vfio/mdev: consolidate all the name sysfs into the core code

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>
Link: https://lore.kernel.org/r/20220923092652.100656-12-hch@lst.deSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

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
 

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,
 };
 

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,

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,
 };

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,

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,
 };
 

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;

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,

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,

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,
 };