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authorAlan Stern <stern@rowland.harvard.edu>2012-07-11 19:23:16 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-17 03:56:48 +0400
commit43fe3a99d9caf10b25f9c596e9854cdae30db418 (patch)
tree596812dcd61ba9cbffe0e837d53dd3a2232ad214 /drivers/usb/host/ehci-hub.c
parentc4f3476436f7452b97c8accb5dd7d53219a11a3f (diff)
downloadlinux-43fe3a99d9caf10b25f9c596e9854cdae30db418.tar.xz
USB: EHCI: resolve some unlikely races
This patch (as1589) resolves some unlikely races involving system shutdown or controller death in ehci-hcd: Shutdown races with both root-hub resume and controller resume. Controller death races with root-hub suspend. A new bitflag is added to indicate that the controller has been shut down (whether for system shutdown or because it died). Tests are added in the suspend and resume pathways to avoid reactivating the controller after any sort of shutdown. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci-hub.c')
-rw-r--r--drivers/usb/host/ehci-hub.c27
1 files changed, 23 insertions, 4 deletions
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index ffc5f27df725..c7880223738a 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -221,6 +221,8 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
ehci_quiesce(ehci);
spin_lock_irq (&ehci->lock);
+ if (ehci->rh_state < EHCI_RH_RUNNING)
+ goto done;
/* Once the controller is stopped, port resumes that are already
* in progress won't complete. Hence if remote wakeup is enabled
@@ -306,6 +308,10 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
ehci_halt (ehci);
spin_lock_irq(&ehci->lock);
+ if (ehci->enabled_hrtimer_events & BIT(EHCI_HRTIMER_POLL_DEAD))
+ ehci_handle_controller_death(ehci);
+ if (ehci->rh_state != EHCI_RH_RUNNING)
+ goto done;
ehci->rh_state = EHCI_RH_SUSPENDED;
end_unlink_async(ehci);
@@ -320,6 +326,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
ehci_writel(ehci, mask, &ehci->regs->intr_enable);
ehci_readl(ehci, &ehci->regs->intr_enable);
+ done:
ehci->next_statechange = jiffies + msecs_to_jiffies(10);
ehci->enabled_hrtimer_events = 0;
ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;
@@ -342,10 +349,8 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
if (time_before (jiffies, ehci->next_statechange))
msleep(5);
spin_lock_irq (&ehci->lock);
- if (!HCD_HW_ACCESSIBLE(hcd)) {
- spin_unlock_irq(&ehci->lock);
- return -ESHUTDOWN;
- }
+ if (!HCD_HW_ACCESSIBLE(hcd) || ehci->shutdown)
+ goto shutdown;
if (unlikely(ehci->debug)) {
if (!dbgp_reset_prep())
@@ -384,6 +389,8 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
spin_unlock_irq(&ehci->lock);
msleep(8);
spin_lock_irq(&ehci->lock);
+ if (ehci->shutdown)
+ goto shutdown;
/* clear phy low-power mode before resume */
if (ehci->bus_suspended && ehci->has_hostpc) {
@@ -401,6 +408,8 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
spin_unlock_irq(&ehci->lock);
msleep(5);
spin_lock_irq(&ehci->lock);
+ if (ehci->shutdown)
+ goto shutdown;
}
/* manually resume the ports we suspended during bus_suspend() */
@@ -421,6 +430,8 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
spin_unlock_irq(&ehci->lock);
msleep(20);
spin_lock_irq(&ehci->lock);
+ if (ehci->shutdown)
+ goto shutdown;
}
i = HCS_N_PORTS (ehci->hcs_params);
@@ -439,10 +450,18 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
ehci_handover_companion_ports(ehci);
/* Now we can safely re-enable irqs */
+ spin_lock_irq(&ehci->lock);
+ if (ehci->shutdown)
+ goto shutdown;
ehci_writel(ehci, INTR_MASK, &ehci->regs->intr_enable);
(void) ehci_readl(ehci, &ehci->regs->intr_enable);
+ spin_unlock_irq(&ehci->lock);
return 0;
+
+ shutdown:
+ spin_unlock_irq(&ehci->lock);
+ return -ESHUTDOWN;
}
#else