Re: [PATCH 11/14] vfio/mdev: consolidate all the name sysfs into the core code

[Eric Farman <farman@linux.ibm.com>]

On Fri, 2022-09-23 at 11:26 +0200, Christoph Hellwig wrote:
> Every driver just emits a static string, simply add a field to the
> mdev_type for the driver to fill out or fall back to the sysfs name
> and
> provide a standard sysfs show function.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>

Reviewed-by: Eric Farman <farman@linux.ibm.com>

> ---
>  .../driver-api/vfio-mediated-device.rst       |  2 +-
>  drivers/gpu/drm/i915/gvt/kvmgt.c              |  8 -------
>  drivers/s390/cio/vfio_ccw_drv.c               |  1 +
>  drivers/s390/cio/vfio_ccw_ops.c               |  8 -------
>  drivers/s390/crypto/vfio_ap_ops.c             | 10 +--------
>  drivers/vfio/mdev/mdev_sysfs.c                | 10 +++++++++
>  include/linux/mdev.h                          |  1 +
>  samples/vfio-mdev/mbochs.c                    | 20 ++++-------------
> -
>  samples/vfio-mdev/mdpy.c                      | 21 +++++------------
> --
>  samples/vfio-mdev/mtty.c                      | 18 ++++------------
>  10 files changed, 27 insertions(+), 72 deletions(-)
> 
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
> b/Documentation/driver-api/vfio-mediated-device.rst
> index b0c29e37f61b4..dcd1231a6fa84 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -217,7 +217,7 @@ Directories and files under the sysfs for Each
> Physical Device
>  
>  * name
>  
> -  This attribute should show human readable name. This is optional
> attribute.
> +  This attribute shows a human readable name.
>  
>  * description
>  
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
> b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 9b2d3b078a2c9..08fe7458b3610 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -138,20 +138,12 @@ static ssize_t description_show(struct
> mdev_type *mtype,
>                        type->conf->weight);
>  }
>  
> -static ssize_t name_show(struct mdev_type *mtype,
> -                        struct mdev_type_attribute *attr, char *buf)
> -{
> -       return sprintf(buf, "%s\n", mtype->sysfs_name);
> -}
> -
>  static MDEV_TYPE_ATTR_RO(available_instances);
>  static MDEV_TYPE_ATTR_RO(description);
> -static MDEV_TYPE_ATTR_RO(name);
>  
>  static const struct attribute *gvt_type_attrs[] = {
>         &mdev_type_attr_available_instances.attr,
>         &mdev_type_attr_description.attr,
> -       &mdev_type_attr_name.attr,
>         NULL,
>  };
>  
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c
> b/drivers/s390/cio/vfio_ccw_drv.c
> index 25a5de08b3902..e5f21c725326b 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -221,6 +221,7 @@ static int vfio_ccw_sch_probe(struct subchannel
> *sch)
>         dev_set_drvdata(&sch->dev, private);
>  
>         private->mdev_type.sysfs_name = "io";
> +       private->mdev_type.pretty_name = "I/O subchannel (Non-QDIO)";
>         private->mdev_types[0] = &private->mdev_type;
>         ret = mdev_register_parent(&private->parent, &sch->dev,
>                                    &vfio_ccw_mdev_driver,
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c
> b/drivers/s390/cio/vfio_ccw_ops.c
> index 4c7b181519228..394aab60dbd0a 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -44,13 +44,6 @@ static void vfio_ccw_dma_unmap(struct vfio_device
> *vdev, u64 iova, u64 length)
>         vfio_ccw_mdev_reset(private);
>  }
>  
> -static ssize_t name_show(struct mdev_type *mtype,
> -                        struct mdev_type_attribute *attr, char *buf)
> -{
> -       return sprintf(buf, "I/O subchannel (Non-QDIO)\n");
> -}
> -static MDEV_TYPE_ATTR_RO(name);
> -
>  static ssize_t available_instances_show(struct mdev_type *mtype,
>                                         struct mdev_type_attribute
> *attr,
>                                         char *buf)
> @@ -62,7 +55,6 @@ static ssize_t available_instances_show(struct
> mdev_type *mtype,
>  static MDEV_TYPE_ATTR_RO(available_instances);
>  
>  static const struct attribute *mdev_types_attrs[] = {
> -       &mdev_type_attr_name.attr,
>         &mdev_type_attr_available_instances.attr,
>         NULL,
>  };
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
> b/drivers/s390/crypto/vfio_ap_ops.c
> index d440acfbb261e..5d8dd7e837f3d 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -790,14 +790,6 @@ static void vfio_ap_mdev_remove(struct
> mdev_device *mdev)
>         vfio_put_device(&matrix_mdev->vdev);
>  }
>  
> -static ssize_t name_show(struct mdev_type *mtype,
> -                        struct mdev_type_attribute *attr, char *buf)
> -{
> -       return sprintf(buf, "%s\n", VFIO_AP_MDEV_NAME_HWVIRT);
> -}
> -
> -static MDEV_TYPE_ATTR_RO(name);
> -
>  static ssize_t available_instances_show(struct mdev_type *mtype,
>                                         struct mdev_type_attribute
> *attr,
>                                         char *buf)
> @@ -809,7 +801,6 @@ static ssize_t available_instances_show(struct
> mdev_type *mtype,
>  static MDEV_TYPE_ATTR_RO(available_instances);
>  
>  static const struct attribute *vfio_ap_mdev_type_attrs[] = {
> -       &mdev_type_attr_name.attr,
>         &mdev_type_attr_available_instances.attr,
>         NULL,
>  };
> @@ -1813,6 +1804,7 @@ int vfio_ap_mdev_register(void)
>                 return ret;
>  
>         matrix_dev->mdev_type.sysfs_name = VFIO_AP_MDEV_TYPE_HWVIRT;
> +       matrix_dev->mdev_type.pretty_name = VFIO_AP_MDEV_NAME_HWVIRT;
>         matrix_dev->mdev_types[0] = &matrix_dev->mdev_type;
>         ret = mdev_register_parent(&matrix_dev->parent, &matrix_dev-
> >device,
>                                    &vfio_ap_matrix_driver,
> diff --git a/drivers/vfio/mdev/mdev_sysfs.c
> b/drivers/vfio/mdev/mdev_sysfs.c
> index 60fc52ff92448..34583e6a97f27 100644
> --- a/drivers/vfio/mdev/mdev_sysfs.c
> +++ b/drivers/vfio/mdev/mdev_sysfs.c
> @@ -81,9 +81,19 @@ static ssize_t device_api_show(struct mdev_type
> *mtype,
>  }
>  static MDEV_TYPE_ATTR_RO(device_api);
>  
> +static ssize_t name_show(struct mdev_type *mtype,
> +                        struct mdev_type_attribute *attr, char *buf)
> +{
> +       return sprintf(buf, "%s\n",
> +               mtype->pretty_name ? mtype->pretty_name : mtype-
> >sysfs_name);
> +}
> +
> +static MDEV_TYPE_ATTR_RO(name);
> +
>  static struct attribute *mdev_types_core_attrs[] = {
>         &mdev_type_attr_create.attr,
>         &mdev_type_attr_device_api.attr,
> +       &mdev_type_attr_name.attr,
>         NULL,
>  };
>  
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index af1ff0165b8d3..4bb8a58b577b3 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -26,6 +26,7 @@ struct mdev_device {
>  struct mdev_type {
>         /* set by the driver before calling mdev_register parent: */
>         const char *sysfs_name;
> +       const char *pretty_name;
>  
>         /* set by the core, can be used drivers */
>         struct mdev_parent *parent;
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index a2fc13fade757..0b7585f16d8ab 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -101,26 +101,25 @@ MODULE_PARM_DESC(mem, "megabytes available to "
> MBOCHS_NAME " devices");
>  
>  static struct mbochs_type {
>         struct mdev_type type;
> -       const char *name;
>         u32 mbytes;
>         u32 max_x;
>         u32 max_y;
>  } mbochs_types[] = {
>         {
>                 .type.sysfs_name        = MBOCHS_TYPE_1,
> -               .name   = MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_1,
> +               .type.pretty_name       = MBOCHS_CLASS_NAME "-"
> MBOCHS_TYPE_1,
>                 .mbytes = 4,
>                 .max_x  = 800,
>                 .max_y  = 600,
>         }, {
>                 .type.sysfs_name        = MBOCHS_TYPE_2,
> -               .name   = MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_2,
> +               .type.pretty_name       = MBOCHS_CLASS_NAME "-"
> MBOCHS_TYPE_2,
>                 .mbytes = 16,
>                 .max_x  = 1920,
>                 .max_y  = 1440,
>         }, {
>                 .type.sysfs_name        = MBOCHS_TYPE_3,
> -               .name   = MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_3,
> +               .type.pretty_name       = MBOCHS_CLASS_NAME "-"
> MBOCHS_TYPE_3,
>                 .mbytes = 64,
>                 .max_x  = 0,
>                 .max_y  = 0,
> @@ -556,7 +555,7 @@ static int mbochs_init_dev(struct vfio_device
> *vdev)
>         mbochs_reset(mdev_state);
>  
>         dev_info(vdev->dev, "%s: %s, %d MB, %ld pages\n", __func__,
> -                type->name, type->mbytes, mdev_state->pagecount);
> +                type->type.pretty_name, type->mbytes, mdev_state-
> >pagecount);
>         return 0;
>  
>  err_vconfig:
> @@ -1351,16 +1350,6 @@ static const struct attribute_group
> *mdev_dev_groups[] = {
>         NULL,
>  };
>  
> -static ssize_t name_show(struct mdev_type *mtype,
> -                        struct mdev_type_attribute *attr, char *buf)
> -{
> -       struct mbochs_type *type =
> -               container_of(mtype, struct mbochs_type, type);
> -
> -       return sprintf(buf, "%s\n", type->name);
> -}
> -static MDEV_TYPE_ATTR_RO(name);
> -
>  static ssize_t description_show(struct mdev_type *mtype,
>                                 struct mdev_type_attribute *attr,
> char *buf)
>  {
> @@ -1385,7 +1374,6 @@ static ssize_t available_instances_show(struct
> mdev_type *mtype,
>  static MDEV_TYPE_ATTR_RO(available_instances);
>  
>  static const struct attribute *mdev_types_attrs[] = {
> -       &mdev_type_attr_name.attr,
>         &mdev_type_attr_description.attr,
>         &mdev_type_attr_available_instances.attr,
>         NULL,
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
> index f9069ed2750fa..90c6fed200b19 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -53,7 +53,6 @@ MODULE_PARM_DESC(count, "number of " MDPY_NAME "
> devices");
>  
>  static struct mdpy_type {
>         struct mdev_type type;
> -       const char *name;
>         u32 format;
>         u32 bytepp;
>         u32 width;
> @@ -61,21 +60,21 @@ static struct mdpy_type {
>  } mdpy_types[] = {
>         {
>                 .type.sysfs_name        = MDPY_TYPE_1,
> -               .name   = MDPY_CLASS_NAME "-" MDPY_TYPE_1,
> +               .type.pretty_name       = MDPY_CLASS_NAME "-"
> MDPY_TYPE_1,
>                 .format = DRM_FORMAT_XRGB8888,
>                 .bytepp = 4,
>                 .width  = 640,
>                 .height = 480,
>         }, {
>                 .type.sysfs_name        = MDPY_TYPE_2,
> -               .name   = MDPY_CLASS_NAME "-" MDPY_TYPE_2,
> +               .type.pretty_name       = MDPY_CLASS_NAME "-"
> MDPY_TYPE_2,
>                 .format = DRM_FORMAT_XRGB8888,
>                 .bytepp = 4,
>                 .width  = 1024,
>                 .height = 768,
>         }, {
>                 .type.sysfs_name        = MDPY_TYPE_3,
> -               .name   = MDPY_CLASS_NAME "-" MDPY_TYPE_3,
> +               .type.pretty_name       = MDPY_CLASS_NAME "-"
> MDPY_TYPE_3,
>                 .format = DRM_FORMAT_XRGB8888,
>                 .bytepp = 4,
>                 .width  = 1920,
> @@ -256,8 +255,8 @@ static int mdpy_init_dev(struct vfio_device
> *vdev)
>         mdpy_create_config_space(mdev_state);
>         mdpy_reset(mdev_state);
>  
> -       dev_info(vdev->dev, "%s: %s (%dx%d)\n", __func__, type->name,
> type->width,
> -                type->height);
> +       dev_info(vdev->dev, "%s: %s (%dx%d)\n", __func__, type-
> >type.pretty_name,
> +                type->width, type->height);
>  
>         mdpy_count++;
>         return 0;
> @@ -662,15 +661,6 @@ static const struct attribute_group
> *mdev_dev_groups[] = {
>         NULL,
>  };
>  
> -static ssize_t name_show(struct mdev_type *mtype,
> -                        struct mdev_type_attribute *attr, char *buf)
> -{
> -       struct mdpy_type *type = container_of(mtype, struct
> mdpy_type, type);
> -
> -       return sprintf(buf, "%s\n", type->name);
> -}
> -static MDEV_TYPE_ATTR_RO(name);
> -
>  static ssize_t description_show(struct mdev_type *mtype,
>                                 struct mdev_type_attribute *attr,
> char *buf)
>  {
> @@ -690,7 +680,6 @@ static ssize_t available_instances_show(struct
> mdev_type *mtype,
>  static MDEV_TYPE_ATTR_RO(available_instances);
>  
>  static const struct attribute *mdev_types_attrs[] = {
> -       &mdev_type_attr_name.attr,
>         &mdev_type_attr_description.attr,
>         &mdev_type_attr_available_instances.attr,
>         NULL,
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 064e71b28dd19..eab1b4442a96e 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -146,10 +146,11 @@ struct mdev_state {
>  static struct mtty_type {
>         struct mdev_type type;
>         int nr_ports;
> -       const char *name;
>  } mtty_types[2] = {
> -       { .nr_ports = 1, .type.sysfs_name = "1", .name = "Single port
> serial" },
> -       { .nr_ports = 2, .type.sysfs_name = "2", .name = "Dual port
> serial" },
> +       { .nr_ports = 1, .type.sysfs_name = "1",
> +         .type.pretty_name = "Single port serial" },
> +       { .nr_ports = 2, .type.sysfs_name = "2",
> +         .type.pretty_name = "Dual port serial" },
>  };
>  
>  static struct mdev_type *mtty_mdev_types[] = {
> @@ -1255,16 +1256,6 @@ static const struct attribute_group
> *mdev_dev_groups[] = {
>         NULL,
>  };
>  
> -static ssize_t name_show(struct mdev_type *mtype,
> -                        struct mdev_type_attribute *attr, char *buf)
> -{
> -       struct mtty_type *type = container_of(mtype, struct
> mtty_type, type);
> -
> -       return sysfs_emit(buf, "%s\n", type->name);
> -}
> -
> -static MDEV_TYPE_ATTR_RO(name);
> -
>  static ssize_t available_instances_show(struct mdev_type *mtype,
>                                         struct mdev_type_attribute
> *attr,
>                                         char *buf)
> @@ -1278,7 +1269,6 @@ static ssize_t available_instances_show(struct
> mdev_type *mtype,
>  static MDEV_TYPE_ATTR_RO(available_instances);
>  
>  static const struct attribute *mdev_types_attrs[] = {
> -       &mdev_type_attr_name.attr,
>         &mdev_type_attr_available_instances.attr,
>         NULL,
>  };