We've just converted pciehp to threaded IRQ handling, but still cannot
sleep in pciehp_ist() because the function is also called in poll mode,
which runs in softirq context (from a timer).
Convert poll mode to a kthread so that pciehp_ist() always runs in task
context.
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
drivers/pci/hotplug/pciehp.h | 4 +-
drivers/pci/hotplug/pciehp_hpc.c | 67 +++++++++++++++-----------------
2 files changed, 34 insertions(+), 37 deletions(-)
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index ab1d97a1822d..9f11360e3318 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -97,7 +97,7 @@ struct event_info {
* used for synchronous writes to the Slot Control register
* @slot_cap: cached copy of the Slot Capabilities register
* @slot_ctrl: cached copy of the Slot Control register
- * @poll_timer: timer to poll for slot events if no IRQ is available,
+ * @poll_thread: thread to poll for slot events if no IRQ is available,
* enabled with pciehp_poll_mode module parameter
* @cmd_started: jiffies when the Slot Control register was last written;
* the next write is allowed 1 second later, absent a Command Completed
@@ -122,7 +122,7 @@ struct controller {
wait_queue_head_t queue;
u32 slot_cap;
u16 slot_ctrl;
- struct timer_list poll_timer;
+ struct task_struct *poll_thread;
unsigned long cmd_started; /* jiffies */
unsigned int cmd_busy:1;
unsigned int link_active_reporting:1;
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 5f41ba788cb2..be4d9698f254 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -17,7 +17,7 @@
#include <linux/types.h>
#include <linux/signal.h>
#include <linux/jiffies.h>
-#include <linux/timer.h>
+#include <linux/kthread.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/time.h>
@@ -33,43 +33,17 @@ static inline struct pci_dev *ctrl_dev(struct controller *ctrl)
static irqreturn_t pciehp_isr(int irq, void *dev_id);
static irqreturn_t pciehp_ist(int irq, void *dev_id);
-static void start_int_poll_timer(struct controller *ctrl, int sec);
-
-/* This is the interrupt polling timeout function. */
-static void int_poll_timeout(struct timer_list *t)
-{
- struct controller *ctrl = from_timer(ctrl, t, poll_timer);
-
- /* Poll for interrupt events. regs == NULL => polling */
- while (pciehp_isr(IRQ_NOTCONNECTED, ctrl) == IRQ_WAKE_THREAD)
- pciehp_ist(IRQ_NOTCONNECTED, ctrl);
-
- if (!pciehp_poll_time)
- pciehp_poll_time = 2; /* default polling interval is 2 sec */
-
- start_int_poll_timer(ctrl, pciehp_poll_time);
-}
-
-/* This function starts the interrupt polling timer. */
-static void start_int_poll_timer(struct controller *ctrl, int sec)
-{
- /* Clamp to sane value */
- if ((sec <= 0) || (sec > 60))
- sec = 2;
-
- ctrl->poll_timer.expires = jiffies + sec * HZ;
- add_timer(&ctrl->poll_timer);
-}
+static int pciehp_poll(void *data);
static inline int pciehp_request_irq(struct controller *ctrl)
{
int retval, irq = ctrl->pcie->irq;
- /* Install interrupt polling timer. Start with 10 sec delay */
if (pciehp_poll_mode) {
- timer_setup(&ctrl->poll_timer, int_poll_timeout, 0);
- start_int_poll_timer(ctrl, 10);
- return 0;
+ ctrl->poll_thread = kthread_run(&pciehp_poll, ctrl,
+ "pciehp_poll-%s",
+ slot_name(ctrl->slot));
+ return PTR_ERR_OR_ZERO(ctrl->poll_thread);
}
/* Installs the interrupt handler */
@@ -84,7 +58,7 @@ static inline int pciehp_request_irq(struct controller *ctrl)
static inline void pciehp_free_irq(struct controller *ctrl)
{
if (pciehp_poll_mode)
- del_timer_sync(&ctrl->poll_timer);
+ kthread_stop(ctrl->poll_thread);
else
free_irq(ctrl->pcie->irq, ctrl);
}
@@ -652,6 +626,29 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static int pciehp_poll(void *data)
+{
+ struct controller *ctrl = data;
+
+ schedule_timeout_idle(10 * HZ); /* start with 10 sec delay */
+
+ while (!kthread_should_stop()) {
+ if (kthread_should_park())
+ kthread_parkme();
+
+ /* poll for interrupt events */
+ while (pciehp_isr(IRQ_NOTCONNECTED, ctrl) == IRQ_WAKE_THREAD)
+ pciehp_ist(IRQ_NOTCONNECTED, ctrl);
+
+ if (pciehp_poll_time <= 0 || pciehp_poll_time > 60)
+ pciehp_poll_time = 2; /* clamp to sane value */
+
+ schedule_timeout_idle(pciehp_poll_time * HZ);
+ }
+
+ return 0;
+}
+
static void pcie_enable_notification(struct controller *ctrl)
{
u16 cmd, mask;
@@ -742,7 +739,7 @@ int pciehp_reset_slot(struct slot *slot, int probe)
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, 0);
if (pciehp_poll_mode)
- del_timer_sync(&ctrl->poll_timer);
+ kthread_park(ctrl->poll_thread);
pci_reset_bridge_secondary_bus(ctrl->pcie->port);
@@ -751,7 +748,7 @@ int pciehp_reset_slot(struct slot *slot, int probe)
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, ctrl_mask);
if (pciehp_poll_mode)
- int_poll_timeout(&ctrl->poll_timer);
+ kthread_unpark(ctrl->poll_thread);
return 0;
}
--
2.17.1
