[RFC PATCH 05/10] PCI: Introduce /sys/bus/pci/rescan

Alex Chiang
2009-01-28T22:00:49Z

This interface allows the user to force a rescan of all PCI buses
in system, and rediscover devices that have been removed earlier.

Cc: Trent Piepho <xyzzy@speakeasy.org>
Cc: djwong@us.ibm.com
Reviewed-by: James Cameron <qz@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
---

Documentation/ABI/testing/sysfs-bus-pci | 9 +++++++++
drivers/pci/pci-sysfs.c | 28 ++++++++++++++++++++++++++++
2 files changed, 37 insertions(+), 0 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index faa21de..8c0abc7 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -1,3 +1,12 @@
+What: /sys/bus/pci/rescan
+Date: January 2009
+Contact: Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+ Writing a non-zero value to this attribute will
+ force a rescan of all PCI buses in the system, and
+ re-discover previously removed devices.
+ Depends on CONFIG_HOTPLUG.
+
What: /sys/bus/pci/devices/.../remove
Date: January 2009
Contact: Linux PCI developers <linux-pci@vger.kernel.org>
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 603a32d..c300242 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -986,12 +986,40 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
}
}

+#ifdef CONFIG_HOTPLUG
+static ssize_t bus_rescan_store(struct bus_type *bus, const char *buf, size_t count)
+{
+ unsigned long val;
+ struct pci_bus *b = NULL;
+
+ if (strict_strtoul(buf, 0, &val) < 0)
+ return -EINVAL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (val)
+ while ((b = pci_find_next_bus(b)) != NULL) {
+ pci_scan_child_bus(b);
+ pci_bus_add_devices(b);
+ }
+
+ return count;
+}
+static BUS_ATTR(rescan, S_IWUSR, NULL, bus_rescan_store);
+#endif
+
static int __init pci_sysfs_init(void)
{
struct pci_dev *pdev = NULL;
int retval;

sysfs_initialized = 1;
+#ifdef CONFIG_HOTPLUG
+ retval = bus_create_file(&pci_bus_type, &bus_attr_rescan);
+ if (retval)
+ return retval;
+#endif
for_each_pci_dev(pdev) {
retval = pci_create_sysfs_dev_files(pdev);
if (retval) {