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PCI: pciehp: Handle events synchronously

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Up until now, pciehp's IRQ handler schedules a work item for each event,
which in turn schedules a work item to enable or disable the slot.  This
double indirection was necessary because sleeping wasn't allowed in the
IRQ handler.

However it is now that pciehp has been converted to threaded IRQ handling
and polling, so handle events synchronously in pciehp_ist() and remove
the work item infrastructure (with the exception of work items to handle
a button press after the 5 second delay).

For link or presence change events, move the register read to determine
the current link or presence state behind acquisition of the slot lock
to prevent it from becoming stale while the lock is contended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Lukas Wunner
2018-07-19 17:27:41 -05:00
committed by Bjorn Helgaas
parent b0ccd9dd5d
commit 0e94916e60
3 changed files with 67 additions and 158 deletions
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27
drivers/pci/hotplug/pciehp_hpc.c
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@@ -581,8 +581,6 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id)
struct controller *ctrl = (struct controller *)dev_id;
struct slot *slot = ctrl->slot;
u32 events;
u8 present;
bool link;
synchronize_hardirq(irq);
events = atomic_xchg(&ctrl->pending_events, 0);
@@ -593,34 +591,25 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id)
if (events & PCI_EXP_SLTSTA_ABP) {
ctrl_info(ctrl, "Slot(%s): Attention button pressed\n",
slot_name(slot));
pciehp_queue_interrupt_event(slot, INT_BUTTON_PRESS);
pciehp_handle_button_press(slot);
}
/*
* Check Link Status Changed at higher precedence than Presence
* Detect Changed. The PDS value may be set to "card present" from
* out-of-band detection, which may be in conflict with a Link Down
* and cause the wrong event to queue.
* out-of-band detection, which may be in conflict with a Link Down.
*/
if (events & PCI_EXP_SLTSTA_DLLSC) {
link = pciehp_check_link_active(ctrl);
ctrl_info(ctrl, "Slot(%s): Link %s\n", slot_name(slot),
link ? "Up" : "Down");
pciehp_queue_interrupt_event(slot, link ? INT_LINK_UP :
INT_LINK_DOWN);
} else if (events & PCI_EXP_SLTSTA_PDC) {
pciehp_get_adapter_status(slot, &present);
ctrl_info(ctrl, "Slot(%s): Card %spresent\n", slot_name(slot),
present ? "" : "not ");
pciehp_queue_interrupt_event(slot, present ? INT_PRESENCE_ON :
INT_PRESENCE_OFF);
}
if (events & PCI_EXP_SLTSTA_DLLSC)
pciehp_handle_link_change(slot);
else if (events & PCI_EXP_SLTSTA_PDC)
pciehp_handle_presence_change(slot);
/* Check Power Fault Detected */
if ((events & PCI_EXP_SLTSTA_PFD) && !ctrl->power_fault_detected) {
ctrl->power_fault_detected = 1;
ctrl_err(ctrl, "Slot(%s): Power fault\n", slot_name(slot));
pciehp_queue_interrupt_event(slot, INT_POWER_FAULT);
pciehp_set_attention_status(slot, 1);
pciehp_green_led_off(slot);
}
return IRQ_HANDLED;