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USB: create attributes before sending uevent
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This patch (as1087d) fixes a long-standing problem in usbcore: Device,
interface, and endpoint attributes aren't added until _after_ the
creation uevent has already been broadcast.

Unfortunately there are a few attributes which cannot be created that
early.  The "descriptors" attribute is binary and so must be created
separately.  The power-management attributes can't be created until
the dev/power/ group exists.  And the interface string can vary from
one altsetting to another, so it has to be created dynamically.

Signed-off-by: Alan Stern <[email protected]>
Cc: Kay Sievers <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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@AlanStern @gregkh
AlanStern authored and gregkh committed May 14, 2008
1 parent 6986a97 commit 2e5f10e
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Showing 5 changed files with 96 additions and 58 deletions.
11 changes: 5 additions & 6 deletions drivers/usb/core/endpoint.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -156,6 +156,10 @@ static struct attribute *ep_dev_attrs[] = {
static struct attribute_group ep_dev_attr_grp = {
.attrs = ep_dev_attrs,
};
static struct attribute_group *ep_dev_groups[] = {
&ep_dev_attr_grp,
NULL
};

static int usb_endpoint_major_init(void)
{
Expand Down Expand Up @@ -298,6 +302,7 @@ int usb_create_ep_files(struct device *parent,

ep_dev->desc = &endpoint->desc;
ep_dev->udev = udev;
ep_dev->dev.groups = ep_dev_groups;
ep_dev->dev.devt = MKDEV(usb_endpoint_major, ep_dev->minor);
ep_dev->dev.class = ep_class->class;
ep_dev->dev.parent = parent;
Expand All @@ -309,9 +314,6 @@ int usb_create_ep_files(struct device *parent,
retval = device_register(&ep_dev->dev);
if (retval)
goto error_chrdev;
retval = sysfs_create_group(&ep_dev->dev.kobj, &ep_dev_attr_grp);
if (retval)
goto error_group;

/* create the symlink to the old-style "ep_XX" directory */
sprintf(name, "ep_%02x", endpoint->desc.bEndpointAddress);
Expand All @@ -322,8 +324,6 @@ int usb_create_ep_files(struct device *parent,
return retval;

error_link:
sysfs_remove_group(&ep_dev->dev.kobj, &ep_dev_attr_grp);
error_group:
device_unregister(&ep_dev->dev);
destroy_endpoint_class();
return retval;
Expand All @@ -348,7 +348,6 @@ void usb_remove_ep_files(struct usb_host_endpoint *endpoint)

sprintf(name, "ep_%02x", endpoint->desc.bEndpointAddress);
sysfs_remove_link(&ep_dev->dev.parent->kobj, name);
sysfs_remove_group(&ep_dev->dev.kobj, &ep_dev_attr_grp);
device_unregister(&ep_dev->dev);
endpoint->ep_dev = NULL;
destroy_endpoint_class();
Expand Down
1 change: 1 addition & 0 deletions drivers/usb/core/message.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1607,6 +1607,7 @@ int usb_set_configuration(struct usb_device *dev, int configuration)
intf->dev.driver = NULL;
intf->dev.bus = &usb_bus_type;
intf->dev.type = &usb_if_device_type;
intf->dev.groups = usb_interface_groups;
intf->dev.dma_mask = dev->dev.dma_mask;
device_initialize(&intf->dev);
mark_quiesced(intf);
Expand Down
137 changes: 85 additions & 52 deletions drivers/usb/core/sysfs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -538,6 +538,46 @@ static struct attribute_group dev_attr_grp = {
.attrs = dev_attrs,
};

/* When modifying this list, be sure to modify dev_string_attrs_are_visible()
* accordingly.
*/
static struct attribute *dev_string_attrs[] = {
&dev_attr_manufacturer.attr,
&dev_attr_product.attr,
&dev_attr_serial.attr,
NULL
};

static mode_t dev_string_attrs_are_visible(struct kobject *kobj,
struct attribute *a, int n)
{
struct usb_device *udev = to_usb_device(
container_of(kobj, struct device, kobj));

if (a == &dev_attr_manufacturer.attr) {
if (udev->manufacturer == NULL)
return 0;
} else if (a == &dev_attr_product.attr) {
if (udev->product == NULL)
return 0;
} else if (a == &dev_attr_serial.attr) {
if (udev->serial == NULL)
return 0;
}
return a->mode;
}

static struct attribute_group dev_string_attr_grp = {
.attrs = dev_string_attrs,
.is_visible = dev_string_attrs_are_visible,
};

struct attribute_group *usb_device_groups[] = {
&dev_attr_grp,
&dev_string_attr_grp,
NULL
};

/* Binary descriptors */

static ssize_t
Expand Down Expand Up @@ -591,10 +631,9 @@ int usb_create_sysfs_dev_files(struct usb_device *udev)
struct device *dev = &udev->dev;
int retval;

retval = sysfs_create_group(&dev->kobj, &dev_attr_grp);
if (retval)
return retval;

/* Unforunately these attributes cannot be created before
* the uevent is broadcast.
*/
retval = device_create_bin_file(dev, &dev_bin_attr_descriptors);
if (retval)
goto error;
Expand All @@ -607,21 +646,6 @@ int usb_create_sysfs_dev_files(struct usb_device *udev)
if (retval)
goto error;

if (udev->manufacturer) {
retval = device_create_file(dev, &dev_attr_manufacturer);
if (retval)
goto error;
}
if (udev->product) {
retval = device_create_file(dev, &dev_attr_product);
if (retval)
goto error;
}
if (udev->serial) {
retval = device_create_file(dev, &dev_attr_serial);
if (retval)
goto error;
}
retval = usb_create_ep_files(dev, &udev->ep0, udev);
if (retval)
goto error;
Expand All @@ -636,13 +660,9 @@ void usb_remove_sysfs_dev_files(struct usb_device *udev)
struct device *dev = &udev->dev;

usb_remove_ep_files(&udev->ep0);
device_remove_file(dev, &dev_attr_manufacturer);
device_remove_file(dev, &dev_attr_product);
device_remove_file(dev, &dev_attr_serial);
remove_power_attributes(dev);
remove_persist_attributes(dev);
device_remove_bin_file(dev, &dev_bin_attr_descriptors);
sysfs_remove_group(&dev->kobj, &dev_attr_grp);
}

/* Interface Accociation Descriptor fields */
Expand Down Expand Up @@ -688,17 +708,15 @@ static ssize_t show_interface_string(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct usb_interface *intf;
struct usb_device *udev;
int len;
char *string;

intf = to_usb_interface(dev);
udev = interface_to_usbdev(intf);
len = snprintf(buf, 256, "%s", intf->cur_altsetting->string);
if (len < 0)
string = intf->cur_altsetting->string;
barrier(); /* The altsetting might change! */

if (!string)
return 0;
buf[len] = '\n';
buf[len+1] = 0;
return len+1;
return sprintf(buf, "%s\n", string);
}
static DEVICE_ATTR(interface, S_IRUGO, show_interface_string, NULL);

Expand Down Expand Up @@ -727,18 +745,6 @@ static ssize_t show_modalias(struct device *dev,
}
static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);

static struct attribute *intf_assoc_attrs[] = {
&dev_attr_iad_bFirstInterface.attr,
&dev_attr_iad_bInterfaceCount.attr,
&dev_attr_iad_bFunctionClass.attr,
&dev_attr_iad_bFunctionSubClass.attr,
&dev_attr_iad_bFunctionProtocol.attr,
NULL,
};
static struct attribute_group intf_assoc_attr_grp = {
.attrs = intf_assoc_attrs,
};

static struct attribute *intf_attrs[] = {
&dev_attr_bInterfaceNumber.attr,
&dev_attr_bAlternateSetting.attr,
Expand All @@ -753,6 +759,37 @@ static struct attribute_group intf_attr_grp = {
.attrs = intf_attrs,
};

static struct attribute *intf_assoc_attrs[] = {
&dev_attr_iad_bFirstInterface.attr,
&dev_attr_iad_bInterfaceCount.attr,
&dev_attr_iad_bFunctionClass.attr,
&dev_attr_iad_bFunctionSubClass.attr,
&dev_attr_iad_bFunctionProtocol.attr,
NULL,
};

static mode_t intf_assoc_attrs_are_visible(struct kobject *kobj,
struct attribute *a, int n)
{
struct usb_interface *intf = to_usb_interface(
container_of(kobj, struct device, kobj));

if (intf->intf_assoc == NULL)
return 0;
return a->mode;
}

static struct attribute_group intf_assoc_attr_grp = {
.attrs = intf_assoc_attrs,
.is_visible = intf_assoc_attrs_are_visible,
};

struct attribute_group *usb_interface_groups[] = {
&intf_attr_grp,
&intf_assoc_attr_grp,
NULL
};

static inline void usb_create_intf_ep_files(struct usb_interface *intf,
struct usb_device *udev)
{
Expand All @@ -777,23 +814,21 @@ static inline void usb_remove_intf_ep_files(struct usb_interface *intf)

int usb_create_sysfs_intf_files(struct usb_interface *intf)
{
struct device *dev = &intf->dev;
struct usb_device *udev = interface_to_usbdev(intf);
struct usb_host_interface *alt = intf->cur_altsetting;
int retval;

if (intf->sysfs_files_created)
return 0;
retval = sysfs_create_group(&dev->kobj, &intf_attr_grp);
if (retval)
return retval;

/* The interface string may be present in some altsettings
* and missing in others. Hence its attribute cannot be created
* before the uevent is broadcast.
*/
if (alt->string == NULL)
alt->string = usb_cache_string(udev, alt->desc.iInterface);
if (alt->string)
retval = device_create_file(dev, &dev_attr_interface);
if (intf->intf_assoc)
retval = sysfs_create_group(&dev->kobj, &intf_assoc_attr_grp);
retval = device_create_file(&intf->dev, &dev_attr_interface);
usb_create_intf_ep_files(intf, udev);
intf->sysfs_files_created = 1;
return 0;
Expand All @@ -807,7 +842,5 @@ void usb_remove_sysfs_intf_files(struct usb_interface *intf)
return;
usb_remove_intf_ep_files(intf);
device_remove_file(dev, &dev_attr_interface);
sysfs_remove_group(&dev->kobj, &intf_attr_grp);
sysfs_remove_group(&intf->dev.kobj, &intf_assoc_attr_grp);
intf->sysfs_files_created = 0;
}
1 change: 1 addition & 0 deletions drivers/usb/core/usb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -291,6 +291,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
device_initialize(&dev->dev);
dev->dev.bus = &usb_bus_type;
dev->dev.type = &usb_device_type;
dev->dev.groups = usb_device_groups;
dev->dev.dma_mask = bus->controller->dma_mask;
set_dev_node(&dev->dev, dev_to_node(bus->controller));
dev->state = USB_STATE_ATTACHED;
Expand Down
4 changes: 4 additions & 0 deletions drivers/usb/core/usb.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,10 @@ static inline int is_active(const struct usb_interface *f)
/* for labeling diagnostics */
extern const char *usbcore_name;

/* sysfs stuff */
extern struct attribute_group *usb_device_groups[];
extern struct attribute_group *usb_interface_groups[];

/* usbfs stuff */
extern struct mutex usbfs_mutex;
extern struct usb_driver usbfs_driver;
Expand Down

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