Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 20 Jun 2023 10:49:14 +0100 (BST)
From:   "Maciej W. Rozycki" <macro@orcam.me.uk>
To:     Bjorn Helgaas <bhelgaas@google.com>,
        Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Leon Romanovsky <leon@kernel.org>
cc:     linux-pci@vger.kernel.org, linux-rdma@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] PCI: Export pci_parent_bus_reset() for drivers to use
In-Reply-To: <alpine.DEB.2.21.2306200153110.14084@angie.orcam.me.uk>
Message-ID: <alpine.DEB.2.21.2306200231020.14084@angie.orcam.me.uk>
References: <alpine.DEB.2.21.2306200153110.14084@angie.orcam.me.uk>
User-Agent: Alpine 2.21 (DEB 202 2017-01-01)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Precedence: bulk

Export pci_parent_bus_reset() so that drivers do not duplicate it.  
Document the interface.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
---
 drivers/pci/pci.c   |   15 ++++++++++++++-
 include/linux/pci.h |    1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

linux-pci-parent-bus-reset-export.diff
Index: linux-macro/drivers/pci/pci.c
===================================================================
--- linux-macro.orig/drivers/pci/pci.c
+++ linux-macro/drivers/pci/pci.c
@@ -5149,7 +5149,19 @@ int pci_bridge_secondary_bus_reset(struc
 }
 EXPORT_SYMBOL_GPL(pci_bridge_secondary_bus_reset);
 
-static int pci_parent_bus_reset(struct pci_dev *dev, bool probe)
+/**
+ * pci_parent_bus_reset - Reset a device via its upstream PCI bridge
+ * @dev: Device to reset.
+ * @probe: Only check if reset is possible if TRUE, actually reset if FALSE.
+ *
+ * Perform a device reset by requesting a secondary bus reset via the
+ * device's immediate upstream PCI bridge.  Return 0 if successful or
+ * -ENOTTY if the reset failed or it could not have been issued in the
+ * first place because the device is not on a secondary bus of any PCI
+ * bridge or it wouldn't be the only device reset.  If probing, then
+ * only verify whether it would be possible to issue a reset.
+ */
+int pci_parent_bus_reset(struct pci_dev *dev, bool probe)
 {
 	struct pci_dev *pdev;
 
@@ -5166,6 +5178,7 @@ static int pci_parent_bus_reset(struct p
 
 	return pci_bridge_secondary_bus_reset(dev->bus->self);
 }
+EXPORT_SYMBOL_GPL(pci_parent_bus_reset);
 
 static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, bool probe)
 {
Index: linux-macro/include/linux/pci.h
===================================================================
--- linux-macro.orig/include/linux/pci.h
+++ linux-macro/include/linux/pci.h
@@ -1447,6 +1447,7 @@ int devm_request_pci_bus_resources(struc
 
 /* Temporary until new and working PCI SBR API in place */
 int pci_bridge_secondary_bus_reset(struct pci_dev *dev);
+int pci_parent_bus_reset(struct pci_dev *dev, bool probe);
 
 #define __pci_bus_for_each_res0(bus, res, ...)				\
 	for (unsigned int __b = 0;					\