 08, 2019 at 04:11:28PM +0300, Andy Shevchenko wrote:
> On Wed, May 08, 2019 at 02:28:29PM +0300, Alexandru Ardelean wrote:
> > This change re-introduces `match_string()` as a macro that uses
> > ARRAY_SIZE() to compute the size of the array.
> > The macro is added in all the places that do
> > `match_string(_a, ARRAY_SIZE(_a), s)`, since the change is pretty
> > straightforward.
> 
> Can you split include/linux/ change from the rest?

That would break the build, why do you want it split out?  This makes
sense all as a single patch to me.

thanks,

greg k-h
Alexandru Ardelean May 8, 2019, 1:22 p.m. UTC | #3
On Wed, 2019-05-08 at 15:18 +0200, Greg KH wrote:
> 
> 
> On Wed, May 08, 2019 at 04:11:28PM +0300, Andy Shevchenko wrote:
> > On Wed, May 08, 2019 at 02:28:29PM +0300, Alexandru Ardelean wrote:
> > > This change re-introduces `match_string()` as a macro that uses
> > > ARRAY_SIZE() to compute the size of the array.
> > > The macro is added in all the places that do
> > > `match_string(_a, ARRAY_SIZE(_a), s)`, since the change is pretty
> > > straightforward.
> > 
> > Can you split include/linux/ change from the rest?
> 
> That would break the build, why do you want it split out?  This makes
> sense all as a single patch to me.
> 

Not really.
It would be just be the new match_string() helper/macro in a new commit.
And the conversions of the simple users of match_string() (the ones using
ARRAY_SIZE()) in another commit.

Thanks
Alex

> thanks,
> 
> greg k-h
Alexandru Ardelean May 10, 2019, 9:15 a.m. UTC | #4
On Wed, 2019-05-08 at 16:22 +0300, Alexandru Ardelean wrote:
> On Wed, 2019-05-08 at 15:18 +0200, Greg KH wrote:
> > 
> > 
> > On Wed, May 08, 2019 at 04:11:28PM +0300, Andy Shevchenko wrote:
> > > On Wed, May 08, 2019 at 02:28:29PM +0300, Alexandru Ardelean wrote:
> > > > This change re-introduces `match_string()` as a macro that uses
> > > > ARRAY_SIZE() to compute the size of the array.
> > > > The macro is added in all the places that do
> > > > `match_string(_a, ARRAY_SIZE(_a), s)`, since the change is pretty
> > > > straightforward.
> > > 
> > > Can you split include/linux/ change from the rest?
> > 
> > That would break the build, why do you want it split out?  This makes
> > sense all as a single patch to me.
> > 
> 
> Not really.
> It would be just be the new match_string() helper/macro in a new commit.
> And the conversions of the simple users of match_string() (the ones using
> ARRAY_SIZE()) in another commit.
> 

I should have asked in my previous reply.
Leave this as-is or re-formulate in 2 patches ?

No strong preference from my side.

Thanks
Alex

> Thanks
> Alex
> 
> > thanks,
> > 
> > greg k-h
Andy Shevchenko May 10, 2019, 2:34 p.m. UTC | #5
On Fri, May 10, 2019 at 09:15:27AM +0000, Ardelean, Alexandru wrote:
> On Wed, 2019-05-08 at 16:22 +0300, Alexandru Ardelean wrote:
> > On Wed, 2019-05-08 at 15:18 +0200, Greg KH wrote:
> > > On Wed, May 08, 2019 at 04:11:28PM +0300, Andy Shevchenko wrote:
> > > > On Wed, May 08, 2019 at 02:28:29PM +0300, Alexandru Ardelean wrote:

> > > > Can you split include/linux/ change from the rest?
> > > 
> > > That would break the build, why do you want it split out?  This makes
> > > sense all as a single patch to me.
> > > 
> > 
> > Not really.
> > It would be just be the new match_string() helper/macro in a new commit.
> > And the conversions of the simple users of match_string() (the ones using
> > ARRAY_SIZE()) in another commit.
> > 
> 
> I should have asked in my previous reply.
> Leave this as-is or re-formulate in 2 patches ?

Depends on on what you would like to spend your time: collecting Acks for all
pieces in treewide patch or send new API first followed up by per driver /
module update in next cycle.

I also have no strong preference.
And I think it's good to add Heikki Krogerus to Cc list for both patch series,
since he is the author of sysfs variant and may have something to comment on
the rest.
Alexandru Ardelean May 13, 2019, 7 a.m. UTC | #6
On Fri, 2019-05-10 at 17:34 +0300, andriy.shevchenko@linux.intel.com wrote:
> [External]
> 
> 
> On Fri, May 10, 2019 at 09:15:27AM +0000, Ardelean, Alexandru wrote:
> > On Wed, 2019-05-08 at 16:22 +0300, Alexandru Ardelean wrote:
> > > On Wed, 2019-05-08 at 15:18 +0200, Greg KH wrote:
> > > > On Wed, May 08, 2019 at 04:11:28PM +0300, Andy Shevchenko wrote:
> > > > > On Wed, May 08, 2019 at 02:28:29PM +0300, Alexandru Ardelean
> > > > > wrote:
> > > > > Can you split include/linux/ change from the rest?
> > > > 
> > > > That would break the build, why do you want it split out?  This
> > > > makes
> > > > sense all as a single patch to me.
> > > > 
> > > 
> > > Not really.
> > > It would be just be the new match_string() helper/macro in a new
> > > commit.
> > > And the conversions of the simple users of match_string() (the ones
> > > using
> > > ARRAY_SIZE()) in another commit.
> > > 
> > 
> > I should have asked in my previous reply.
> > Leave this as-is or re-formulate in 2 patches ?
> 
> Depends on on what you would like to spend your time: collecting Acks for
> all
> pieces in treewide patch or send new API first followed up by per driver
> /
> module update in next cycle.

I actually would have preferred new API first, with the current
`match_string()` -> `__match_string()` rename from the start, but I wasn't
sure. I am still navigating through how feedbacks are working in this
realm.

I'll send a V2 with the API change-first/only; should be a smaller list.
Then see about follow-ups/changes per subsystems.

> 
> I also have no strong preference.
> And I think it's good to add Heikki Krogerus to Cc list for both patch
> series,
> since he is the author of sysfs variant and may have something to comment
> on
> the rest.

Thanks for the reference.

> 
> --
> With Best Regards,
> Andy Shevchenko
> 
>

Patch
diff mbox series

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index a775f6a1f717..1ab388590ead 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1390,9 +1390,7 @@  static struct clk_hw *bcm2835_register_clock(struct bcm2835_cprman *cprman,
 	for (i = 0; i < data->num_mux_parents; i++) {
 		parents[i] = data->parents[i];
 
-		ret = __match_string(cprman_parent_names,
-				     ARRAY_SIZE(cprman_parent_names),
-				     parents[i]);
+		ret = match_string(cprman_parent_names, parents[i]);
 		if (ret >= 0)
 			parents[i] = cprman->real_parent_names[ret];
 	}
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 27d6f04ab58e..71e886869d78 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -279,7 +279,7 @@  static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *
 	if (!con_id)
 		return ERR_PTR(-ENOENT);
 
-	i = __match_string(whitelist, ARRAY_SIZE(whitelist), con_id);
+	i = match_string(whitelist, con_id);
 	if (i < 0)
 		return ERR_PTR(-ENOENT);
 
diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c b/drivers/gpu/drm/i915/intel_pipe_crc.c
index 286fad1f0e08..6fc4f3d3d1f6 100644
--- a/drivers/gpu/drm/i915/intel_pipe_crc.c
+++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
@@ -449,7 +449,7 @@  display_crc_ctl_parse_source(const char *buf, enum intel_pipe_crc_source *s)
 		return 0;
 	}
 
-	i = __match_string(pipe_crc_sources, ARRAY_SIZE(pipe_crc_sources), buf);
+	i = match_string(pipe_crc_sources, buf);
 	if (i < 0)
 		return i;
 
diff --git a/drivers/mfd/omap-usb-host.c b/drivers/mfd/omap-usb-host.c
index 9aaacb5bdb26..53dff34c0afc 100644
--- a/drivers/mfd/omap-usb-host.c
+++ b/drivers/mfd/omap-usb-host.c
@@ -509,7 +509,7 @@  static int usbhs_omap_get_dt_pdata(struct device *dev,
 			continue;
 
 		/* get 'enum usbhs_omap_port_mode' from port mode string */
-		ret = __match_string(port_modes, ARRAY_SIZE(port_modes), mode);
+		ret = match_string(port_modes, mode);
 		if (ret < 0) {
 			dev_warn(dev, "Invalid port%d-mode \"%s\" in device tree\n",
 					i, mode);
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
index 59ce3ff35553..778b4dfd8b75 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c
@@ -667,7 +667,7 @@  iwl_dbgfs_bt_force_ant_write(struct iwl_mvm *mvm, char *buf,
 	};
 	int ret, bt_force_ant_mode;
 
-	ret = __match_string(modes_str, ARRAY_SIZE(modes_str), buf);
+	ret = match_string(modes_str, buf);
 	if (ret < 0)
 		return ret;
 
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 41a0773a1cbc..2278caba109c 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -203,7 +203,7 @@  void pcie_ecrc_get_policy(char *str)
 {
 	int i;
 
-	i = __match_string(ecrc_policy_str, ARRAY_SIZE(ecrc_policy_str), str);
+	i = match_string(ecrc_policy_str, str);
 	if (i < 0)
 		return;
 
diff --git a/drivers/usb/common/common.c b/drivers/usb/common/common.c
index bca0c404c6ca..5a651d311d38 100644
--- a/drivers/usb/common/common.c
+++ b/drivers/usb/common/common.c
@@ -68,7 +68,7 @@  enum usb_device_speed usb_get_maximum_speed(struct device *dev)
 	if (ret < 0)
 		return USB_SPEED_UNKNOWN;
 
-	ret = __match_string(speed_names, ARRAY_SIZE(speed_names), maximum_speed);
+	ret = match_string(speed_names, maximum_speed);
 
 	return (ret < 0) ? USB_SPEED_UNKNOWN : ret;
 }
@@ -106,7 +106,7 @@  static enum usb_dr_mode usb_get_dr_mode_from_string(const char *str)
 {
 	int ret;
 
-	ret = __match_string(usb_dr_modes, ARRAY_SIZE(usb_dr_modes), str);
+	ret = match_string(usb_dr_modes, str);
 	return (ret < 0) ? USB_DR_MODE_UNKNOWN : ret;
 }
 
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 4abc5a76ec51..38ac776cba8a 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -1409,8 +1409,7 @@  EXPORT_SYMBOL_GPL(typec_set_pwr_opmode);
  */
 int typec_find_port_power_role(const char *name)
 {
-	return __match_string(typec_port_power_roles,
-			      ARRAY_SIZE(typec_port_power_roles), name);
+	return match_string(typec_port_power_roles, name);
 }
 EXPORT_SYMBOL_GPL(typec_find_port_power_role);
 
@@ -1424,7 +1423,7 @@  EXPORT_SYMBOL_GPL(typec_find_port_power_role);
  */
 int typec_find_power_role(const char *name)
 {
-	return __match_string(typec_roles, ARRAY_SIZE(typec_roles), name);
+	return match_string(typec_roles, name);
 }
 EXPORT_SYMBOL_GPL(typec_find_power_role);
 
@@ -1438,8 +1437,7 @@  EXPORT_SYMBOL_GPL(typec_find_power_role);
  */
 int typec_find_port_data_role(const char *name)
 {
-	return __match_string(typec_port_data_roles,
-			      ARRAY_SIZE(typec_port_data_roles), name);
+	return match_string(typec_port_data_roles, name);
 }
 EXPORT_SYMBOL_GPL(typec_find_port_data_role);
 
diff --git a/drivers/usb/typec/tps6598x.c b/drivers/usb/typec/tps6598x.c
index 0389e4391faf..0c4e47868590 100644
--- a/drivers/usb/typec/tps6598x.c
+++ b/drivers/usb/typec/tps6598x.c
@@ -423,7 +423,7 @@  static int tps6598x_check_mode(struct tps6598x *tps)
 	if (ret)
 		return ret;
 
-	switch (__match_string(modes, ARRAY_SIZE(modes), mode)) {
+	switch (match_string(modes, mode)) {
 	case TPS_MODE_APP:
 		return 0;
 	case TPS_MODE_BOOT:
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index b31585ecf48f..fe8283d3781b 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -637,9 +637,7 @@  static bool vfio_dev_whitelisted(struct device *dev, struct device_driver *drv)
 			return true;
 	}
 
-	return __match_string(vfio_driver_whitelist,
-			      ARRAY_SIZE(vfio_driver_whitelist),
-			      drv->name) >= 0;
+	return match_string(vfio_driver_whitelist, drv->name) >= 0;
 }
 
 /*
diff --git a/include/linux/string.h b/include/linux/string.h
index 531d04308ff9..07e9f89088df 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -194,6 +194,15 @@  static inline int strtobool(const char *s, bool *res)
 int __match_string(const char * const *array, size_t n, const char *string);
 int __sysfs_match_string(const char * const *array, size_t n, const char *s);
 
+/**
+ * match_string - matches given string in an array
+ * @_a: array of strings
+ * @_s: string to match with
+ *
+ * Helper for __match_string(). Calculates the size of @a automatically.
+ */
+#define match_string(_a, _s) __match_string(_a, ARRAY_SIZE(_a), _s)
+
 /**
  * sysfs_match_string - matches given string in an array
  * @_a: array of strings
diff --git a/sound/firewire/oxfw/oxfw.c b/sound/firewire/oxfw/oxfw.c
index 9ec5316f3bb5..433fc84c4f90 100644
--- a/sound/firewire/oxfw/oxfw.c
+++ b/sound/firewire/oxfw/oxfw.c
@@ -57,7 +57,7 @@  static bool detect_loud_models(struct fw_unit *unit)
 	if (err < 0)
 		return false;
 
-	return __match_string(models, ARRAY_SIZE(models), model) >= 0;
+	return match_string(models, model) >= 0;
 }
 
 static int name_card(struct snd_oxfw *oxfw)
diff --git a/sound/soc/codecs/max98088.c b/sound/soc/codecs/max98088.c
index 3ef743075bda..911ffe84c37e 100644
--- a/sound/soc/codecs/max98088.c
+++ b/sound/soc/codecs/max98088.c
@@ -1405,7 +1405,7 @@  static int max98088_get_channel(struct snd_soc_component *component, const char
 {
 	int ret;
 
-	ret = __match_string(eq_mode_name, ARRAY_SIZE(eq_mode_name), name);
+	ret = match_string(eq_mode_name, name);
 	if (ret < 0)
 		dev_err(component->dev, "Bad EQ channel name '%s'\n", name);
 	return ret;
diff --git a/sound/soc/codecs/max98095.c b/sound/soc/codecs/max98095.c
index cd69916d5dcb..d182d45d0c83 100644
--- a/sound/soc/codecs/max98095.c
+++ b/sound/soc/codecs/max98095.c
@@ -1636,7 +1636,7 @@  static int max98095_get_bq_channel(struct snd_soc_component *component,
 {
 	int ret;
 
-	ret = __match_string(bq_mode_name, ARRAY_SIZE(bq_mode_name), name);
+	ret = match_string(bq_mode_name, name);
 	if (ret < 0)
 		dev_err(component->dev, "Bad biquad channel name '%s'\n", name);
 	return ret;