This adds a pci_dev mutex which will be used to fix a number
of races related to the various state bits maintained in
that structure.
We call it "state_lock" with similarly named accessors to avoid
confusion with the pci_dev_lock() which uses the device_lock().
This is a low level mutex meant to protect the mapping between
the state fields and the hardware state, for example enabling
disabling, setting/clearing bus master etc...
These operations can happen while the device_lock() is already
held (but don't have to) so a separate mutex is preferable.
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/probe.c | 1 +
include/linux/pci.h | 17 +++++++++++++++++
2 files changed, 18 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 440445ac7dfa..3ce287ab6150 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2155,6 +2155,7 @@ struct pci_dev *pci_alloc_dev(struct pci_bus *bus)
INIT_LIST_HEAD(&dev->bus_list);
dev->dev.type = &pci_dev_type;
dev->bus = pci_bus_get(bus);
+ mutex_init(&dev->state_lock);
return dev;
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index f58bda204f09..0d4fc22df190 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -33,6 +33,7 @@
#include <linux/io.h>
#include <linux/resource_ext.h>
#include <uapi/linux/pci.h>
+#include <linux/mutex.h>
#include <linux/pci_ids.h>
@@ -443,8 +444,24 @@ struct pci_dev {
phys_addr_t rom; /* Physical address if not from BAR */
size_t romlen; /* Length if not from BAR */
char *driver_override; /* Driver name to force a match */
+
+ unsigned long priv_flags; /* Private flags for the PCI driver */
+
+ struct mutex state_lock; /* Protect local state bits */
+
+ /* --- Fields below this line are protected by the state_lock mutex */
};
+static inline void pci_dev_state_lock(struct pci_dev *dev)
+{
+ mutex_lock(&dev->state_lock);
+}
+
+static inline void pci_dev_state_unlock(struct pci_dev *dev)
+{
+ mutex_unlock(&dev->state_lock);
+}
+
static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
{
#ifdef CONFIG_PCI_IOV
--
2.17.1
