diff options
| -rw-r--r-- | Documentation/usb/URB.txt | 22 | ||||
| -rw-r--r-- | Documentation/usb/usbmon.txt | 6 | ||||
| -rw-r--r-- | drivers/usb/Kconfig | 16 | ||||
| -rw-r--r-- | drivers/usb/core/message.c | 11 | ||||
| -rw-r--r-- | drivers/usb/core/urb.c | 12 | ||||
| -rw-r--r-- | drivers/usb/gadget/inode.c | 1 | ||||
| -rw-r--r-- | drivers/usb/storage/usb.c | 30 |
7 files changed, 81 insertions, 17 deletions
diff --git a/Documentation/usb/URB.txt b/Documentation/usb/URB.txt index 8ffce746d49..00d2c644068 100644 --- a/Documentation/usb/URB.txt +++ b/Documentation/usb/URB.txt @@ -168,6 +168,28 @@ that if the completion handler or anyone else tries to resubmit it they will get a -EPERM error. Thus you can be sure that when usb_kill_urb() returns, the URB is totally idle. +There is a lifetime issue to consider. An URB may complete at any +time, and the completion handler may free the URB. If this happens +while usb_unlink_urb or usb_kill_urb is running, it will cause a +memory-access violation. The driver is responsible for avoiding this, +which often means some sort of lock will be needed to prevent the URB +from being deallocated while it is still in use. + +On the other hand, since usb_unlink_urb may end up calling the +completion handler, the handler must not take any lock that is held +when usb_unlink_urb is invoked. The general solution to this problem +is to increment the URB's reference count while holding the lock, then +drop the lock and call usb_unlink_urb or usb_kill_urb, and then +decrement the URB's reference count. You increment the reference +count by calling + + struct urb *usb_get_urb(struct urb *urb) + +(ignore the return value; it is the same as the argument) and +decrement the reference count by calling usb_free_urb. Of course, +none of this is necessary if there's no danger of the URB being freed +by the completion handler. + 1.7. What about the completion handler? diff --git a/Documentation/usb/usbmon.txt b/Documentation/usb/usbmon.txt index 5335fa8b06e..c42bb9cd3b4 100644 --- a/Documentation/usb/usbmon.txt +++ b/Documentation/usb/usbmon.txt @@ -183,10 +183,10 @@ An input control transfer to get a port status. d5ea89a0 3575914555 S Ci:1:001:0 s a3 00 0000 0003 0004 4 < d5ea89a0 3575914560 C Ci:1:001:0 0 4 = 01050000 -An output bulk transfer to send a SCSI command 0x5E in a 31-byte Bulk wrapper -to a storage device at address 5: +An output bulk transfer to send a SCSI command 0x28 (READ_10) in a 31-byte +Bulk wrapper to a storage device at address 5: -dd65f0e8 4128379752 S Bo:1:005:2 -115 31 = 55534243 5e000000 00000000 00000600 00000000 00000000 00000000 000000 +dd65f0e8 4128379752 S Bo:1:005:2 -115 31 = 55534243 ad000000 00800000 80010a28 20000000 20000040 00000000 000000 dd65f0e8 4128379808 C Bo:1:005:2 0 31 > * Raw binary format and API diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig index cbd8f5f8059..76316a33061 100644 --- a/drivers/usb/Kconfig +++ b/drivers/usb/Kconfig @@ -2,14 +2,6 @@ # USB device configuration # -menuconfig USB_SUPPORT - bool "USB support" - depends on HAS_IOMEM - default y - ---help--- - This option adds core support for Universal Serial Bus (USB). - You will also need drivers from the following menu to make use of it. - # many non-PCI SOC chips embed OHCI config USB_ARCH_HAS_OHCI boolean @@ -63,6 +55,14 @@ config USB_ARCH_HAS_XHCI boolean default PCI +menuconfig USB_SUPPORT + bool "USB support" + depends on HAS_IOMEM + default y + ---help--- + This option adds core support for Universal Serial Bus (USB). + You will also need drivers from the following menu to make use of it. + if USB_SUPPORT config USB_COMMON diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index b3bdfede45e..aed3e07942d 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -308,7 +308,8 @@ static void sg_complete(struct urb *urb) retval = usb_unlink_urb(io->urbs [i]); if (retval != -EINPROGRESS && retval != -ENODEV && - retval != -EBUSY) + retval != -EBUSY && + retval != -EIDRM) dev_err(&io->dev->dev, "%s, unlink --> %d\n", __func__, retval); @@ -317,7 +318,6 @@ static void sg_complete(struct urb *urb) } spin_lock(&io->lock); } - urb->dev = NULL; /* on the last completion, signal usb_sg_wait() */ io->bytes += urb->actual_length; @@ -524,7 +524,6 @@ void usb_sg_wait(struct usb_sg_request *io) case -ENXIO: /* hc didn't queue this one */ case -EAGAIN: case -ENOMEM: - io->urbs[i]->dev = NULL; retval = 0; yield(); break; @@ -542,7 +541,6 @@ void usb_sg_wait(struct usb_sg_request *io) /* fail any uncompleted urbs */ default: - io->urbs[i]->dev = NULL; io->urbs[i]->status = retval; dev_dbg(&io->dev->dev, "%s, submit --> %d\n", __func__, retval); @@ -593,7 +591,10 @@ void usb_sg_cancel(struct usb_sg_request *io) if (!io->urbs [i]->dev) continue; retval = usb_unlink_urb(io->urbs [i]); - if (retval != -EINPROGRESS && retval != -EBUSY) + if (retval != -EINPROGRESS + && retval != -ENODEV + && retval != -EBUSY + && retval != -EIDRM) dev_warn(&io->dev->dev, "%s, unlink --> %d\n", __func__, retval); } diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index 7239a73c1b8..cd9b3a2cd8a 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -539,6 +539,10 @@ EXPORT_SYMBOL_GPL(usb_submit_urb); * never submitted, or it was unlinked before, or the hardware is already * finished with it), even if the completion handler has not yet run. * + * The URB must not be deallocated while this routine is running. In + * particular, when a driver calls this routine, it must insure that the + * completion handler cannot deallocate the URB. + * * Unlinking and Endpoint Queues: * * [The behaviors and guarantees described below do not apply to virtual @@ -603,6 +607,10 @@ EXPORT_SYMBOL_GPL(usb_unlink_urb); * with error -EPERM. Thus even if the URB's completion handler always * tries to resubmit, it will not succeed and the URB will become idle. * + * The URB must not be deallocated while this routine is running. In + * particular, when a driver calls this routine, it must insure that the + * completion handler cannot deallocate the URB. + * * This routine may not be used in an interrupt context (such as a bottom * half or a completion handler), or when holding a spinlock, or in other * situations where the caller can't schedule(). @@ -640,6 +648,10 @@ EXPORT_SYMBOL_GPL(usb_kill_urb); * with error -EPERM. Thus even if the URB's completion handler always * tries to resubmit, it will not succeed and the URB will become idle. * + * The URB must not be deallocated while this routine is running. In + * particular, when a driver calls this routine, it must insure that the + * completion handler cannot deallocate the URB. + * * This routine may not be used in an interrupt context (such as a bottom * half or a completion handler), or when holding a spinlock, or in other * situations where the caller can't schedule(). diff --git a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c index 8793f32bab1..e58b1644297 100644 --- a/drivers/usb/gadget/inode.c +++ b/drivers/usb/gadget/inode.c @@ -1574,7 +1574,6 @@ static void destroy_ep_files (struct dev_data *dev) DBG (dev, "%s %d\n", __func__, dev->state); /* dev->state must prevent interference */ -restart: spin_lock_irq (&dev->lock); while (!list_empty(&dev->epfiles)) { struct ep_data *ep; diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c index c18538e4a6d..2653e73db62 100644 --- a/drivers/usb/storage/usb.c +++ b/drivers/usb/storage/usb.c @@ -132,6 +132,35 @@ static struct us_unusual_dev for_dynamic_ids = #undef COMPLIANT_DEV #undef USUAL_DEV +#ifdef CONFIG_LOCKDEP + +static struct lock_class_key us_interface_key[USB_MAXINTERFACES]; + +static void us_set_lock_class(struct mutex *mutex, + struct usb_interface *intf) +{ + struct usb_device *udev = interface_to_usbdev(intf); + struct usb_host_config *config = udev->actconfig; + int i; + + for (i = 0; i < config->desc.bNumInterfaces; i++) { + if (config->interface[i] == intf) + break; + } + + BUG_ON(i == config->desc.bNumInterfaces); + + lockdep_set_class(mutex, &us_interface_key[i]); +} + +#else + +static void us_set_lock_class(struct mutex *mutex, + struct usb_interface *intf) +{ +} + +#endif #ifdef CONFIG_PM /* Minimal support for suspend and resume */ @@ -895,6 +924,7 @@ int usb_stor_probe1(struct us_data **pus, *pus = us = host_to_us(host); memset(us, 0, sizeof(struct us_data)); mutex_init(&(us->dev_mutex)); + us_set_lock_class(&us->dev_mutex, intf); init_completion(&us->cmnd_ready); init_completion(&(us->notify)); init_waitqueue_head(&us->delay_wait); |