From 43fe3a99d9caf10b25f9c596e9854cdae30db418 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 11 Jul 2012 11:23:16 -0400 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-hcd.c | 20 +++++++++++++++++++- drivers/usb/host/ehci-hub.c | 27 +++++++++++++++++++++++---- drivers/usb/host/ehci.h | 1 + 3 files changed, 43 insertions(+), 5 deletions(-) diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index ac4c8dd..e44ca54 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -343,6 +343,7 @@ static void ehci_shutdown(struct usb_hcd *hcd) struct ehci_hcd *ehci = hcd_to_ehci(hcd); spin_lock_irq(&ehci->lock); + ehci->shutdown = true; ehci->rh_state = EHCI_RH_STOPPING; ehci->enabled_hrtimer_events = 0; spin_unlock_irq(&ehci->lock); @@ -823,6 +824,7 @@ dead: usb_hc_died(hcd); /* Don't let the controller do anything more */ + ehci->shutdown = true; ehci->rh_state = EHCI_RH_STOPPING; ehci->command &= ~(CMD_RUN | CMD_ASE | CMD_PSE); ehci_writel(ehci, ehci->command, &ehci->regs->command); @@ -1129,6 +1131,9 @@ static int __maybe_unused ehci_resume(struct usb_hcd *hcd, bool hibernated) /* Mark hardware accessible again as we are back to full power by now */ set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags); + if (ehci->shutdown) + return 0; /* Controller is dead */ + /* * If CF is still set and we aren't resuming from hibernation * then we maintained suspend power. @@ -1139,10 +1144,17 @@ static int __maybe_unused ehci_resume(struct usb_hcd *hcd, bool hibernated) int mask = INTR_MASK; ehci_prepare_ports_for_controller_resume(ehci); + + spin_lock_irq(&ehci->lock); + if (ehci->shutdown) + goto skip; + if (!hcd->self.root_hub->do_remote_wakeup) mask &= ~STS_PCD; ehci_writel(ehci, mask, &ehci->regs->intr_enable); ehci_readl(ehci, &ehci->regs->intr_enable); + skip: + spin_unlock_irq(&ehci->lock); return 0; } @@ -1154,14 +1166,20 @@ static int __maybe_unused ehci_resume(struct usb_hcd *hcd, bool hibernated) (void) ehci_halt(ehci); (void) ehci_reset(ehci); + spin_lock_irq(&ehci->lock); + if (ehci->shutdown) + goto skip; + ehci_writel(ehci, ehci->command, &ehci->regs->command); ehci_writel(ehci, FLAG_CF, &ehci->regs->configured_flag); ehci_readl(ehci, &ehci->regs->command); /* unblock posted writes */ + ehci->rh_state = EHCI_RH_SUSPENDED; + spin_unlock_irq(&ehci->lock); + /* here we "know" root ports should always stay powered */ ehci_port_power(ehci, 1); - ehci->rh_state = EHCI_RH_SUSPENDED; return 1; } diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c index ffc5f27..c788022 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 diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h index 7de58fe..da07d98 100644 --- a/drivers/usb/host/ehci.h +++ b/drivers/usb/host/ehci.h @@ -118,6 +118,7 @@ struct ehci_hcd { /* one per controller */ bool need_rescan:1; bool intr_unlinking:1; bool async_unlinking:1; + bool shutdown:1; struct ehci_qh *qh_scan_next; /* async schedule support */ -- 2.7.4