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Date:   Mon, 9 May 2022 07:36:41 -0400
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Subject: Re: [PATCH] kernel/drivers: Remove redundant driver match function
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To:     lizhe <sensor1010@163.com>, lee.jones@linaro.org,
        fthain@linux-m68k.org, pasic@linux.ibm.com, jjherne@linux.ibm.com,
        freude@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com,
        agordeev@linux.ibm.com, borntraeger@linux.ibm.com,
        svens@linux.ibm.com, jejb@linux.ibm.com,
        martin.petersen@oracle.com, zbr@ioremap.net, perex@perex.cz,
        tiwai@suse.com, bvanassche@acm.org, dan.j.williams@intel.com,
        srinivas.kandagatla@linaro.org, wens@csie.org,
        colin.king@intel.com, u.kleine-koenig@pengutronix.de, hare@suse.de
Cc:     linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
        linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org,
        target-devel@vger.kernel.org, alsa-devel@alsa-project.org
References: <20220506045952.136290-1-sensor1010@163.com>
From:   Tony Krowiak <akrowiak@linux.ibm.com>
In-Reply-To: <20220506045952.136290-1-sensor1010@163.com>
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For the drivers/s390/crypto/vfio_ap_drv.c device driver:
Reviewed-by: Tony Krowiak <akrowiak@stny.rr.com>

On 5/6/22 12:59 AM, lizhe wrote:
> If there is no driver match function, the driver core assumes that each
> candidate pair (driver, device) matches, see driver_match_device().
>
> Signed-off-by: lizhe <sensor1010@163.com>
> ---
>   drivers/mfd/mcp-core.c             |  6 ------
>   drivers/nubus/bus.c                |  6 ------
>   drivers/s390/crypto/vfio_ap_drv.c  |  6 ------
>   drivers/scsi/scsi_debug.c          |  7 -------
>   drivers/target/loopback/tcm_loop.c |  7 -------
>   drivers/w1/w1.c                    |  6 ------
>   sound/ac97_bus.c                   | 11 -----------
>   7 files changed, 49 deletions(-)
>
> diff --git a/drivers/mfd/mcp-core.c b/drivers/mfd/mcp-core.c
> index 2fa592c37c6f..281a9369f2b3 100644
> --- a/drivers/mfd/mcp-core.c
> +++ b/drivers/mfd/mcp-core.c
> @@ -20,11 +20,6 @@
>   #define to_mcp(d)		container_of(d, struct mcp, attached_device)
>   #define to_mcp_driver(d)	container_of(d, struct mcp_driver, drv)
>   
> -static int mcp_bus_match(struct device *dev, struct device_driver *drv)
> -{
> -	return 1;
> -}
> -
>   static int mcp_bus_probe(struct device *dev)
>   {
>   	struct mcp *mcp = to_mcp(dev);
> @@ -43,7 +38,6 @@ static void mcp_bus_remove(struct device *dev)
>   
>   static struct bus_type mcp_bus_type = {
>   	.name		= "mcp",
> -	.match		= mcp_bus_match,
>   	.probe		= mcp_bus_probe,
>   	.remove		= mcp_bus_remove,
>   };
> diff --git a/drivers/nubus/bus.c b/drivers/nubus/bus.c
> index 17fad660032c..72921e4f35f6 100644
> --- a/drivers/nubus/bus.c
> +++ b/drivers/nubus/bus.c
> @@ -14,11 +14,6 @@
>   #define to_nubus_board(d)       container_of(d, struct nubus_board, dev)
>   #define to_nubus_driver(d)      container_of(d, struct nubus_driver, driver)
>   
> -static int nubus_bus_match(struct device *dev, struct device_driver *driver)
> -{
> -	return 1;
> -}
> -
>   static int nubus_device_probe(struct device *dev)
>   {
>   	struct nubus_driver *ndrv = to_nubus_driver(dev->driver);
> @@ -39,7 +34,6 @@ static void nubus_device_remove(struct device *dev)
>   
>   struct bus_type nubus_bus_type = {
>   	.name		= "nubus",
> -	.match		= nubus_bus_match,
>   	.probe		= nubus_device_probe,
>   	.remove		= nubus_device_remove,
>   };
> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index 29ebd54f8919..0a662c451f2a 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -172,14 +172,8 @@ static void vfio_ap_matrix_dev_release(struct device *dev)
>   	kfree(matrix_dev);
>   }
>   
> -static int matrix_bus_match(struct device *dev, struct device_driver *drv)
> -{
> -	return 1;
> -}
> -
>   static struct bus_type matrix_bus = {
>   	.name = "matrix",
> -	.match = &matrix_bus_match,
>   };
>   
>   static struct device_driver matrix_driver = {
> diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
> index 592a290e6cfa..8107489b36e8 100644
> --- a/drivers/scsi/scsi_debug.c
> +++ b/drivers/scsi/scsi_debug.c
> @@ -7844,15 +7844,8 @@ static void sdebug_driver_remove(struct device *dev)
>   	scsi_host_put(sdbg_host->shost);
>   }
>   
> -static int pseudo_lld_bus_match(struct device *dev,
> -				struct device_driver *dev_driver)
> -{
> -	return 1;
> -}
> -
>   static struct bus_type pseudo_lld_bus = {
>   	.name = "pseudo",
> -	.match = pseudo_lld_bus_match,
>   	.probe = sdebug_driver_probe,
>   	.remove = sdebug_driver_remove,
>   	.drv_groups = sdebug_drv_groups,
> diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
> index 4407b56aa6d1..eeb63deff94f 100644
> --- a/drivers/target/loopback/tcm_loop.c
> +++ b/drivers/target/loopback/tcm_loop.c
> @@ -83,15 +83,8 @@ static int tcm_loop_show_info(struct seq_file *m, struct Scsi_Host *host)
>   static int tcm_loop_driver_probe(struct device *);
>   static void tcm_loop_driver_remove(struct device *);
>   
> -static int pseudo_lld_bus_match(struct device *dev,
> -				struct device_driver *dev_driver)
> -{
> -	return 1;
> -}
> -
>   static struct bus_type tcm_loop_lld_bus = {
>   	.name			= "tcm_loop_bus",
> -	.match			= pseudo_lld_bus_match,
>   	.probe			= tcm_loop_driver_probe,
>   	.remove			= tcm_loop_driver_remove,
>   };
> diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
> index f2ae2e563dc5..a6ecfa1b3417 100644
> --- a/drivers/w1/w1.c
> +++ b/drivers/w1/w1.c
> @@ -58,11 +58,6 @@ MODULE_PARM_DESC(slave_ttl,
>   DEFINE_MUTEX(w1_mlock);
>   LIST_HEAD(w1_masters);
>   
> -static int w1_master_match(struct device *dev, struct device_driver *drv)
> -{
> -	return 1;
> -}
> -
>   static int w1_master_probe(struct device *dev)
>   {
>   	return -ENODEV;
> @@ -174,7 +169,6 @@ static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
>   
>   static struct bus_type w1_bus_type = {
>   	.name = "w1",
> -	.match = w1_master_match,
>   	.uevent = w1_uevent,
>   };
>   
> diff --git a/sound/ac97_bus.c b/sound/ac97_bus.c
> index b4685c53ff11..c7aee8c42c55 100644
> --- a/sound/ac97_bus.c
> +++ b/sound/ac97_bus.c
> @@ -75,19 +75,8 @@ int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
>   }
>   EXPORT_SYMBOL_GPL(snd_ac97_reset);
>   
> -/*
> - * Let drivers decide whether they want to support given codec from their
> - * probe method. Drivers have direct access to the struct snd_ac97
> - * structure and may  decide based on the id field amongst other things.
> - */
> -static int ac97_bus_match(struct device *dev, struct device_driver *drv)
> -{
> -	return 1;
> -}
> -
>   struct bus_type ac97_bus_type = {
>   	.name		= "ac97",
> -	.match		= ac97_bus_match,
>   };
>   
>   static int __init ac97_bus_init(void)