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From:   Benjamin Herrenschmidt <benh@kernel.crashing.org>
To:     Bjorn Helgaas <helgaas@kernel.org>, linux-pci@vger.kernel.org
Cc:     Hari Vyas <hari.vyas@broadcom.com>, Ray Jui <ray.jui@broadcom.com>,
        Srinath Mannam <srinath.mannam@broadcom.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Jens Axboe <axboe@kernel.dk>, Lukas Wunner <lukas@wunner.de>,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
        Marta Rybczynska <mrybczyn@kalray.eu>,
        Pierre-Yves Kerbrat <pkerbrat@kalray.eu>,
        linux-kernel@vger.kernel.org,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: [RFC PATCH 1/6] Revert "PCI: Fix is_added/is_busmaster race condition"
Date:   Fri, 17 Aug 2018 14:48:57 +1000
Message-Id: <20180817044902.31420-2-benh@kernel.crashing.org>
In-Reply-To: <20180817044902.31420-1-benh@kernel.crashing.org>
References: <20180817044902.31420-1-benh@kernel.crashing.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This reverts commit 44bda4b7d26e9fffed6d7152d98a2e9edaeb2a76.

The new pci state mutex provides a simpler way of addressing
this race and avoids the relative includes added to the powerpc
code.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 arch/powerpc/kernel/pci-common.c          |  4 +---
 arch/powerpc/platforms/powernv/pci-ioda.c |  3 +--
 arch/powerpc/platforms/pseries/setup.c    |  3 +--
 drivers/pci/bus.c                         |  6 +++---
 drivers/pci/hotplug/acpiphp_glue.c        |  2 +-
 drivers/pci/pci.h                         | 11 -----------
 drivers/pci/probe.c                       |  4 ++--
 drivers/pci/remove.c                      |  5 ++---
 include/linux/pci.h                       |  1 +
 9 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 471aac313b89..fe9733ffffaa 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -42,8 +42,6 @@
 #include <asm/ppc-pci.h>
 #include <asm/eeh.h>
 
-#include "../../../drivers/pci/pci.h"
-
 /* hose_spinlock protects accesses to the the phb_bitmap. */
 static DEFINE_SPINLOCK(hose_spinlock);
 LIST_HEAD(hose_list);
@@ -1016,7 +1014,7 @@ void pcibios_setup_bus_devices(struct pci_bus *bus)
 		/* Cardbus can call us to add new devices to a bus, so ignore
 		 * those who are already fully discovered
 		 */
-		if (pci_dev_is_added(dev))
+		if (dev->is_added)
 			continue;
 
 		pcibios_setup_device(dev);
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 70b2e1e0f23c..5bd0eb6681bc 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -46,7 +46,6 @@
 
 #include "powernv.h"
 #include "pci.h"
-#include "../../../../drivers/pci/pci.h"
 
 #define PNV_IODA1_M64_NUM	16	/* Number of M64 BARs	*/
 #define PNV_IODA1_M64_SEGS	8	/* Segments per M64 BAR	*/
@@ -3139,7 +3138,7 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
 	struct pci_dn *pdn;
 	int mul, total_vfs;
 
-	if (!pdev->is_physfn || pci_dev_is_added(pdev))
+	if (!pdev->is_physfn || pdev->is_added)
 		return;
 
 	pdn = pci_get_pdn(pdev);
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 8a4868a3964b..139f0af6c3d9 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -71,7 +71,6 @@
 #include <asm/security_features.h>
 
 #include "pseries.h"
-#include "../../../../drivers/pci/pci.h"
 
 int CMO_PrPSP = -1;
 int CMO_SecPSP = -1;
@@ -665,7 +664,7 @@ static void pseries_pci_fixup_iov_resources(struct pci_dev *pdev)
 	const int *indexes;
 	struct device_node *dn = pci_device_to_OF_node(pdev);
 
-	if (!pdev->is_physfn || pci_dev_is_added(pdev))
+	if (!pdev->is_physfn || pdev->is_added)
 		return;
 	/*Firmware must support open sriov otherwise dont configure*/
 	indexes = of_get_property(dn, "ibm,open-sriov-vf-bar-info", NULL);
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 5cb40b2518f9..35b7fc87eac5 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -330,7 +330,7 @@ void pci_bus_add_device(struct pci_dev *dev)
 		return;
 	}
 
-	pci_dev_assign_added(dev, true);
+	dev->is_added = 1;
 }
 EXPORT_SYMBOL_GPL(pci_bus_add_device);
 
@@ -347,14 +347,14 @@ void pci_bus_add_devices(const struct pci_bus *bus)
 
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		/* Skip already-added devices */
-		if (pci_dev_is_added(dev))
+		if (dev->is_added)
 			continue;
 		pci_bus_add_device(dev);
 	}
 
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		/* Skip if device attach failed */
-		if (!pci_dev_is_added(dev))
+		if (!dev->is_added)
 			continue;
 		child = dev->subordinate;
 		if (child)
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index ef0b1b6ba86f..3a17b290df5d 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -509,7 +509,7 @@ static void enable_slot(struct acpiphp_slot *slot)
 
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		/* Assume that newly added devices are powered on already. */
-		if (!pci_dev_is_added(dev))
+		if (!dev->is_added)
 			dev->current_state = PCI_D0;
 	}
 
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6e0d1528d471..473aa10a5dbf 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -295,7 +295,6 @@ struct pci_sriov {
 
 /* pci_dev priv_flags */
 #define PCI_DEV_DISCONNECTED 0
-#define PCI_DEV_ADDED 1
 
 static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)
 {
@@ -308,16 +307,6 @@ static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
 	return test_bit(PCI_DEV_DISCONNECTED, &dev->priv_flags);
 }
 
-static inline void pci_dev_assign_added(struct pci_dev *dev, bool added)
-{
-	assign_bit(PCI_DEV_ADDED, &dev->priv_flags, added);
-}
-
-static inline bool pci_dev_is_added(const struct pci_dev *dev)
-{
-	return test_bit(PCI_DEV_ADDED, &dev->priv_flags);
-}
-
 #ifdef CONFIG_PCIEAER
 #include <linux/aer.h>
 
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ec784009a36b..440445ac7dfa 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2525,13 +2525,13 @@ int pci_scan_slot(struct pci_bus *bus, int devfn)
 	dev = pci_scan_single_device(bus, devfn);
 	if (!dev)
 		return 0;
-	if (!pci_dev_is_added(dev))
+	if (!dev->is_added)
 		nr++;
 
 	for (fn = next_fn(bus, dev, 0); fn > 0; fn = next_fn(bus, dev, fn)) {
 		dev = pci_scan_single_device(bus, devfn + fn);
 		if (dev) {
-			if (!pci_dev_is_added(dev))
+			if (!dev->is_added)
 				nr++;
 			dev->multifunction = 1;
 		}
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 461e7fd2756f..01ec7fcb5634 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -18,12 +18,11 @@ static void pci_stop_dev(struct pci_dev *dev)
 {
 	pci_pme_active(dev, false);
 
-	if (pci_dev_is_added(dev)) {
+	if (dev->is_added) {
 		device_release_driver(&dev->dev);
 		pci_proc_detach_device(dev);
 		pci_remove_sysfs_dev_files(dev);
-
-		pci_dev_assign_added(dev, false);
+		dev->is_added = 0;
 	}
 
 	if (dev->bus->self)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9b87f1936906..9799109c5e25 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -373,6 +373,7 @@ struct pci_dev {
 	unsigned int	transparent:1;		/* Subtractive decode bridge */
 	unsigned int	multifunction:1;	/* Multi-function device */
 
+	unsigned int	is_added:1;
 	unsigned int	is_busmaster:1;		/* Is busmaster */
 	unsigned int	no_msi:1;		/* May not use MSI */
 	unsigned int	no_64bit_msi:1; 	/* May only use 32-bit MSIs */
-- 
2.17.1