Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (120 commits)
  usb: don't update devnum for wusb devices
  wusb: make ep0_reinit available for modules
  wusb: devices dont use a set address
  wusb: teach choose_address() about wireless devices
  wusb: add link wusb-usb device
  wusb: add authenticathed bit to usb_dev
  USB: remove unnecessary type casting of urb->context
  usb serial: more fixes and groundwork for tty changes
  USB: replace remaining __FUNCTION__ occurrences
  USB: usbfs: export the URB_NO_INTERRUPT flag to userspace
  USB: fix compile problems in ehci-hcd
  USB: ehci: qh_completions cleanup and bugfix
  USB: cdc-acm: signedness fix
  USB: add documentation about callbacks
  USB: don't explicitly reenable root-hub status interrupts
  USB: OHCI: turn off RD when remote wakeup is disabled
  USB: HCDs use the do_remote_wakeup flag
  USB: g_file_storage: ignore bulk-out data after invalid CBW
  USB: serial: remove endpoints setting checks from core and header
  USB: serial: remove unneeded number endpoints settings
  ...

1 files changed, 50 insertions, 0 deletions

diff --git a/Documentation/usb/anchors.txt b/Documentation/usb/anchors.txt
new file mode 100644
index 000000000000..7304bcf5a306
--- /dev/null
+++ b/Documentation/usb/anchors.txt
@@ -0,0 +1,50 @@
+What is anchor?
+===============
+
+A USB driver needs to support some callbacks requiring
+a driver to cease all IO to an interface. To do so, a
+driver has to keep track of the URBs it has submitted
+to know they've all completed or to call usb_kill_urb
+for them. The anchor is a data structure takes care of
+keeping track of URBs and provides methods to deal with
+multiple URBs.
+
+Allocation and Initialisation
+=============================
+
+There's no API to allocate an anchor. It is simply declared
+as struct usb_anchor. init_usb_anchor() must be called to
+initialise the data structure.
+
+Deallocation
+============
+
+Once it has no more URBs associated with it, the anchor can be
+freed with normal memory management operations.
+
+Association and disassociation of URBs with anchors
+===================================================
+
+An association of URBs to an anchor is made by an explicit
+call to usb_anchor_urb(). The association is maintained until
+an URB is finished by (successfull) completion. Thus disassociation
+is automatic. A function is provided to forcibly finish (kill)
+all URBs associated with an anchor.
+Furthermore, disassociation can be made with usb_unanchor_urb()
+
+Operations on multitudes of URBs
+================================
+
+usb_kill_anchored_urbs()
+------------------------
+
+This function kills all URBs associated with an anchor. The URBs
+are called in the reverse temporal order they were submitted.
+This way no data can be reordered.
+
+usb_wait_anchor_empty_timeout()
+-------------------------------
+
+This function waits for all URBs associated with an anchor to finish
+or a timeout, whichever comes first. Its return value will tell you
+whether the timeout was reached.