[2/7] PCI/DPC: Defer event handling to work queue

Message ID 20180620213833.25072-2-keith.busch@intel.com
State New
Delegated to: Bjorn Helgaas
Headers show
Series
  • [1/7] PCI/DPC: Leave interrupts enabled while handling event
Related show

Commit Message

Keith Busch June 20, 2018, 9:38 p.m.
This moves all event handling to the existing work queue, which will
make passing event information simpler to the handler.

Signed-off-by: Keith Busch <keith.busch@intel.com>
---
 drivers/pci/pcie/dpc.c | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

Comments

Christoph Hellwig June 21, 2018, 7:27 a.m. | #1
On Wed, Jun 20, 2018 at 03:38:28PM -0600, Keith Busch wrote:
> This moves all event handling to the existing work queue, which will
> make passing event information simpler to the handler.

I wonder if just using a threaded interrupt would be useful for
the DPC handler?
Christoph Hellwig June 21, 2018, 7:28 a.m. | #2
On Thu, Jun 21, 2018 at 12:27:27AM -0700, Christoph Hellwig wrote:
> On Wed, Jun 20, 2018 at 03:38:28PM -0600, Keith Busch wrote:
> > This moves all event handling to the existing work queue, which will
> > make passing event information simpler to the handler.
> 
> I wonder if just using a threaded interrupt would be useful for
> the DPC handler?

Ok, I should have read until the end of the thread first..
Keith Busch June 21, 2018, 1:58 p.m. | #3
On Thu, Jun 21, 2018 at 12:28:19AM -0700, Christoph Hellwig wrote:
> On Thu, Jun 21, 2018 at 12:27:27AM -0700, Christoph Hellwig wrote:
> > On Wed, Jun 20, 2018 at 03:38:28PM -0600, Keith Busch wrote:
> > > This moves all event handling to the existing work queue, which will
> > > make passing event information simpler to the handler.
> > 
> > I wonder if just using a threaded interrupt would be useful for
> > the DPC handler?
> 
> Ok, I should have read until the end of the thread first..

It's still good to know the series was on the right path. :)

Patch

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 972aac892846..5f5fac279c75 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -108,14 +108,6 @@  static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
 	return PCI_ERS_RESULT_RECOVERED;
 }
 
-static void dpc_work(struct work_struct *work)
-{
-	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
-	struct pci_dev *pdev = dpc->dev->port;
-
-	/* We configure DPC so it only triggers on ERR_FATAL */
-	pcie_do_fatal_recovery(pdev, PCIE_PORT_SERVICE_DPC);
-}
 
 static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
 {
@@ -174,33 +166,21 @@  static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
 	}
 }
 
-static irqreturn_t dpc_irq(int irq, void *context)
+static void dpc_work(struct work_struct *work)
 {
-	struct dpc_dev *dpc = (struct dpc_dev *)context;
+	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
 	struct pci_dev *pdev = dpc->dev->port;
 	struct device *dev = &dpc->dev->device;
 	u16 cap = dpc->cap_pos, status, source, reason, ext_reason;
 
 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
-
-	if (!(status & PCI_EXP_DPC_STATUS_INTERRUPT) || status == (u16)(~0))
-		return IRQ_NONE;
-
-	if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
-		pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
-				      PCI_EXP_DPC_STATUS_INTERRUPT);
-		return IRQ_HANDLED;
-	}
-
-	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID,
-			     &source);
+	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
 
 	dev_info(dev, "DPC containment event, status:%#06x source:%#06x\n",
-		status, source);
+		 status, source);
 
 	reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
 	ext_reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT) >> 5;
-
 	dev_warn(dev, "DPC %s detected, remove downstream devices\n",
 		 (reason == 0) ? "unmasked uncorrectable error" :
 		 (reason == 1) ? "ERR_NONFATAL" :
@@ -208,10 +188,26 @@  static irqreturn_t dpc_irq(int irq, void *context)
 		 (ext_reason == 0) ? "RP PIO error" :
 		 (ext_reason == 1) ? "software trigger" :
 				     "reserved error");
+
 	/* show RP PIO error detail information */
 	if (dpc->rp_extensions && reason == 3 && ext_reason == 0)
 		dpc_process_rp_pio_error(dpc);
 
+	/* We configure DPC so it only triggers on ERR_FATAL */
+	pcie_do_fatal_recovery(pdev, PCIE_PORT_SERVICE_DPC);
+}
+
+static irqreturn_t dpc_irq(int irq, void *context)
+{
+	struct dpc_dev *dpc = (struct dpc_dev *)context;
+	struct pci_dev *pdev = dpc->dev->port;
+	u16 cap = dpc->cap_pos, status;
+
+	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
+
+	if (!(status & PCI_EXP_DPC_STATUS_INTERRUPT) || status == (u16)(~0))
+		return IRQ_NONE;
+
 	pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
 			      PCI_EXP_DPC_STATUS_INTERRUPT);
 	if (status & PCI_EXP_DPC_STATUS_TRIGGER)