linux-kernel - [PATCH v1 2/2] PCI: Remove redundant probes for device reset support

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Date:   Fri, 16 Feb 2018 16:50:18 -0600
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     linux-pci@...r.kernel.org
Cc:     Jayachandran Nair <Jayachandran.Nair@...ium.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        linux-kernel@...r.kernel.org,
        Alex Williamson <alex.williamson@...hat.com>,
        Robert Richter <Robert.Richter@...ium.com>,
        Tom Vaden <tom.vaden@....com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        George Cherian <george.cherian@...ium.com>
Subject: [PATCH v1 2/2] PCI: Remove redundant probes for device reset support

From: Bjorn Helgaas <bhelgaas@...gle.com>

We probe every device for whether it supports reset so we can tell whether
to create a sysfs "reset" file for it.  We do that probe in
pci_init_capabilities() during enumeration and save the result in
dev->reset_fn.  The result doesn't depend on any other devices on the bus
and shouldn't change after boot, so we don't need to do the probe again.

Remove the pci_probe_reset_function() calls and rely on the dev->reset_fn
we found during enumeration.  No functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
---
 drivers/pci/pci.c |   15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f6a4dd10d9b0..4db740e4f50a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4450,9 +4450,8 @@ int pci_reset_function(struct pci_dev *dev)
 {
 	int rc;
 
-	rc = pci_probe_reset_function(dev);
-	if (rc)
-		return rc;
+	if (!dev->reset_fn)
+		return -ENOTTY;
 
 	pci_dev_lock(dev);
 	pci_dev_save_and_disable(dev);
@@ -4487,9 +4486,8 @@ int pci_reset_function_locked(struct pci_dev *dev)
 {
 	int rc;
 
-	rc = pci_probe_reset_function(dev);
-	if (rc)
-		return rc;
+	if (!dev->reset_fn)
+		return -ENOTTY;
 
 	pci_dev_save_and_disable(dev);
 
@@ -4511,9 +4509,8 @@ int pci_try_reset_function(struct pci_dev *dev)
 {
 	int rc;
 
-	rc = pci_probe_reset_function(dev);
-	if (rc)
-		return rc;
+	if (!dev->reset_fn)
+		return -ENOTTY;
 
 	if (!pci_dev_trylock(dev))
 		return -EAGAIN;