[PATCH 1/3] PCI: Method for removing PCI devices

Trent Piepho
2009-01-29T10:55:39Z

This patch adds an attribute named "remove" to a PCI device's sysfs
directory. Writing a non-zero value to this attribute will remove the PCI
device and any children of it.
---
Documentation/filesystems/sysfs-pci.txt | 9 +++++++++
drivers/pci/pci-sysfs.c | 26 ++++++++++++++++++++++++++
2 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 68ef488..54e014f 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -11,6 +11,7 @@ that support it. For example, a given bus might look like this:
| |-- device
| |-- irq
| |-- local_cpus
+ | |-- remove
| |-- resource
| |-- resource0
| |-- resource1
@@ -34,6 +35,7 @@ files, each with their own function.
device PCI device (ascii, ro)
irq IRQ number (ascii, ro)
local_cpus nearby CPU mask (cpumask, ro)
+ remove remove device from kernel's list (ascii, wo)
resource PCI resource host addresses (ascii, ro)
resource0..N PCI resource N, if present (binary, mmap)
resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap)
@@ -44,6 +46,7 @@ files, each with their own function.

ro - read only file
rw - file is readable and writable
+ wo - write only file
mmap - file is mmapable
ascii - file contains ascii text
binary - file contains binary data
@@ -62,6 +65,12 @@ ROM file, if available. It's disabled by default, however, so applications
should write the string "1" to the file to enable it before attempting a read
call, and disable it following the access by writing "0" to the file.

+The 'remove' file is used to remove the PCI device, by writing a non-zero
+integer to the file. This does not involve any kind of hot-plug functionality,
+e.g. powering off the device. The device is removed from the kernel's list of
+PCI devices, the sysfs directory for it removed, and the device will be removed
+from any drivers attached to it.
+
Accessing legacy resources through sysfs
----------------------------------------

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 3ddee7f..d422f37 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -219,6 +219,31 @@ msi_bus_store(struct device *dev, struct device_attribute *attr,
return count;
}

+static void remove_callback(void *data)
+{
+ pci_remove_bus_device((struct pci_dev *)data);
+}
+
+static ssize_t
+remove_store(struct device *dev, struct device_attribute *dummy,
+ const char *buf, size_t count)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ unsigned long val;
+
+ if (strict_strtoul(buf, 0, &val) < 0)
+ return -EINVAL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (val)
+ sysfs_schedule_callback(&dev->kobj, remove_callback, pdev,
+ THIS_MODULE);
+
+ return count;
+}
+
struct device_attribute pci_dev_attrs[] = {
__ATTR_RO(resource),
__ATTR_RO(vendor),
@@ -237,6 +262,7 @@ struct device_attribute pci_dev_attrs[] = {
__ATTR(broken_parity_status,(S_IRUGO|S_IWUSR),
broken_parity_status_show,broken_parity_status_store),
__ATTR(msi_bus, 0644, msi_bus_show, msi_bus_store),
+ __ATTR(remove, S_IWUSR, NULL, remove_store),
__ATTR_NULL,
};

--
1.5.4.3