Revert "PCI: Remove from bus_list and release resources in pci_release_dev()" (04480094) · Commits · 戴 / test

Revert commit "PCI: Remove from bus_list and release resources in pci_release_dev()" that made some nasty race conditions become possible. For example, if a Thunderbolt link is unplugged and then replugged immediately, the pci_release_dev() resulting from the hot-remove code path may be racing with the hot-add code path which after that commit causes various kinds of breakage to happen (up to and including a hard crash of the whole system). Moreover, the problem that commit attempted to address cannot happen any more after commit "PCI: Check parent kobject in pci_destroy_dev()", because pci_destroy_dev() will now return immediately if it has already been executed for the given device. Note, however, that the invocation of msi_remove_pci_irq_vectors() removed by commit from pci_free_resources() along with the other changes made by it is not added back because of subsequent code changes depending on that modification. Fixes: (PCI: Remove from bus_list and release resources in pci_release_dev()) Reported-by:

Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/pci/probe.c

+2 −19

Original line number	Diff line number	Diff line
		@@ -1208,18 +1208,6 @@ static void pci_release_capabilities(struct pci_dev *dev)
		pci_free_cap_save_buffers(dev);
		}

		static void pci_free_resources(struct pci_dev *dev)
		{
		int i;

		pci_cleanup_rom(dev);
		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
		struct resource *res = dev->resource + i;
		if (res->parent)
		release_resource(res);
		}
		}

		/**
		* pci_release_dev - free a pci device structure when all users of it are finished.
		* @dev: device that's been disconnected
		@@ -1229,14 +1217,9 @@ static void pci_free_resources(struct pci_dev *dev)
		*/
		static void pci_release_dev(struct device *dev)
		{
		struct pci_dev *pci_dev = to_pci_dev(dev);

		down_write(&pci_bus_sem);
		list_del(&pci_dev->bus_list);
		up_write(&pci_bus_sem);

		pci_free_resources(pci_dev);
		struct pci_dev *pci_dev;

		pci_dev = to_pci_dev(dev);
		pci_release_capabilities(pci_dev);
		pci_release_of_node(pci_dev);
		pcibios_release_device(pci_dev);

drivers/pci/remove.c

+17 −0

Original line number	Diff line number	Diff line
		@@ -3,6 +3,18 @@
		#include <linux/pci-aspm.h>
		#include "pci.h"

		static void pci_free_resources(struct pci_dev *dev)
		{
		int i;

		pci_cleanup_rom(dev);
		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
		struct resource *res = dev->resource + i;
		if (res->parent)
		release_resource(res);
		}
		}

		static void pci_stop_dev(struct pci_dev *dev)
		{
		pci_pme_active(dev, false);
		@@ -25,6 +37,11 @@ static void pci_destroy_dev(struct pci_dev *dev)

		device_del(&dev->dev);

		down_write(&pci_bus_sem);
		list_del(&dev->bus_list);
		up_write(&pci_bus_sem);

		pci_free_resources(dev);
		put_device(&dev->dev);
		}

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