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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>,
	linux-pci@vger.kernel.org, Yinghai Lu <yinghai@kernel.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH] Revert "PCI: Remove from bus_list and release resources in pci_release_dev()"
Date: Sat, 01 Feb 2014 00:34:15 +0100	[thread overview]
Message-ID: <1676758.QjUXk2223P@vostro.rjw.lan> (raw)
In-Reply-To: <20140130131236.GW18029@intel.com>

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    
Revert commit ef83b0781a73 "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 ef83b0781a73 attempted to address
cannot happen any more after commit 8a4c5c329de7 "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.

Fixes: ef83b0781a73 (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>

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 04796c056d12..6e34498ec9f0 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -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);
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 4ff36bfa785e..b8c93c90daf5 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -3,6 +3,20 @@
 #include <linux/pci-aspm.h>
 #include "pci.h"
 
+static void pci_free_resources(struct pci_dev *dev)
+{
+	int i;
+
+	msi_remove_pci_irq_vectors(dev);
+
+	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 +39,11 @@ 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);
 }
 


       reply	other threads:[~2014-01-31 23:19 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20140130131236.GW18029@intel.com>
2014-01-31 23:34 ` Rafael J. Wysocki [this message]
2014-02-01  1:56   ` Yinghai Lu
2014-02-01 14:38     ` Rafael J. Wysocki
2014-02-01 18:23       ` Linus Torvalds
2014-02-01 18:48       ` Mika Westerberg

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