Re: [PATCH 23/36] driver core: bus: mark the struct bus_type for sysfs callbacks as constant

[Harald Freudenberger <freude@linux.ibm.com>]

On 2023-03-13 19:29, Greg Kroah-Hartman wrote:
> struct bus_type should never be modified in a sysfs callback as there 
> is
> nothing in the structure to modify, and frankly, the structure is 
> almost
> never used in a sysfs callback, so mark it as constant to allow struct
> bus_type to be moved to read-only memory.
> 
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
> Cc: "K. Y. Srinivasan" <kys@microsoft.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: Alex Shi <alexs@kernel.org>
> Cc: Alexander Gordeev <agordeev@linux.ibm.com>
> Cc: Alexandre Bounine <alex.bou9@gmail.com>
> Cc: Alison Schofield <alison.schofield@intel.com>
> Cc: Ben Widawsky <bwidawsk@kernel.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Dexuan Cui <decui@microsoft.com>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Harald Freudenberger <freude@linux.ibm.com>
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Hu Haowen <src.res@email.cn>
> Cc: Ilya Dryomov <idryomov@gmail.com>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Cc: Iwona Winiarska <iwona.winiarska@intel.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Cc: Matt Porter <mporter@kernel.crashing.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Stuart Yoder <stuyoder@gmail.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Wei Liu <wei.liu@kernel.org>
> Cc: Yanteng Si <siyanteng@loongson.cn>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> Note, this is a patch that is a prepatory cleanup as part of a larger
> series of patches that is working on resolving some old driver core
> design mistakes.  It will build and apply cleanly on top of 6.3-rc2 on
> its own, but I'd prefer if I could take it through my driver-core tree
> so that the driver core changes can be taken through there for 6.4-rc1.
> 
>  Documentation/driver-api/driver-model/bus.rst |  4 +-
>  Documentation/filesystems/sysfs.rst           |  4 +-
>  .../translations/zh_CN/filesystems/sysfs.txt  |  4 +-
>  .../translations/zh_TW/filesystems/sysfs.txt  |  4 +-
>  arch/powerpc/platforms/pseries/ibmebus.c      |  4 +-
>  arch/powerpc/platforms/pseries/vio.c          |  8 ++--
>  drivers/ata/pata_parport/pata_parport.c       |  6 +--
>  drivers/base/bus.c                            |  8 ++--
>  drivers/block/rbd.c                           | 34 +++++++--------
>  drivers/bus/fsl-mc/fsl-mc-bus.c               |  6 +--
>  drivers/cxl/core/port.c                       |  2 +-
>  drivers/hv/vmbus_drv.c                        |  2 +-
>  drivers/net/netdevsim/bus.c                   |  4 +-
>  drivers/pci/pci-sysfs.c                       |  2 +-
>  drivers/pci/pci.c                             |  4 +-
>  drivers/peci/sysfs.c                          |  2 +-
>  drivers/rapidio/rio-sysfs.c                   |  2 +-
>  drivers/s390/crypto/ap_bus.c                  | 42 +++++++++----------
>  drivers/scsi/fcoe/fcoe_sysfs.c                |  8 ++--
>  drivers/scsi/fcoe/fcoe_transport.c            |  6 +--
>  include/linux/device/bus.h                    |  4 +-
>  include/scsi/libfcoe.h                        |  6 +--
>  22 files changed, 78 insertions(+), 88 deletions(-)
> 
> diff --git a/Documentation/driver-api/driver-model/bus.rst
> b/Documentation/driver-api/driver-model/bus.rst
> index 016b15a6e8ea..9709ab62a468 100644
> --- a/Documentation/driver-api/driver-model/bus.rst
> +++ b/Documentation/driver-api/driver-model/bus.rst
> @@ -125,8 +125,8 @@ Exporting Attributes
> 
>    struct bus_attribute {
>  	struct attribute	attr;
> -	ssize_t (*show)(struct bus_type *, char * buf);
> -	ssize_t (*store)(struct bus_type *, const char * buf, size_t count);
> +	ssize_t (*show)(const struct bus_type *, char * buf);
> +	ssize_t (*store)(const struct bus_type *, const char * buf, size_t 
> count);
>    };
> 
>  Bus drivers can export attributes using the BUS_ATTR_RW macro that 
> works
> diff --git a/Documentation/filesystems/sysfs.rst
> b/Documentation/filesystems/sysfs.rst
> index f8187d466b97..c32993bc83c7 100644
> --- a/Documentation/filesystems/sysfs.rst
> +++ b/Documentation/filesystems/sysfs.rst
> @@ -373,8 +373,8 @@ Structure::
> 
>      struct bus_attribute {
>  	    struct attribute        attr;
> -	    ssize_t (*show)(struct bus_type *, char * buf);
> -	    ssize_t (*store)(struct bus_type *, const char * buf, size_t 
> count);
> +	    ssize_t (*show)(const struct bus_type *, char * buf);
> +	    ssize_t (*store)(const struct bus_type *, const char * buf, 
> size_t count);
>      };
> 
>  Declaring::
> diff --git a/Documentation/translations/zh_CN/filesystems/sysfs.txt
> b/Documentation/translations/zh_CN/filesystems/sysfs.txt
> index 046cc1d52058..547062759e60 100644
> --- a/Documentation/translations/zh_CN/filesystems/sysfs.txt
> +++ b/Documentation/translations/zh_CN/filesystems/sysfs.txt
> @@ -329,8 +329,8 @@ void device_remove_file(struct device *dev, const
> struct device_attribute * attr
> 
>  struct bus_attribute {
>          struct attribute        attr;
> -        ssize_t (*show)(struct bus_type *, char * buf);
> -        ssize_t (*store)(struct bus_type *, const char * buf, size_t 
> count);
> +        ssize_t (*show)(const struct bus_type *, char * buf);
> +        ssize_t (*store)(const struct bus_type *, const char * buf,
> size_t count);
>  };
> 
>  声明:
> diff --git a/Documentation/translations/zh_TW/filesystems/sysfs.txt
> b/Documentation/translations/zh_TW/filesystems/sysfs.txt
> index acd677f19d4f..280824cc7e5d 100644
> --- a/Documentation/translations/zh_TW/filesystems/sysfs.txt
> +++ b/Documentation/translations/zh_TW/filesystems/sysfs.txt
> @@ -332,8 +332,8 @@ void device_remove_file(struct device *dev, const
> struct device_attribute * attr
> 
>  struct bus_attribute {
>          struct attribute        attr;
> -        ssize_t (*show)(struct bus_type *, char * buf);
> -        ssize_t (*store)(struct bus_type *, const char * buf, size_t 
> count);
> +        ssize_t (*show)(const struct bus_type *, char * buf);
> +        ssize_t (*store)(const struct bus_type *, const char * buf,
> size_t count);
>  };
> 
>  聲明:
> diff --git a/arch/powerpc/platforms/pseries/ibmebus.c
> b/arch/powerpc/platforms/pseries/ibmebus.c
> index bb9c18682783..44703f13985b 100644
> --- a/arch/powerpc/platforms/pseries/ibmebus.c
> +++ b/arch/powerpc/platforms/pseries/ibmebus.c
> @@ -267,7 +267,7 @@ static char *ibmebus_chomp(const char *in, size_t 
> count)
>  	return out;
>  }
> 
> -static ssize_t probe_store(struct bus_type *bus, const char *buf, 
> size_t count)
> +static ssize_t probe_store(const struct bus_type *bus, const char
> *buf, size_t count)
>  {
>  	struct device_node *dn = NULL;
>  	struct device *dev;
> @@ -305,7 +305,7 @@ static ssize_t probe_store(struct bus_type *bus,
> const char *buf, size_t count)
>  }
>  static BUS_ATTR_WO(probe);
> 
> -static ssize_t remove_store(struct bus_type *bus, const char *buf,
> size_t count)
> +static ssize_t remove_store(const struct bus_type *bus, const char
> *buf, size_t count)
>  {
>  	struct device *dev;
>  	char *path;
> diff --git a/arch/powerpc/platforms/pseries/vio.c
> b/arch/powerpc/platforms/pseries/vio.c
> index 770df9351aaa..bf7aff6390be 100644
> --- a/arch/powerpc/platforms/pseries/vio.c
> +++ b/arch/powerpc/platforms/pseries/vio.c
> @@ -1006,7 +1006,7 @@ ATTRIBUTE_GROUPS(vio_cmo_dev);
>  /* sysfs bus functions and data structures for CMO */
> 
>  #define viobus_cmo_rd_attr(name)                                       
>  \
> -static ssize_t cmo_bus_##name##_show(struct bus_type *bt, char *buf)   
>  \
> +static ssize_t cmo_bus_##name##_show(const struct bus_type *bt, char 
> *buf)    \
>  {                                                                      
>  \
>  	return sprintf(buf, "%lu\n", vio_cmo.name);                     \
>  }                                                                      
>  \
> @@ -1015,7 +1015,7 @@ static struct bus_attribute 
> bus_attr_cmo_bus_##name =			\
> 
>  #define viobus_cmo_pool_rd_attr(name, var)                             
>  \
>  static ssize_t                                                         
>  \
> -cmo_##name##_##var##_show(struct bus_type *bt, char *buf)              
>  \
> +cmo_##name##_##var##_show(const struct bus_type *bt, char *buf)        
>  \
>  {                                                                      
>  \
>  	return sprintf(buf, "%lu\n", vio_cmo.name.var);                 \
>  }                                                                      
>  \
> @@ -1030,12 +1030,12 @@ viobus_cmo_pool_rd_attr(reserve, size);
>  viobus_cmo_pool_rd_attr(excess, size);
>  viobus_cmo_pool_rd_attr(excess, free);
> 
> -static ssize_t cmo_high_show(struct bus_type *bt, char *buf)
> +static ssize_t cmo_high_show(const struct bus_type *bt, char *buf)
>  {
>  	return sprintf(buf, "%lu\n", vio_cmo.high);
>  }
> 
> -static ssize_t cmo_high_store(struct bus_type *bt, const char *buf,
> +static ssize_t cmo_high_store(const struct bus_type *bt, const char 
> *buf,
>  			      size_t count)
>  {
>  	unsigned long flags;
> diff --git a/drivers/ata/pata_parport/pata_parport.c
> b/drivers/ata/pata_parport/pata_parport.c
> index 294a266a0dda..64d1bde26940 100644
> --- a/drivers/ata/pata_parport/pata_parport.c
> +++ b/drivers/ata/pata_parport/pata_parport.c
> @@ -554,8 +554,7 @@ void pata_parport_unregister_driver(struct 
> pi_protocol *pr)
>  }
>  EXPORT_SYMBOL_GPL(pata_parport_unregister_driver);
> 
> -static ssize_t new_device_store(struct bus_type *bus, const char *buf,
> -				size_t count)
> +static ssize_t new_device_store(const struct bus_type *bus, const
> char *buf, size_t count)
>  {
>  	char port[12] = "auto";
>  	char protocol[8] = "auto";
> @@ -630,8 +629,7 @@ static void pi_remove_one(struct device *dev)
>  	/* pata_parport_dev_release will do kfree(pi) */
>  }
> 
> -static ssize_t delete_device_store(struct bus_type *bus, const char 
> *buf,
> -				   size_t count)
> +static ssize_t delete_device_store(const struct bus_type *bus, const
> char *buf, size_t count)
>  {
>  	struct device *dev;
> 
> diff --git a/drivers/base/bus.c b/drivers/base/bus.c
> index 91a6b6b1fc49..819ab745fa9f 100644
> --- a/drivers/base/bus.c
> +++ b/drivers/base/bus.c
> @@ -274,7 +274,7 @@ static ssize_t bind_store(struct device_driver
> *drv, const char *buf,
>  }
>  static DRIVER_ATTR_IGNORE_LOCKDEP(bind, 0200, NULL, bind_store);
> 
> -static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf)
> +static ssize_t drivers_autoprobe_show(const struct bus_type *bus, char 
> *buf)
>  {
>  	struct subsys_private *sp = bus_to_subsys(bus);
>  	int ret;
> @@ -287,7 +287,7 @@ static ssize_t drivers_autoprobe_show(struct
> bus_type *bus, char *buf)
>  	return ret;
>  }
> 
> -static ssize_t drivers_autoprobe_store(struct bus_type *bus,
> +static ssize_t drivers_autoprobe_store(const struct bus_type *bus,
>  				       const char *buf, size_t count)
>  {
>  	struct subsys_private *sp = bus_to_subsys(bus);
> @@ -304,7 +304,7 @@ static ssize_t drivers_autoprobe_store(struct 
> bus_type *bus,
>  	return count;
>  }
> 
> -static ssize_t drivers_probe_store(struct bus_type *bus,
> +static ssize_t drivers_probe_store(const struct bus_type *bus,
>  				   const char *buf, size_t count)
>  {
>  	struct device *dev;
> @@ -808,7 +808,7 @@ static void klist_devices_put(struct klist_node *n)
>  	put_device(dev);
>  }
> 
> -static ssize_t bus_uevent_store(struct bus_type *bus,
> +static ssize_t bus_uevent_store(const struct bus_type *bus,
>  				const char *buf, size_t count)
>  {
>  	struct subsys_private *sp = bus_to_subsys(bus);
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 5cb008b9700a..84ad3b17956f 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -491,12 +491,12 @@ static bool single_major = true;
>  module_param(single_major, bool, 0444);
>  MODULE_PARM_DESC(single_major, "Use a single major number for all rbd
> devices (default: true)");
> 
> -static ssize_t add_store(struct bus_type *bus, const char *buf, size_t 
> count);
> -static ssize_t remove_store(struct bus_type *bus, const char *buf,
> +static ssize_t add_store(const struct bus_type *bus, const char *buf,
> size_t count);
> +static ssize_t remove_store(const struct bus_type *bus, const char 
> *buf,
>  			    size_t count);
> -static ssize_t add_single_major_store(struct bus_type *bus, const char 
> *buf,
> +static ssize_t add_single_major_store(const struct bus_type *bus,
> const char *buf,
>  				      size_t count);
> -static ssize_t remove_single_major_store(struct bus_type *bus, const 
> char *buf,
> +static ssize_t remove_single_major_store(const struct bus_type *bus,
> const char *buf,
>  					 size_t count);
>  static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth);
> 
> @@ -538,7 +538,7 @@ static bool rbd_is_lock_owner(struct rbd_device 
> *rbd_dev)
>  	return is_lock_owner;
>  }
> 
> -static ssize_t supported_features_show(struct bus_type *bus, char 
> *buf)
> +static ssize_t supported_features_show(const struct bus_type *bus, 
> char *buf)
>  {
>  	return sprintf(buf, "0x%llx\n", RBD_FEATURES_SUPPORTED);
>  }
> @@ -6967,9 +6967,7 @@ static int rbd_dev_image_probe(struct rbd_device
> *rbd_dev, int depth)
>  	return ret;
>  }
> 
> -static ssize_t do_rbd_add(struct bus_type *bus,
> -			  const char *buf,
> -			  size_t count)
> +static ssize_t do_rbd_add(const char *buf, size_t count)
>  {
>  	struct rbd_device *rbd_dev = NULL;
>  	struct ceph_options *ceph_opts = NULL;
> @@ -7081,18 +7079,18 @@ static ssize_t do_rbd_add(struct bus_type *bus,
>  	goto out;
>  }
> 
> -static ssize_t add_store(struct bus_type *bus, const char *buf, size_t 
> count)
> +static ssize_t add_store(const struct bus_type *bus, const char *buf,
> size_t count)
>  {
>  	if (single_major)
>  		return -EINVAL;
> 
> -	return do_rbd_add(bus, buf, count);
> +	return do_rbd_add(buf, count);
>  }
> 
> -static ssize_t add_single_major_store(struct bus_type *bus, const char 
> *buf,
> +static ssize_t add_single_major_store(const struct bus_type *bus,
> const char *buf,
>  				      size_t count)
>  {
> -	return do_rbd_add(bus, buf, count);
> +	return do_rbd_add(buf, count);
>  }
> 
>  static void rbd_dev_remove_parent(struct rbd_device *rbd_dev)
> @@ -7122,9 +7120,7 @@ static void rbd_dev_remove_parent(struct
> rbd_device *rbd_dev)
>  	}
>  }
> 
> -static ssize_t do_rbd_remove(struct bus_type *bus,
> -			     const char *buf,
> -			     size_t count)
> +static ssize_t do_rbd_remove(const char *buf, size_t count)
>  {
>  	struct rbd_device *rbd_dev = NULL;
>  	struct list_head *tmp;
> @@ -7196,18 +7192,18 @@ static ssize_t do_rbd_remove(struct bus_type 
> *bus,
>  	return count;
>  }
> 
> -static ssize_t remove_store(struct bus_type *bus, const char *buf,
> size_t count)
> +static ssize_t remove_store(const struct bus_type *bus, const char
> *buf, size_t count)
>  {
>  	if (single_major)
>  		return -EINVAL;
> 
> -	return do_rbd_remove(bus, buf, count);
> +	return do_rbd_remove(buf, count);
>  }
> 
> -static ssize_t remove_single_major_store(struct bus_type *bus, const 
> char *buf,
> +static ssize_t remove_single_major_store(const struct bus_type *bus,
> const char *buf,
>  					 size_t count)
>  {
> -	return do_rbd_remove(bus, buf, count);
> +	return do_rbd_remove(buf, count);
>  }
> 
>  /*
> diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c 
> b/drivers/bus/fsl-mc/fsl-mc-bus.c
> index 36cb091a33b4..653e2d4c116f 100644
> --- a/drivers/bus/fsl-mc/fsl-mc-bus.c
> +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
> @@ -231,7 +231,7 @@ static int scan_fsl_mc_bus(struct device *dev, void 
> *data)
>  	return 0;
>  }
> 
> -static ssize_t rescan_store(struct bus_type *bus,
> +static ssize_t rescan_store(const struct bus_type *bus,
>  			    const char *buf, size_t count)
>  {
>  	unsigned long val;
> @@ -284,7 +284,7 @@ static int fsl_mc_bus_get_autorescan(struct device
> *dev, void *data)
>  	return 0;
>  }
> 
> -static ssize_t autorescan_store(struct bus_type *bus,
> +static ssize_t autorescan_store(const struct bus_type *bus,
>  				const char *buf, size_t count)
>  {
>  	bus_for_each_dev(bus, NULL, (void *)buf, fsl_mc_bus_set_autorescan);
> @@ -292,7 +292,7 @@ static ssize_t autorescan_store(struct bus_type 
> *bus,
>  	return count;
>  }
> 
> -static ssize_t autorescan_show(struct bus_type *bus, char *buf)
> +static ssize_t autorescan_show(const struct bus_type *bus, char *buf)
>  {
>  	bus_for_each_dev(bus, NULL, (void *)buf, fsl_mc_bus_get_autorescan);
>  	return strlen(buf);
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 8ee6b6e2e2a4..66333cd6248e 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -1927,7 +1927,7 @@ bool schedule_cxl_memdev_detach(struct cxl_memdev 
> *cxlmd)
>  EXPORT_SYMBOL_NS_GPL(schedule_cxl_memdev_detach, CXL);
> 
>  /* for user tooling to ensure port disable work has completed */
> -static ssize_t flush_store(struct bus_type *bus, const char *buf, 
> size_t count)
> +static ssize_t flush_store(const struct bus_type *bus, const char
> *buf, size_t count)
>  {
>  	if (sysfs_streq(buf, "1")) {
>  		flush_workqueue(cxl_bus_wq);
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index d24dd65b33d4..513adba09f56 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -684,7 +684,7 @@ static const struct attribute_group vmbus_dev_group 
> = {
>  __ATTRIBUTE_GROUPS(vmbus_dev);
> 
>  /* Set up the attribute for /sys/bus/vmbus/hibernation */
> -static ssize_t hibernation_show(struct bus_type *bus, char *buf)
> +static ssize_t hibernation_show(const struct bus_type *bus, char *buf)
>  {
>  	return sprintf(buf, "%d\n", !!hv_is_hibernation_supported());
>  }
> diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c
> index 0052968e881e..0787ad252dd9 100644
> --- a/drivers/net/netdevsim/bus.c
> +++ b/drivers/net/netdevsim/bus.c
> @@ -132,7 +132,7 @@ static struct nsim_bus_dev *
>  nsim_bus_dev_new(unsigned int id, unsigned int port_count, unsigned
> int num_queues);
> 
>  static ssize_t
> -new_device_store(struct bus_type *bus, const char *buf, size_t count)
> +new_device_store(const struct bus_type *bus, const char *buf, size_t 
> count)
>  {
>  	unsigned int id, port_count, num_queues;
>  	struct nsim_bus_dev *nsim_bus_dev;
> @@ -186,7 +186,7 @@ static BUS_ATTR_WO(new_device);
>  static void nsim_bus_dev_del(struct nsim_bus_dev *nsim_bus_dev);
> 
>  static ssize_t
> -del_device_store(struct bus_type *bus, const char *buf, size_t count)
> +del_device_store(const struct bus_type *bus, const char *buf, size_t 
> count)
>  {
>  	struct nsim_bus_dev *nsim_bus_dev, *tmp;
>  	unsigned int id;
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index dd0d9d9bc509..ab32a91f287b 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -428,7 +428,7 @@ static ssize_t msi_bus_store(struct device *dev,
> struct device_attribute *attr,
>  }
>  static DEVICE_ATTR_RW(msi_bus);
> 
> -static ssize_t rescan_store(struct bus_type *bus, const char *buf,
> size_t count)
> +static ssize_t rescan_store(const struct bus_type *bus, const char
> *buf, size_t count)
>  {
>  	unsigned long val;
>  	struct pci_bus *b = NULL;
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7a67611dc5f4..45c3bb039f21 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -6679,7 +6679,7 @@ void pci_reassigndev_resource_alignment(struct
> pci_dev *dev)
>  	}
>  }
> 
> -static ssize_t resource_alignment_show(struct bus_type *bus, char 
> *buf)
> +static ssize_t resource_alignment_show(const struct bus_type *bus, 
> char *buf)
>  {
>  	size_t count = 0;
> 
> @@ -6691,7 +6691,7 @@ static ssize_t resource_alignment_show(struct
> bus_type *bus, char *buf)
>  	return count;
>  }
> 
> -static ssize_t resource_alignment_store(struct bus_type *bus,
> +static ssize_t resource_alignment_store(const struct bus_type *bus,
>  					const char *buf, size_t count)
>  {
>  	char *param, *old, *end;
> diff --git a/drivers/peci/sysfs.c b/drivers/peci/sysfs.c
> index db9ef05776e3..c04244075794 100644
> --- a/drivers/peci/sysfs.c
> +++ b/drivers/peci/sysfs.c
> @@ -15,7 +15,7 @@ static int rescan_controller(struct device *dev, void 
> *data)
>  	return peci_controller_scan_devices(to_peci_controller(dev));
>  }
> 
> -static ssize_t rescan_store(struct bus_type *bus, const char *buf,
> size_t count)
> +static ssize_t rescan_store(const struct bus_type *bus, const char
> *buf, size_t count)
>  {
>  	bool res;
>  	int ret;
> diff --git a/drivers/rapidio/rio-sysfs.c b/drivers/rapidio/rio-sysfs.c
> index f7679602498e..90d391210533 100644
> --- a/drivers/rapidio/rio-sysfs.c
> +++ b/drivers/rapidio/rio-sysfs.c
> @@ -286,7 +286,7 @@ const struct attribute_group *rio_dev_groups[] = {
>  	NULL,
>  };
> 
> -static ssize_t scan_store(struct bus_type *bus, const char *buf, 
> size_t count)
> +static ssize_t scan_store(const struct bus_type *bus, const char
> *buf, size_t count)
>  {
>  	long val;
>  	int rc;
> diff --git a/drivers/s390/crypto/ap_bus.c 
> b/drivers/s390/crypto/ap_bus.c
> index f4cc1720156f..5a99e0b18289 100644
> --- a/drivers/s390/crypto/ap_bus.c
> +++ b/drivers/s390/crypto/ap_bus.c
> @@ -1166,12 +1166,12 @@ EXPORT_SYMBOL(ap_parse_mask_str);
>   * AP bus attributes.
>   */
> 
> -static ssize_t ap_domain_show(struct bus_type *bus, char *buf)
> +static ssize_t ap_domain_show(const struct bus_type *bus, char *buf)
>  {
>  	return scnprintf(buf, PAGE_SIZE, "%d\n", ap_domain_index);
>  }
> 
> -static ssize_t ap_domain_store(struct bus_type *bus,
> +static ssize_t ap_domain_store(const struct bus_type *bus,
>  			       const char *buf, size_t count)
>  {
>  	int domain;
> @@ -1193,7 +1193,7 @@ static ssize_t ap_domain_store(struct bus_type 
> *bus,
> 
>  static BUS_ATTR_RW(ap_domain);
> 
> -static ssize_t ap_control_domain_mask_show(struct bus_type *bus, char 
> *buf)
> +static ssize_t ap_control_domain_mask_show(const struct bus_type
> *bus, char *buf)
>  {
>  	if (!ap_qci_info)	/* QCI not supported */
>  		return scnprintf(buf, PAGE_SIZE, "not supported\n");
> @@ -1208,7 +1208,7 @@ static ssize_t
> ap_control_domain_mask_show(struct bus_type *bus, char *buf)
> 
>  static BUS_ATTR_RO(ap_control_domain_mask);
> 
> -static ssize_t ap_usage_domain_mask_show(struct bus_type *bus, char 
> *buf)
> +static ssize_t ap_usage_domain_mask_show(const struct bus_type *bus, 
> char *buf)
>  {
>  	if (!ap_qci_info)	/* QCI not supported */
>  		return scnprintf(buf, PAGE_SIZE, "not supported\n");
> @@ -1223,7 +1223,7 @@ static ssize_t ap_usage_domain_mask_show(struct
> bus_type *bus, char *buf)
> 
>  static BUS_ATTR_RO(ap_usage_domain_mask);
> 
> -static ssize_t ap_adapter_mask_show(struct bus_type *bus, char *buf)
> +static ssize_t ap_adapter_mask_show(const struct bus_type *bus, char 
> *buf)
>  {
>  	if (!ap_qci_info)	/* QCI not supported */
>  		return scnprintf(buf, PAGE_SIZE, "not supported\n");
> @@ -1238,7 +1238,7 @@ static ssize_t ap_adapter_mask_show(struct
> bus_type *bus, char *buf)
> 
>  static BUS_ATTR_RO(ap_adapter_mask);
> 
> -static ssize_t ap_interrupts_show(struct bus_type *bus, char *buf)
> +static ssize_t ap_interrupts_show(const struct bus_type *bus, char 
> *buf)
>  {
>  	return scnprintf(buf, PAGE_SIZE, "%d\n",
>  			 ap_irq_flag ? 1 : 0);
> @@ -1246,12 +1246,12 @@ static ssize_t ap_interrupts_show(struct
> bus_type *bus, char *buf)
> 
>  static BUS_ATTR_RO(ap_interrupts);
> 
> -static ssize_t config_time_show(struct bus_type *bus, char *buf)
> +static ssize_t config_time_show(const struct bus_type *bus, char *buf)
>  {
>  	return scnprintf(buf, PAGE_SIZE, "%d\n", ap_config_time);
>  }
> 
> -static ssize_t config_time_store(struct bus_type *bus,
> +static ssize_t config_time_store(const struct bus_type *bus,
>  				 const char *buf, size_t count)
>  {
>  	int time;
> @@ -1265,12 +1265,12 @@ static ssize_t config_time_store(struct 
> bus_type *bus,
> 
>  static BUS_ATTR_RW(config_time);
> 
> -static ssize_t poll_thread_show(struct bus_type *bus, char *buf)
> +static ssize_t poll_thread_show(const struct bus_type *bus, char *buf)
>  {
>  	return scnprintf(buf, PAGE_SIZE, "%d\n", ap_poll_kthread ? 1 : 0);
>  }
> 
> -static ssize_t poll_thread_store(struct bus_type *bus,
> +static ssize_t poll_thread_store(const struct bus_type *bus,
>  				 const char *buf, size_t count)
>  {
>  	int flag, rc;
> @@ -1289,12 +1289,12 @@ static ssize_t poll_thread_store(struct 
> bus_type *bus,
> 
>  static BUS_ATTR_RW(poll_thread);
> 
> -static ssize_t poll_timeout_show(struct bus_type *bus, char *buf)
> +static ssize_t poll_timeout_show(const struct bus_type *bus, char 
> *buf)
>  {
>  	return scnprintf(buf, PAGE_SIZE, "%llu\n", poll_timeout);
>  }
> 
> -static ssize_t poll_timeout_store(struct bus_type *bus, const char 
> *buf,
> +static ssize_t poll_timeout_store(const struct bus_type *bus, const 
> char *buf,
>  				  size_t count)
>  {
>  	unsigned long long time;
> @@ -1318,21 +1318,21 @@ static ssize_t poll_timeout_store(struct
> bus_type *bus, const char *buf,
> 
>  static BUS_ATTR_RW(poll_timeout);
> 
> -static ssize_t ap_max_domain_id_show(struct bus_type *bus, char *buf)
> +static ssize_t ap_max_domain_id_show(const struct bus_type *bus, char 
> *buf)
>  {
>  	return scnprintf(buf, PAGE_SIZE, "%d\n", ap_max_domain_id);
>  }
> 
>  static BUS_ATTR_RO(ap_max_domain_id);
> 
> -static ssize_t ap_max_adapter_id_show(struct bus_type *bus, char *buf)
> +static ssize_t ap_max_adapter_id_show(const struct bus_type *bus, char 
> *buf)
>  {
>  	return scnprintf(buf, PAGE_SIZE, "%d\n", ap_max_adapter_id);
>  }
> 
>  static BUS_ATTR_RO(ap_max_adapter_id);
> 
> -static ssize_t apmask_show(struct bus_type *bus, char *buf)
> +static ssize_t apmask_show(const struct bus_type *bus, char *buf)
>  {
>  	int rc;
> 
> @@ -1393,7 +1393,7 @@ static int apmask_commit(unsigned long *newapm)
>  	return 0;
>  }
> 
> -static ssize_t apmask_store(struct bus_type *bus, const char *buf,
> +static ssize_t apmask_store(const struct bus_type *bus, const char 
> *buf,
>  			    size_t count)
>  {
>  	int rc, changes = 0;
> @@ -1425,7 +1425,7 @@ static ssize_t apmask_store(struct bus_type
> *bus, const char *buf,
> 
>  static BUS_ATTR_RW(apmask);
> 
> -static ssize_t aqmask_show(struct bus_type *bus, char *buf)
> +static ssize_t aqmask_show(const struct bus_type *bus, char *buf)
>  {
>  	int rc;
> 
> @@ -1486,7 +1486,7 @@ static int aqmask_commit(unsigned long *newaqm)
>  	return 0;
>  }
> 
> -static ssize_t aqmask_store(struct bus_type *bus, const char *buf,
> +static ssize_t aqmask_store(const struct bus_type *bus, const char 
> *buf,
>  			    size_t count)
>  {
>  	int rc, changes = 0;
> @@ -1518,13 +1518,13 @@ static ssize_t aqmask_store(struct bus_type
> *bus, const char *buf,
> 
>  static BUS_ATTR_RW(aqmask);
> 
> -static ssize_t scans_show(struct bus_type *bus, char *buf)
> +static ssize_t scans_show(const struct bus_type *bus, char *buf)
>  {
>  	return scnprintf(buf, PAGE_SIZE, "%llu\n",
>  			 atomic64_read(&ap_scan_bus_count));
>  }
> 
> -static ssize_t scans_store(struct bus_type *bus, const char *buf,
> +static ssize_t scans_store(const struct bus_type *bus, const char 
> *buf,
>  			   size_t count)
>  {
>  	AP_DBF_INFO("%s force AP bus rescan\n", __func__);
> @@ -1536,7 +1536,7 @@ static ssize_t scans_store(struct bus_type *bus,
> const char *buf,
> 
>  static BUS_ATTR_RW(scans);
> 
> -static ssize_t bindings_show(struct bus_type *bus, char *buf)
> +static ssize_t bindings_show(const struct bus_type *bus, char *buf)
>  {
>  	int rc;
>  	unsigned int apqns, n;
> diff --git a/drivers/scsi/fcoe/fcoe_sysfs.c 
> b/drivers/scsi/fcoe/fcoe_sysfs.c
> index 6260aa5ea6af..e17957f8085c 100644
> --- a/drivers/scsi/fcoe/fcoe_sysfs.c
> +++ b/drivers/scsi/fcoe/fcoe_sysfs.c
> @@ -659,17 +659,17 @@ static const struct device_type 
> fcoe_fcf_device_type = {
>  	.release = fcoe_fcf_device_release,
>  };
> 
> -static ssize_t ctlr_create_store(struct bus_type *bus, const char 
> *buf,
> +static ssize_t ctlr_create_store(const struct bus_type *bus, const 
> char *buf,
>  				 size_t count)
>  {
> -	return fcoe_ctlr_create_store(bus, buf, count);
> +	return fcoe_ctlr_create_store(buf, count);
>  }
>  static BUS_ATTR_WO(ctlr_create);
> 
> -static ssize_t ctlr_destroy_store(struct bus_type *bus, const char 
> *buf,
> +static ssize_t ctlr_destroy_store(const struct bus_type *bus, const 
> char *buf,
>  				  size_t count)
>  {
> -	return fcoe_ctlr_destroy_store(bus, buf, count);
> +	return fcoe_ctlr_destroy_store(buf, count);
>  }
>  static BUS_ATTR_WO(ctlr_destroy);
> 
> diff --git a/drivers/scsi/fcoe/fcoe_transport.c
> b/drivers/scsi/fcoe/fcoe_transport.c
> index 62341c6353a7..46b0bf237be1 100644
> --- a/drivers/scsi/fcoe/fcoe_transport.c
> +++ b/drivers/scsi/fcoe/fcoe_transport.c
> @@ -745,8 +745,7 @@ static int libfcoe_device_notification(struct
> notifier_block *notifier,
>  	return NOTIFY_OK;
>  }
> 
> -ssize_t fcoe_ctlr_create_store(struct bus_type *bus,
> -			       const char *buf, size_t count)
> +ssize_t fcoe_ctlr_create_store(const char *buf, size_t count)
>  {
>  	struct net_device *netdev = NULL;
>  	struct fcoe_transport *ft = NULL;
> @@ -808,8 +807,7 @@ ssize_t fcoe_ctlr_create_store(struct bus_type 
> *bus,
>  	return count;
>  }
> 
> -ssize_t fcoe_ctlr_destroy_store(struct bus_type *bus,
> -				const char *buf, size_t count)
> +ssize_t fcoe_ctlr_destroy_store(const char *buf, size_t count)
>  {
>  	int rc = -ENODEV;
>  	struct net_device *netdev = NULL;
> diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h
> index c258e8770285..78c875386c06 100644
> --- a/include/linux/device/bus.h
> +++ b/include/linux/device/bus.h
> @@ -118,8 +118,8 @@ extern int __must_check bus_rescan_devices(struct
> bus_type *bus);
> 
>  struct bus_attribute {
>  	struct attribute	attr;
> -	ssize_t (*show)(struct bus_type *bus, char *buf);
> -	ssize_t (*store)(struct bus_type *bus, const char *buf, size_t 
> count);
> +	ssize_t (*show)(const struct bus_type *bus, char *buf);
> +	ssize_t (*store)(const struct bus_type *bus, const char *buf, size_t 
> count);
>  };
> 
>  #define BUS_ATTR_RW(_name) \
> diff --git a/include/scsi/libfcoe.h b/include/scsi/libfcoe.h
> index 279782156373..8300ef1a982e 100644
> --- a/include/scsi/libfcoe.h
> +++ b/include/scsi/libfcoe.h
> @@ -397,10 +397,8 @@ int fcoe_transport_attach(struct fcoe_transport 
> *ft);
>  int fcoe_transport_detach(struct fcoe_transport *ft);
> 
>  /* sysfs store handler for ctrl_control interface */
> -ssize_t fcoe_ctlr_create_store(struct bus_type *bus,
> -			       const char *buf, size_t count);
> -ssize_t fcoe_ctlr_destroy_store(struct bus_type *bus,
> -				const char *buf, size_t count);
> +ssize_t fcoe_ctlr_create_store(const char *buf, size_t count);
> +ssize_t fcoe_ctlr_destroy_store(const char *buf, size_t count);
> 
>  #endif /* _LIBFCOE_H */

For the ap_bus.c part: Reviewed-by: Harald Freudenberger 
<freude@linux.ibm.com>