This patch modifies the usb_hcd_giveback_urb() routine in usbcore to
insure that interrupts will be disabled when an URB's completion
handler is called, even if they were enabled initially.
It also modifies ehci-hcd to enable interrupts when giving back URBs,
if possible. Unfortunately it isn't always possible, because there
are pathways that can give back URBs in hardirq context (during the
I/O watchdog hrtimer routine, for example).
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/core/hcd.c | 4 ++++
drivers/usb/host/ehci-q.c | 12 ++++++++++--
2 files changed, 14 insertions(+), 2 deletions(-)
Index: usb-3.11/drivers/usb/core/hcd.c
===================================================================
--- usb-3.11.orig/drivers/usb/core/hcd.c
+++ usb-3.11/drivers/usb/core/hcd.c
@@ -1667,6 +1667,8 @@ int usb_hcd_unlink_urb (struct urb *urb,
*/
void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
{
+ unsigned long flags;
+
urb->hcpriv = NULL;
if (unlikely(urb->unlinked))
status = urb->unlinked;
@@ -1681,7 +1683,9 @@ void usb_hcd_giveback_urb(struct usb_hcd
/* pass ownership to the completion handler */
urb->status = status;
+ local_irq_save(flags);
urb->complete (urb);
+ local_irq_restore(flags);
atomic_dec (&urb->use_count);
if (unlikely(atomic_read(&urb->reject)))
wake_up (&usb_kill_urb_queue);
Index: usb-3.11/drivers/usb/host/ehci-q.c
===================================================================
--- usb-3.11.orig/drivers/usb/host/ehci-q.c
+++ usb-3.11/drivers/usb/host/ehci-q.c
@@ -257,6 +257,8 @@ ehci_urb_done(struct ehci_hcd *ehci, str
__releases(ehci->lock)
__acquires(ehci->lock)
{
+ bool enable_ints = !in_irq();
+
if (usb_pipetype(urb->pipe) == PIPE_INTERRUPT) {
/* ... update hc-wide periodic stats */
ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
@@ -283,9 +285,15 @@ __acquires(ehci->lock)
/* complete() can reenter this HCD */
usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
- spin_unlock (&ehci->lock);
+
+ /* This routine can be called from hardirq or softirq context */
+ spin_unlock(&ehci->lock);
+ if (enable_ints)
+ local_irq_enable();
usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status);
- spin_lock (&ehci->lock);
+ if (enable_ints)
+ local_irq_disable();
+ spin_lock(&ehci->lock);
}
static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
--
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