PCI: pciehp: Don't re-read Slot Status when queuing hotplug event

Previously we read Slot Status to learn about hotplug events, then cleared
the events, then re-read Slot Status to find out what happened.  But Slot
Status might have changed before the second read.

Capture the Slot Status once before clearing the events.  Also capture the
Link Status if we had a link status change.

[bhelgaas: changelog, split to separate patch]
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Mayurkumar Patel <mayurkumar.patel@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 625fa6a2f3ab38c73a2f53fa7e2a1385c093e88a..fe99b45c592558e4f70ed0f5c01371452db213c1 100644 (file)
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -566,6 +566,10 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id)
        if (!events)
                return IRQ_NONE;
 
+       /* Capture link status before clearing interrupts */
+       if (events & PCI_EXP_SLTSTA_DLLSC)
+               link = pciehp_check_link_active(ctrl);
+
        pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, events);
        ctrl_dbg(ctrl, "pending interrupts %#06x from Slot Status\n", events);
 
@@ -598,7 +602,7 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id)
 
        /* Check Presence Detect Changed */
        if (events & PCI_EXP_SLTSTA_PDC) {
-               pciehp_get_adapter_status(slot, &present);
+               present = !!(status & PCI_EXP_SLTSTA_PDS);
                ctrl_info(ctrl, "Card %spresent on Slot(%s)\n",
                          present ? "" : "not ", slot_name(slot));
                pciehp_queue_interrupt_event(slot, present ? INT_PRESENCE_ON :
@@ -613,7 +617,6 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id)
        }
 
        if (events & PCI_EXP_SLTSTA_DLLSC) {
-               link = pciehp_check_link_active(ctrl);
                ctrl_info(ctrl, "slot(%s): Link %s event\n",
                          slot_name(slot), link ? "Up" : "Down");
                pciehp_queue_interrupt_event(slot, link ? INT_LINK_UP :