[RFC PATCH 1/6] Revert "PCI: Fix is_added/is_busmaster race condition"

From: Benjamin Herrenschmidt
Date: Fri Aug 17 2018 - 00:50:10 EST


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@xxxxxxxxxxxxxxxxxxx>
---
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