linux-kernel - [PATCH V3 1/6] PCI: Protect restore with device lock to be consistent

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Message-Id: <1514912423-13341-2-git-send-email-okaya@codeaurora.org>
Date:   Tue,  2 Jan 2018 12:00:18 -0500
From:   Sinan Kaya <okaya@...eaurora.org>
To:     linux-pci@...r.kernel.org, timur@...eaurora.org
Cc:     linux-arm-msm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Sinan Kaya <okaya@...eaurora.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH V3 1/6] PCI: Protect restore with device lock to be consistent

Commit b014e96d1abb ("PCI: Protect pci_error_handlers->reset_notify() usage
with device_lock()") added protection around pci_dev_restore() function so
that device specific remove callback does not cause a race condition
against hotplug.

pci_dev_lock() usage has been forgotten in two different places in the
code. Adding locks for pci_slot_restore() and moving pci_dev_restore()
inside the locks for pci_try_reset_function().

Signed-off-by: Sinan Kaya <okaya@...eaurora.org>
Reviewed-by: Christoph Hellwig <hch@....de>
---
 drivers/pci/pci.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 764ca7b..463b32d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4448,9 +4448,9 @@ int pci_try_reset_function(struct pci_dev *dev)
 
 	pci_dev_save_and_disable(dev);
 	rc = __pci_reset_function_locked(dev);
+	pci_dev_restore(dev);
 	pci_dev_unlock(dev);
 
-	pci_dev_restore(dev);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(pci_try_reset_function);
@@ -4658,7 +4658,9 @@ static void pci_slot_restore(struct pci_slot *slot)
 	list_for_each_entry(dev, &slot->bus->devices, bus_list) {
 		if (!dev->slot || dev->slot != slot)
 			continue;
+		pci_dev_lock(dev);
 		pci_dev_restore(dev);
+		pci_dev_unlock(dev);
 		if (dev->subordinate)
 			pci_bus_restore(dev->subordinate);
 	}
-- 
1.9.1