diff options
| -rw-r--r-- | drivers/usb/core/devices.c | 6 | ||||
| -rw-r--r-- | drivers/usb/core/devio.c | 38 | ||||
| -rw-r--r-- | drivers/usb/core/hcd.c | 4 | ||||
| -rw-r--r-- | drivers/usb/core/hub.c | 93 | ||||
| -rw-r--r-- | drivers/usb/core/message.c | 16 | ||||
| -rw-r--r-- | drivers/usb/core/sysfs.c | 4 | ||||
| -rw-r--r-- | drivers/usb/core/usb.c | 138 | ||||
| -rw-r--r-- | drivers/usb/core/usb.h | 2 | ||||
| -rw-r--r-- | drivers/usb/host/ehci-hub.c | 2 | ||||
| -rw-r--r-- | drivers/usb/host/ohci-hub.c | 10 | ||||
| -rw-r--r-- | drivers/usb/host/ohci-pci.c | 8 | ||||
| -rw-r--r-- | include/linux/usb.h | 12 |
12 files changed, 242 insertions, 91 deletions
diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c index 195e365675af..50009ed51e8d 100644 --- a/drivers/usb/core/devices.c +++ b/drivers/usb/core/devices.c @@ -451,7 +451,7 @@ static char *usb_dump_string(char *start, char *end, const struct usb_device *de * nbytes - the maximum number of bytes to write * skip_bytes - the number of bytes to skip before writing anything * file_offset - the offset into the devices file on completion - * The caller must own the usbdev->serialize semaphore. + * The caller must own the device lock. */ static ssize_t usb_device_dump(char __user **buffer, size_t *nbytes, loff_t *skip_bytes, loff_t *file_offset, struct usb_device *usbdev, struct usb_bus *bus, int level, int index, int count) @@ -586,9 +586,9 @@ static ssize_t usb_device_read(struct file *file, char __user *buf, size_t nbyte /* recurse through all children of the root hub */ if (!bus->root_hub) continue; - down(&bus->root_hub->serialize); + usb_lock_device(bus->root_hub); ret = usb_device_dump(&buf, &nbytes, &skip_bytes, ppos, bus->root_hub, bus, 0, 0, 0); - up(&bus->root_hub->serialize); + usb_unlock_device(bus->root_hub); if (ret < 0) { up(&usb_bus_list_lock); return ret; diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 0b3bf6634ee4..c3e76e465c2b 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -113,7 +113,7 @@ static ssize_t usbdev_read(struct file *file, char __user *buf, size_t nbytes, l int i; pos = *ppos; - down(&dev->serialize); + usb_lock_device(dev); if (!connected(dev)) { ret = -ENODEV; goto err; @@ -175,7 +175,7 @@ static ssize_t usbdev_read(struct file *file, char __user *buf, size_t nbytes, l } err: - up(&dev->serialize); + usb_unlock_device(dev); return ret; } @@ -517,7 +517,7 @@ static int usbdev_release(struct inode *inode, struct file *file) struct usb_device *dev = ps->dev; unsigned int ifnum; - down(&dev->serialize); + usb_lock_device(dev); list_del_init(&ps->list); if (connected(dev)) { @@ -526,7 +526,7 @@ static int usbdev_release(struct inode *inode, struct file *file) releaseintf(ps, ifnum); destroy_all_async(ps); } - up(&dev->serialize); + usb_unlock_device(dev); usb_put_dev(dev); ps->dev = NULL; kfree(ps); @@ -558,10 +558,10 @@ static int proc_control(struct dev_state *ps, void __user *arg) snoop(&dev->dev, "control read: bRequest=%02x bRrequestType=%02x wValue=%04x wIndex=%04x\n", ctrl.bRequest, ctrl.bRequestType, ctrl.wValue, ctrl.wIndex); - up(&dev->serialize); + usb_unlock_device(dev); i = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), ctrl.bRequest, ctrl.bRequestType, ctrl.wValue, ctrl.wIndex, tbuf, ctrl.wLength, tmo); - down(&dev->serialize); + usb_lock_device(dev); if ((i > 0) && ctrl.wLength) { if (usbfs_snoop) { dev_info(&dev->dev, "control read: data "); @@ -589,10 +589,10 @@ static int proc_control(struct dev_state *ps, void __user *arg) printk ("%02x ", (unsigned char)(tbuf)[j]); printk("\n"); } - up(&dev->serialize); + usb_unlock_device(dev); i = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), ctrl.bRequest, ctrl.bRequestType, ctrl.wValue, ctrl.wIndex, tbuf, ctrl.wLength, tmo); - down(&dev->serialize); + usb_lock_device(dev); } free_page((unsigned long)tbuf); if (i<0) { @@ -636,9 +636,9 @@ static int proc_bulk(struct dev_state *ps, void __user *arg) kfree(tbuf); return -EINVAL; } - up(&dev->serialize); + usb_unlock_device(dev); i = usb_bulk_msg(dev, pipe, tbuf, len1, &len2, tmo); - down(&dev->serialize); + usb_lock_device(dev); if (!i && len2) { if (copy_to_user(bulk.data, tbuf, len2)) { kfree(tbuf); @@ -652,9 +652,9 @@ static int proc_bulk(struct dev_state *ps, void __user *arg) return -EFAULT; } } - up(&dev->serialize); + usb_unlock_device(dev); i = usb_bulk_msg(dev, pipe, tbuf, len1, &len2, tmo); - down(&dev->serialize); + usb_lock_device(dev); } kfree(tbuf); if (i < 0) { @@ -1025,9 +1025,9 @@ static int proc_reapurb(struct dev_state *ps, void __user *arg) break; if (signal_pending(current)) break; - up(&dev->serialize); + usb_unlock_device(dev); schedule(); - down(&dev->serialize); + usb_lock_device(dev); } remove_wait_queue(&ps->wait, &wait); set_current_state(TASK_RUNNING); @@ -1150,7 +1150,11 @@ static int proc_ioctl (struct dev_state *ps, void __user *arg) /* let kernel drivers try to (re)bind to the interface */ case USBDEVFS_CONNECT: + usb_unlock_device(ps->dev); + usb_lock_all_devices(); bus_rescan_devices(intf->dev.bus); + usb_unlock_all_devices(); + usb_lock_device(ps->dev); break; /* talk directly to the interface's driver */ @@ -1193,9 +1197,9 @@ static int usbdev_ioctl(struct inode *inode, struct file *file, unsigned int cmd if (!(file->f_mode & FMODE_WRITE)) return -EPERM; - down(&dev->serialize); + usb_lock_device(dev); if (!connected(dev)) { - up(&dev->serialize); + usb_unlock_device(dev); return -ENODEV; } @@ -1295,7 +1299,7 @@ static int usbdev_ioctl(struct inode *inode, struct file *file, unsigned int cmd ret = proc_ioctl(ps, p); break; } - up(&dev->serialize); + usb_unlock_device(dev); if (ret >= 0) inode->i_atime = CURRENT_TIME; return ret; diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index c1de465a10d1..ed3e723cc9c5 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -797,9 +797,9 @@ int usb_register_root_hub (struct usb_device *usb_dev, struct device *parent_dev return (retval < 0) ? retval : -EMSGSIZE; } - down (&usb_dev->serialize); + usb_lock_device (usb_dev); retval = usb_new_device (usb_dev); - up (&usb_dev->serialize); + usb_unlock_device (usb_dev); if (retval) { usb_dev->bus->root_hub = NULL; dev_err (parent_dev, "can't register root hub for %s, %d\n", diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 29bba5e78da3..36ef3db882a2 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -36,7 +36,9 @@ #include "hcd.h" #include "hub.h" -/* Protect struct usb_device state and children members */ +/* Protect struct usb_device->state and ->children members + * Note: Both are also protected by ->serialize, except that ->state can + * change to USB_STATE_NOTATTACHED even when the semaphore isn't held. */ static spinlock_t device_state_lock = SPIN_LOCK_UNLOCKED; /* khubd's worklist and its lock */ @@ -857,17 +859,6 @@ static void hub_start_disconnect(struct usb_device *hdev) } -static void recursively_mark_NOTATTACHED(struct usb_device *udev) -{ - int i; - - for (i = 0; i < udev->maxchild; ++i) { - if (udev->children[i]) - recursively_mark_NOTATTACHED(udev->children[i]); - } - udev->state = USB_STATE_NOTATTACHED; -} - /* grab device/port lock, returning index of that port (zero based). * protects the upstream link used by this device from concurrent * tree operations like suspend, resume, reset, and disconnect, which @@ -884,21 +875,16 @@ static int locktree(struct usb_device *udev) /* root hub is always the first lock in the series */ hdev = udev->parent; if (!hdev) { - down(&udev->serialize); + usb_lock_device(udev); return 0; } /* on the path from root to us, lock everything from * top down, dropping parent locks when not needed - * - * NOTE: if disconnect were to ignore the locking, we'd need - * to get extra refcounts to everything since hdev->children - * and udev->parent could be invalidated while we work... */ t = locktree(hdev); if (t < 0) return t; - spin_lock_irq(&device_state_lock); for (t = 0; t < hdev->maxchild; t++) { if (hdev->children[t] == udev) { /* everything is fail-fast once disconnect @@ -910,33 +896,45 @@ static int locktree(struct usb_device *udev) /* when everyone grabs locks top->bottom, * non-overlapping work may be concurrent */ - spin_unlock_irq(&device_state_lock); down(&udev->serialize); up(&hdev->serialize); return t; } } - spin_unlock_irq(&device_state_lock); - up(&hdev->serialize); + usb_unlock_device(hdev); return -ENODEV; } +static void recursively_mark_NOTATTACHED(struct usb_device *udev) +{ + int i; + + for (i = 0; i < udev->maxchild; ++i) { + if (udev->children[i]) + recursively_mark_NOTATTACHED(udev->children[i]); + } + udev->state = USB_STATE_NOTATTACHED; +} + /** * usb_set_device_state - change a device's current state (usbcore, hcds) * @udev: pointer to device whose state should be changed * @new_state: new state value to be stored * - * udev->state is _not_ protected by the device lock. This + * udev->state is _not_ fully protected by the device lock. Although + * most transitions are made only while holding the lock, the state can + * can change to USB_STATE_NOTATTACHED at almost any time. This * is so that devices can be marked as disconnected as soon as possible, - * without having to wait for the semaphore to be released. Instead, - * changes to the state must be protected by the device_state_lock spinlock. + * without having to wait for any semaphores to be released. As a result, + * all changes to any device's state must be protected by the + * device_state_lock spinlock. * * Once a device has been added to the device tree, all changes to its state * should be made using this routine. The state should _not_ be set directly. * * If udev->state is already USB_STATE_NOTATTACHED then no change is made. * Otherwise udev->state is set to new_state, and if new_state is - * USB_STATE_NOTATTACHED then all of udev's descendant's states are also set + * USB_STATE_NOTATTACHED then all of udev's descendants' states are also set * to USB_STATE_NOTATTACHED. */ void usb_set_device_state(struct usb_device *udev, @@ -987,11 +985,12 @@ static void release_address(struct usb_device *udev) /** * usb_disconnect - disconnect a device (usbcore-internal) - * @pdev: pointer to device being disconnected, into a locked hub + * @pdev: pointer to device being disconnected * Context: !in_interrupt () * - * Something got disconnected. Get rid of it, and all of its children. - * If *pdev is a normal device then the parent hub should be locked. + * Something got disconnected. Get rid of it and all of its children. + * + * If *pdev is a normal device then the parent hub must already be locked. * If *pdev is a root hub then this routine will acquire the * usb_bus_list_lock on behalf of the caller. * @@ -1017,9 +1016,11 @@ void usb_disconnect(struct usb_device **pdev) usb_set_device_state(udev, USB_STATE_NOTATTACHED); /* lock the bus list on behalf of HCDs unregistering their root hubs */ - if (!udev->parent) + if (!udev->parent) { down(&usb_bus_list_lock); - down(&udev->serialize); + usb_lock_device(udev); + } else + down(&udev->serialize); dev_info (&udev->dev, "USB disconnect, address %d\n", udev->devnum); @@ -1044,14 +1045,16 @@ void usb_disconnect(struct usb_device **pdev) usbfs_remove_device(udev); usb_remove_sysfs_dev_files(udev); - /* Avoid races with recursively_mark_NOTATTACHED() and locktree() */ + /* Avoid races with recursively_mark_NOTATTACHED() */ spin_lock_irq(&device_state_lock); *pdev = NULL; spin_unlock_irq(&device_state_lock); - up(&udev->serialize); - if (!udev->parent) + if (!udev->parent) { + usb_unlock_device(udev); up(&usb_bus_list_lock); + } else + up(&udev->serialize); device_unregister(&udev->dev); } @@ -1516,16 +1519,14 @@ static int __usb_suspend_device (struct usb_device *udev, int port, u32 state) { int status; + /* caller owns the udev device lock */ if (port < 0) return port; - /* NOTE: udev->serialize released on all real returns! */ - if (state <= udev->dev.power.power_state || state < PM_SUSPEND_MEM || udev->state == USB_STATE_SUSPENDED || udev->state == USB_STATE_NOTATTACHED) { - up(&udev->serialize); return 0; } @@ -1605,7 +1606,6 @@ static int __usb_suspend_device (struct usb_device *udev, int port, u32 state) if (status == 0) udev->dev.power.power_state = state; - up(&udev->serialize); return status; } @@ -1629,7 +1629,15 @@ static int __usb_suspend_device (struct usb_device *udev, int port, u32 state) */ int usb_suspend_device(struct usb_device *udev, u32 state) { - return __usb_suspend_device(udev, locktree(udev), state); + int port, status; + + port = locktree(udev); + if (port < 0) + return port; + + status = __usb_suspend_device(udev, port, state); + usb_unlock_device(udev); + return status; } /* @@ -1642,7 +1650,7 @@ static int finish_port_resume(struct usb_device *udev) int status; u16 devstatus; - /* caller owns udev->serialize */ + /* caller owns the udev device lock */ dev_dbg(&udev->dev, "usb resume\n"); udev->dev.power.power_state = PM_SUSPEND_ON; @@ -1822,10 +1830,12 @@ int usb_resume_device(struct usb_device *udev) status); } - up(&udev->serialize); + usb_unlock_device(udev); /* rebind drivers that had no suspend() */ + usb_lock_all_devices(); bus_rescan_devices(&usb_bus_type); + usb_unlock_all_devices(); return status; } @@ -1867,6 +1877,7 @@ static int hub_suspend(struct usb_interface *intf, u32 state) continue; down(&udev->serialize); status = __usb_suspend_device(udev, port, state); + up(&udev->serialize); if (status < 0) dev_dbg(&intf->dev, "suspend port %d --> %d\n", port, status); @@ -2595,7 +2606,7 @@ static void hub_events(void) } loop: - up(&hdev->serialize); + usb_unlock_device(hdev); usb_put_dev(hdev); } /* end while (1) */ diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 98695c68d687..e20dde5d793a 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -1132,6 +1132,8 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate) * use usb_set_interface() on the interfaces it claims. Resetting the whole * configuration would affect other drivers' interfaces. * + * The caller must own the device lock. + * * Returns zero on success, else a negative error code. */ int usb_reset_configuration(struct usb_device *dev) @@ -1142,9 +1144,9 @@ int usb_reset_configuration(struct usb_device *dev) if (dev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; - /* caller must own dev->serialize (config won't change) - * and the usb bus readlock (so driver bindings are stable); - * so calls during probe() are fine + /* caller must have locked the device and must own + * the usb bus readlock (so driver bindings are stable); + * calls during probe() are fine */ for (i = 1; i < 16; ++i) { @@ -1199,7 +1201,7 @@ static void release_interface(struct device *dev) * usb_set_configuration - Makes a particular device setting be current * @dev: the device whose configuration is being updated * @configuration: the configuration being chosen. - * Context: !in_interrupt(), caller holds dev->serialize + * Context: !in_interrupt(), caller owns the device lock * * This is used to enable non-default device modes. Not all devices * use this kind of configurability; many devices only have one @@ -1220,8 +1222,8 @@ static void release_interface(struct device *dev) * usb_set_interface(). * * This call is synchronous. The calling context must be able to sleep, - * and must not hold the driver model lock for USB; usb device driver - * probe() methods may not use this routine. + * must own the device lock, and must not hold the driver model's USB + * bus rwsem; usb device driver probe() methods cannot use this routine. * * Returns zero on success, or else the status code returned by the * underlying call that failed. On succesful completion, each interface @@ -1236,8 +1238,6 @@ int usb_set_configuration(struct usb_device *dev, int configuration) struct usb_interface **new_interfaces = NULL; int n, nintf; - /* dev->serialize guards all config changes */ - for (i = 0; i < dev->descriptor.bNumConfigurations; i++) { if (dev->config[i].desc.bConfigurationValue == configuration) { cp = &dev->config[i]; diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c index 78c5ca2f1051..007baee22013 100644 --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -55,9 +55,9 @@ set_bConfigurationValue (struct device *dev, const char *buf, size_t count) if (sscanf (buf, "%u", &config) != 1 || config > 255) return -EINVAL; - down(&udev->serialize); + usb_lock_device(udev); value = usb_set_configuration (udev, config); - up(&udev->serialize); + usb_unlock_device(udev); return (value < 0) ? value : count; } diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index de2edfb08582..93e2000043e4 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -39,6 +39,7 @@ #include <linux/spinlock.h> #include <linux/errno.h> #include <linux/smp_lock.h> +#include <linux/rwsem.h> #include <linux/usb.h> #include <asm/io.h> @@ -62,6 +63,8 @@ const char *usbcore_name = "usbcore"; int nousb; /* Disable USB when built into kernel image */ /* Not honored on modular build */ +static DECLARE_RWSEM(usb_all_devices_rwsem); + static int generic_probe (struct device *dev) { @@ -151,7 +154,9 @@ int usb_register(struct usb_driver *new_driver) new_driver->driver.probe = usb_probe_interface; new_driver->driver.remove = usb_unbind_interface; + usb_lock_all_devices(); retval = driver_register(&new_driver->driver); + usb_unlock_all_devices(); if (!retval) { pr_info("%s: registered new driver %s\n", @@ -180,7 +185,9 @@ void usb_deregister(struct usb_driver *driver) { pr_info("%s: deregistering driver %s\n", usbcore_name, driver->name); + usb_lock_all_devices(); driver_unregister (&driver->driver); + usb_unlock_all_devices(); usbfs_update_special(); } @@ -202,7 +209,7 @@ void usb_deregister(struct usb_driver *driver) * alternate settings available for this interfaces. * * Don't call this function unless you are bound to one of the interfaces - * on this device or you own the dev->serialize semaphore! + * on this device or you have locked the device! */ struct usb_interface *usb_ifnum_to_if(struct usb_device *dev, unsigned ifnum) { @@ -235,7 +242,7 @@ struct usb_interface *usb_ifnum_to_if(struct usb_device *dev, unsigned ifnum) * drivers avoid such mistakes. * * Don't call this function unless you are bound to the intf interface - * or you own the device's ->serialize semaphore! + * or you have locked the device! */ struct usb_host_interface *usb_altnum_to_altsetting(struct usb_interface *intf, unsigned int altnum) @@ -303,11 +310,12 @@ usb_epnum_to_ep_desc(struct usb_device *dev, unsigned epnum) * way to bind to an interface is to return the private data from * the driver's probe() method. * - * Callers must own the driver model's usb bus writelock. So driver - * probe() entries don't need extra locking, but other call contexts - * may need to explicitly claim that lock. + * Callers must own the device lock and the driver model's usb_bus_type.subsys + * writelock. So driver probe() entries don't need extra locking, + * but other call contexts may need to explicitly claim those locks. */ -int usb_driver_claim_interface(struct usb_driver *driver, struct usb_interface *iface, void* priv) +int usb_driver_claim_interface(struct usb_driver *driver, + struct usb_interface *iface, void* priv) { struct device *dev = &iface->dev; @@ -336,8 +344,8 @@ int usb_driver_claim_interface(struct usb_driver *driver, struct usb_interface * * also causes the driver disconnect() method to be called. * * This call is synchronous, and may not be used in an interrupt context. - * Callers must own the usb_device serialize semaphore and the driver model's - * usb bus writelock. So driver disconnect() entries don't need extra locking, + * Callers must own the device lock and the driver model's usb_bus_type.subsys + * writelock. So driver disconnect() entries don't need extra locking, * but other call contexts may need to explicitly claim those locks. */ void usb_driver_release_interface(struct usb_driver *driver, @@ -830,6 +838,112 @@ void usb_put_intf(struct usb_interface *intf) put_device(&intf->dev); } + +/* USB device locking + * + * Although locking USB devices should be straightforward, it is + * complicated by the way the driver-model core works. When a new USB + * driver is registered or unregistered, the core will automatically + * probe or disconnect all matching interfaces on all USB devices while + * holding the USB subsystem writelock. There's no good way for us to + * tell which devices will be used or to lock them beforehand; our only + * option is to effectively lock all the USB devices. + * + * We do that by using a private rw-semaphore, usb_all_devices_rwsem. + * When locking an individual device you must first acquire the rwsem's + * readlock. When a driver is registered or unregistered the writelock + * must be held. These actions are encapsulated in the subroutines + * below, so all a driver needs to do is call usb_lock_device() and + * usb_unlock_device(). + * + * Complications arise when several devices are to be locked at the same + * time. Only hub-aware drivers that are part of usbcore ever have to + * do this; nobody else needs to worry about it. The problem is that + * usb_lock_device() must not be called to lock a second device since it + * would acquire the rwsem's readlock reentrantly, leading to deadlock if + * another thread was waiting for the writelock. The solution is simple: + * + * When locking more than one device, call usb_lock_device() + * to lock the first one. Lock the others by calling + * down(&udev->serialize) directly. + * + * When unlocking multiple devices, use up(&udev->serialize) + * to unlock all but the last one. Unlock the last one by + * calling usb_unlock_device(). + * + * When locking both a device and its parent, always lock the + * the parent first. + */ + +/** + * usb_lock_device - acquire the lock for a usb device structure + * @udev: device that's being locked + * + * Use this routine when you don't hold any other device locks; + * to acquire nested inner locks call down(&udev->serialize) directly. + * This is necessary for proper interaction with usb_lock_all_devices(). + */ +void usb_lock_device(struct usb_device *udev) +{ + down_read(&usb_all_devices_rwsem); + down(&udev->serialize); +} + +/** + * usb_trylock_device - attempt to acquire the lock for a usb device structure + * @udev: device that's being locked + * + * Don't use this routine if you already hold a device lock; + * use down_trylock(&udev->serialize) instead. + * This is necessary for proper interaction with usb_lock_all_devices(). + * + * Returns 1 if successful, 0 if contention. + */ +int usb_trylock_device(struct usb_device *udev) +{ + if (!down_read_trylock(&usb_all_devices_rwsem)) + return 0; + if (down_trylock(&udev->serialize)) { + up_read(&usb_all_devices_rwsem); + return 0; + } + return 1; +} + +/** + * usb_unlock_device - release the lock for a usb device structure + * @udev: device that's being unlocked + * + * Use this routine when releasing the only device lock you hold; + * to release inner nested locks call up(&udev->serialize) directly. + * This is necessary for proper interaction with usb_lock_all_devices(). + */ +void usb_unlock_device(struct usb_device *udev) +{ + up(&udev->serialize); + up_read(&usb_all_devices_rwsem); +} + +/** + * usb_lock_all_devices - acquire the lock for all usb device structures + * + * This is necessary when registering a new driver or probing a bus, + * since the driver-model core may try to use any usb_device. + */ +void usb_lock_all_devices(void) +{ + down_write(&usb_all_devices_rwsem); +} + +/** + * usb_unlock_all_devices - release the lock for all usb device structures + */ +void usb_unlock_all_devices(void) +{ + up_write(&usb_all_devices_rwsem); +} + + static struct usb_device *match_device(struct usb_device *dev, u16 vendor_id, u16 product_id) { @@ -851,8 +965,10 @@ static struct usb_device *match_device(struct usb_device *dev, /* look through all of the children of this device */ for (child = 0; child < dev->maxchild; ++child) { if (dev->children[child]) { + down(&dev->children[child]->serialize); ret_dev = match_device(dev->children[child], vendor_id, product_id); + up(&dev->children[child]->serialize); if (ret_dev) goto exit; } @@ -887,7 +1003,9 @@ struct usb_device *usb_find_device(u16 vendor_id, u16 product_id) bus = container_of(buslist, struct usb_bus, bus_list); if (!bus->root_hub) continue; + usb_lock_device(bus->root_hub); dev = match_device(bus->root_hub, vendor_id, product_id); + usb_unlock_device(bus->root_hub); if (dev) goto exit; } @@ -1373,6 +1491,10 @@ EXPORT_SYMBOL(usb_put_dev); EXPORT_SYMBOL(usb_get_dev); EXPORT_SYMBOL(usb_hub_tt_clear_buffer); +EXPORT_SYMBOL(usb_lock_device); +EXPORT_SYMBOL(usb_trylock_device); +EXPORT_SYMBOL(usb_unlock_device); + EXPORT_SYMBOL(usb_driver_claim_interface); EXPORT_SYMBOL(usb_driver_release_interface); EXPORT_SYMBOL(usb_match_id); diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h index 8e9c923bff0b..30d2cf7dd762 100644 --- a/drivers/usb/core/usb.h +++ b/drivers/usb/core/usb.h @@ -22,6 +22,8 @@ extern int usb_get_device_descriptor(struct usb_device *dev, unsigned int size); extern int usb_set_configuration(struct usb_device *dev, int configuration); +extern void usb_lock_all_devices(void); +extern void usb_unlock_all_devices(void); /* for labeling diagnostics */ extern const char *usbcore_name; diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c index 438701e17946..4a23fbf1f7af 100644 --- a/drivers/usb/host/ehci-hub.c +++ b/drivers/usb/host/ehci-hub.c @@ -81,7 +81,7 @@ static int ehci_hub_suspend (struct usb_hcd *hcd) } -/* caller owns root->serialize, and should reset/reinit on error */ +/* caller has locked the root hub, and should reset/reinit on error */ static int ehci_hub_resume (struct usb_hcd *hcd) { struct ehci_hcd *ehci = hcd_to_ehci (hcd); diff --git a/drivers/usb/host/ohci-hub.c b/drivers/usb/host/ohci-hub.c index 1f21cf815ad4..d7a28d8eefb9 100644 --- a/drivers/usb/host/ohci-hub.c +++ b/drivers/usb/host/ohci-hub.c @@ -138,7 +138,7 @@ static inline struct ed *find_head (struct ed *ed) return ed; } -/* caller owns root->serialize */ +/* caller has locked the root hub */ static int ohci_hub_resume (struct usb_hcd *hcd) { struct ohci_hcd *ohci = hcd_to_ohci (hcd); @@ -282,9 +282,9 @@ static void ohci_rh_resume (void *_hcd) { struct usb_hcd *hcd = _hcd; - down (&hcd->self.root_hub->serialize); + usb_lock_device (hcd->self.root_hub); (void) ohci_hub_resume (hcd); - up (&hcd->self.root_hub->serialize); + usb_unlock_device (hcd->self.root_hub); } #else @@ -362,12 +362,12 @@ ohci_hub_status_data (struct usb_hcd *hcd, char *buf) && ((OHCI_CTRL_HCFS | OHCI_SCHED_ENABLES) & ohci->hc_control) == OHCI_USB_OPER - && down_trylock (&hcd->self.root_hub->serialize) == 0 + && usb_trylock_device (hcd->self.root_hub) ) { ohci_vdbg (ohci, "autosuspend\n"); (void) ohci_hub_suspend (&ohci->hcd); ohci->hcd.state = USB_STATE_RUNNING; - up (&hcd->self.root_hub->serialize); + usb_unlock_device (hcd->self.root_hub); } #endif diff --git a/drivers/usb/host/ohci-pci.c b/drivers/usb/host/ohci-pci.c index b1dbea9e4b23..23f6b5f3fee5 100644 --- a/drivers/usb/host/ohci-pci.c +++ b/drivers/usb/host/ohci-pci.c @@ -121,9 +121,9 @@ static int ohci_pci_suspend (struct usb_hcd *hcd, u32 state) #ifdef CONFIG_USB_SUSPEND (void) usb_suspend_device (hcd->self.root_hub, state); #else - down (&hcd->self.root_hub->serialize); + usb_lock_device (hcd->self.root_hub); (void) ohci_hub_suspend (hcd); - up (&hcd->self.root_hub->serialize); + usb_unlock_device (hcd->self.root_hub); #endif /* let things settle down a bit */ @@ -169,9 +169,9 @@ static int ohci_pci_resume (struct usb_hcd *hcd) /* get extra cleanup even if remote wakeup isn't in use */ retval = usb_resume_device (hcd->self.root_hub); #else - down (&hcd->self.root_hub->serialize); + usb_lock_device (hcd->self.root_hub); retval = ohci_hub_resume (hcd); - up (&hcd->self.root_hub->serialize); + usb_unlock_device (hcd->self.root_hub); #endif if (retval == 0) { diff --git a/include/linux/usb.h b/include/linux/usb.h index d07d5aba9e7f..67a8d7bce43b 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -281,6 +281,14 @@ struct usb_bus { struct usb_tt; +/* + * struct usb_device - kernel's representation of a USB device + * + * FIXME: Write the kerneldoc! + * + * Usbcore drivers should not set usbdev->state directly. Instead use + * usb_set_device_state(). + */ struct usb_device { int devnum; /* Address on USB bus */ char devpath [16]; /* Use in messages: /port/port/... */ @@ -331,6 +339,10 @@ struct usb_device { extern struct usb_device *usb_get_dev(struct usb_device *dev); extern void usb_put_dev(struct usb_device *dev); +extern void usb_lock_device(struct usb_device *udev); +extern int usb_trylock_device(struct usb_device *udev); +extern void usb_unlock_device(struct usb_device *udev); + /* mostly for devices emulating SCSI over USB */ extern int usb_reset_device(struct usb_device *dev); extern int __usb_reset_device(struct usb_device *dev); |