summaryrefslogtreecommitdiffstats
path: root/drivers
diff options
context:
space:
mode:
authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-01-04 14:23:56 -0500
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-01-12 12:00:07 -0500
commita96d627abaac899e8bfaf18fd0578b228c9c752f (patch)
tree0ea927e4a1acb8f5a11c29642b960309c732c3a9 /drivers
parent8605c6844fb9bdf55471bb87c3ac62d44eb34e04 (diff)
pci: Introduce __pci_reset_function_locked to be used when holding device_lock.
The use case of this is when a driver wants to call FLR when a device is attached to it using the SysFS "bind" or "unbind" functionality. The call chain when a user does "bind" looks as so: echo "0000:01.07.0" > /sys/bus/pci/drivers/XXXX/bind and ends up calling: driver_bind: device_lock(dev); <=== TAKES LOCK XXXX_probe: .. pci_enable_device() ...__pci_reset_function(), which calls pci_dev_reset(dev, 0): if (!0) { device_lock(dev) <==== DEADLOCK The __pci_reset_function_locked function allows the the drivers 'probe' function to call the "pci_reset_function" while still holding the driver mutex lock. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/pci.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 97fff785e97..192be5dbde5 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3163,6 +3163,31 @@ int __pci_reset_function(struct pci_dev *dev)
EXPORT_SYMBOL_GPL(__pci_reset_function);
/**
+ * __pci_reset_function_locked - reset a PCI device function while holding
+ * the @dev mutex lock.
+ * @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.
+ *
+ * The device function is presumed to be unused and the caller is holding
+ * the device mutex lock when this function is called.
+ * Resetting the device will make the contents of PCI configuration space
+ * random, so any caller of this must be prepared to reinitialise the
+ * device including MSI, bus mastering, BARs, decoding IO and memory spaces,
+ * etc.
+ *
+ * Returns 0 if the device function was successfully reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int __pci_reset_function_locked(struct pci_dev *dev)
+{
+ return pci_dev_reset(dev, 1);
+}
+EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
+
+/**
* pci_probe_reset_function - check whether the device can be safely reset
* @dev: PCI device to reset
*