From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
This change makes it so that there are several new calls available.
The first is __pci_reset_dev which works similar to pci_reset_dev, however
it does not obtain the device lock. This is important as I found several
cases such as __pci_reset_function in which the call was obtaining the
device lock even though the lock had yet to be initialized. In addition if
one wishes to do such a reset during probe it will hang since the device
lock is already being held.
The second change that was added was a function named
pci_reset_device_function. This function is similar to pci_reset_function
however it does not hold the device lock and so it as well can be called
during the driver probe routine.
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
---
drivers/pci/pci.c | 74 +++++++++++++++++++++++++++++++++++++++++++--------
include/linux/pci.h | 1 +
2 files changed, 64 insertions(+), 11 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 60f30e7..1421bc7 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2445,17 +2445,14 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
return 0;
}
-static int pci_dev_reset(struct pci_dev *dev, int probe)
+static int __pci_dev_reset(struct pci_dev *dev, int probe)
{
int rc;
might_sleep();
- if (!probe) {
+ if (!probe)
pci_block_user_cfg_access(dev);
- /* block PM suspend, driver probe, etc. */
- device_lock(&dev->dev);
- }
rc = pci_dev_specific_reset(dev, probe);
if (rc != -ENOTTY)
@@ -2474,11 +2471,26 @@ static int pci_dev_reset(struct pci_dev *dev, int probe)
goto done;
rc = pci_parent_bus_reset(dev, probe);
+
done:
- if (!probe) {
- device_unlock(&dev->dev);
+ if (!probe)
pci_unblock_user_cfg_access(dev);
- }
+
+ return rc;
+}
+
+static int pci_dev_reset(struct pci_dev *dev, int probe)
+{
+ int rc;
+
+ /* block PM suspend, driver probe, etc. */
+ if (!probe)
+ device_lock(&dev->dev);
+
+ rc = __pci_dev_reset(dev, probe);
+
+ if (!probe)
+ device_unlock(&dev->dev);
return rc;
}
@@ -2502,7 +2514,7 @@ done:
*/
int __pci_reset_function(struct pci_dev *dev)
{
- return pci_dev_reset(dev, 0);
+ return __pci_dev_reset(dev, 0);
}
EXPORT_SYMBOL_GPL(__pci_reset_function);
@@ -2519,7 +2531,7 @@ EXPORT_SYMBOL_GPL(__pci_reset_function);
*/
int pci_probe_reset_function(struct pci_dev *dev)
{
- return pci_dev_reset(dev, 1);
+ return __pci_dev_reset(dev, 1);
}
/**
@@ -2542,7 +2554,7 @@ int pci_reset_function(struct pci_dev *dev)
{
int rc;
- rc = pci_dev_reset(dev, 1);
+ rc = __pci_dev_reset(dev, 1);
if (rc)
return rc;
@@ -2563,6 +2575,46 @@ int pci_reset_function(struct pci_dev *dev)
EXPORT_SYMBOL_GPL(pci_reset_function);
/**
+ * pci_reset_device_function - quiesce and reinitialize a PCI device function
+ * @dev: PCI device to reset
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device. The PCI device must be responsive
+ * to PCI config space in order to use this function.
+ *
+ * This function is very similar to pci_reset_function, however this function
+ * does not obtain the device lock during the reset. This is due to the fact
+ * that the call is meant to be used during probe if the reset_devices
+ * kernel parameter is set.
+ *
+ * Returns 0 if the device function was successfully reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int pci_reset_device_function(struct pci_dev *dev)
+{
+ int rc;
+
+ rc = __pci_dev_reset(dev, 1);
+ if (rc)
+ return rc;
+
+ pci_save_state(dev);
+
+ /*
+ * both INTx and MSI are disabled after the Interrupt Disable bit
+ * is set and the Bus Master bit is cleared.
+ */
+ pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
+
+ rc = __pci_dev_reset(dev, 0);
+
+ pci_restore_state(dev);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(pci_reset_device_function);
+
+/**
* pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count
* @dev: PCI device to query
*
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 6a471ab..c7708d3 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -789,6 +789,7 @@ int pcie_get_readrq(struct pci_dev *dev);
int pcie_set_readrq(struct pci_dev *dev, int rq);
int __pci_reset_function(struct pci_dev *dev);
int pci_reset_function(struct pci_dev *dev);
+int pci_reset_device_function(struct pci_dev *dev);
void pci_update_resource(struct pci_dev *dev, int resno);
int __must_check pci_assign_resource(struct pci_dev *dev, int i);
int pci_select_bars(struct pci_dev *dev, unsigned long flags);
--
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