[PATCH V4 4/7] PCI: Unify try slot and bus reset API

Sinan Kaya
2018-06-28T19:31:02Z

Drivers are expected to call pci_try_reset_slot() or pci_try_reset_bus() by
querying if a system supports hotplug or not. A survey showed that most
drivers don't do this and we are leaking hotplug capability to the user.

Hide pci_try_slot_reset() from drivers and embed into pci_try_bus_reset().
Change pci_try_reset_bus() parameter from struct pci_bus to struct pci_dev.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
drivers/infiniband/hw/hfi1/pcie.c | 2 +-
drivers/pci/pci.c | 26 +++++++++++++++++++++-----
drivers/vfio/pci/vfio_pci.c | 6 ++----
include/linux/pci.h | 3 +--
4 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/pcie.c b/drivers/infiniband/hw/hfi1/pcie.c
index 4570c4d..df4f2d3 100644
--- a/drivers/infiniband/hw/hfi1/pcie.c
+++ b/drivers/infiniband/hw/hfi1/pcie.c
@@ -905,7 +905,7 @@ static int trigger_sbr(struct hfi1_devdata *dd)
* delay after a reset is required. Per spec requirements,
* the link is either working or not after that point.
*/
- return pci_try_reset_bus(dev->bus);
+ return pci_try_reset_bus(dev);
}

/*
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 236220c..79a1566 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4817,12 +4817,12 @@ int pci_reset_slot(struct pci_slot *slot)
EXPORT_SYMBOL_GPL(pci_reset_slot);

/**
- * pci_try_reset_slot - Try to reset a PCI slot
+ * __pci_try_reset_slot - Try to reset a PCI slot
* @slot: PCI slot to reset
*
* Same as above except return -EAGAIN if the slot cannot be locked
*/
-int pci_try_reset_slot(struct pci_slot *slot)
+static int __pci_try_reset_slot(struct pci_slot *slot)
{
int rc;

@@ -4843,7 +4843,6 @@ int pci_try_reset_slot(struct pci_slot *slot)

return rc;
}
-EXPORT_SYMBOL_GPL(pci_try_reset_slot);

static int pci_bus_reset(struct pci_bus *bus, int probe)
{
@@ -4906,12 +4905,12 @@ int pci_reset_bus(struct pci_bus *bus)
EXPORT_SYMBOL_GPL(pci_reset_bus);

/**
- * pci_try_reset_bus - Try to reset a PCI bus
+ * __pci_try_reset_bus - Try to reset a PCI bus
* @bus: top level PCI bus to reset
*
* Same as above except return -EAGAIN if the bus cannot be locked
*/
-int pci_try_reset_bus(struct pci_bus *bus)
+static int __pci_try_reset_bus(struct pci_bus *bus)
{
int rc;

@@ -4932,6 +4931,23 @@ int pci_try_reset_bus(struct pci_bus *bus)

return rc;
}
+
+/**
+ * pci_try_reset_bus - Try to reset a PCI bus
+ * @pdev: top level PCI device to reset via slot/bus
+ *
+ * Same as above except return -EAGAIN if the bus cannot be locked
+ */
+int pci_try_reset_bus(struct pci_dev *pdev)
+{
+ bool slot = false;
+
+ if (!pci_probe_reset_slot(pdev->slot))
+ slot = true;
+
+ return slot ? __pci_try_reset_slot(pdev->slot) :
+ __pci_try_reset_bus(pdev->bus);
+}
EXPORT_SYMBOL_GPL(pci_try_reset_bus);

/**
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index b423a30..71018ec 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1010,8 +1010,7 @@ static long vfio_pci_ioctl(void *device_data,
&info, slot);
if (!ret)
/* User has access, do the reset */
- ret = slot ? pci_try_reset_slot(vdev->pdev->slot) :
- pci_try_reset_bus(vdev->pdev->bus);
+ ret = pci_try_reset_bus(vdev->pdev);

hot_reset_release:
for (i--; i >= 0; i--)
@@ -1373,8 +1372,7 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
}

if (needs_reset)
- ret = slot ? pci_try_reset_slot(vdev->pdev->slot) :
- pci_try_reset_bus(vdev->pdev->bus);
+ ret = pci_try_reset_bus(vdev->pdev);

put_devs:
for (i = 0; i < devs.cur_index; i++) {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 6b12ce2..f5c85b6 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1096,10 +1096,9 @@ int pci_reset_function_locked(struct pci_dev *dev);
int pci_try_reset_function(struct pci_dev *dev);
int pci_probe_reset_slot(struct pci_slot *slot);
int pci_reset_slot(struct pci_slot *slot);
-int pci_try_reset_slot(struct pci_slot *slot);
int pci_probe_reset_bus(struct pci_bus *bus);
int pci_reset_bus(struct pci_bus *bus);
-int pci_try_reset_bus(struct pci_bus *bus);
+int pci_try_reset_bus(struct pci_dev *dev);
void pci_reset_secondary_bus(struct pci_dev *dev);
void pcibios_reset_secondary_bus(struct pci_dev *dev);
void pci_update_resource(struct pci_dev *dev, int resno);
--
2.7.4