On 05/09/2011 03:44 PM, Greg KH wrote:
> On Mon, May 09, 2011 at 03:34:25PM -0700, Yinghai Lu wrote:
>> [PATCH -v2 1/3] pci: add rescan to /sys/.../pci_bus/.../
>>
...
>> +DEVICE_ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, dev_bus_rescan_store);
>> +
>> +int pci_bus_create_rescan_file(struct pci_bus *bus)
>> +{
>> + return device_create_file(&bus->dev, &dev_attr_rescan);
>> +}
>> +
>> +void pci_bus_remove_rescan_file(struct pci_bus *bus)
>> +{
>> + device_remove_file(&bus->dev, &dev_attr_rescan);
>> +}
>
> No, please make it part of the attribute for this device type, otherwise
> you will race with userspace trying to create the file after it has been
> announced that the device is present.
>
Thanks please check.
[PATCH -v3 1/3] pci: add rescan to /sys/.../pci_bus/.../
After remove the device from /sys, we have to rescan all or
find out the bridge and access /sys../device/rescan there.
this patch add /sys/.../pci_bus/.../rescan. So user can rescan more easy.
that is more clean and easy to understand.
like after remove 0000:c4:00.0, you can rescan 0000:c4 directly.
-v2: According to Jesse, use function instead of exposing attr, so could hide
#ifdef in header file.
also add code to remove rescan file in remove path.
-v3: GregKH pointed out that we should use dev_attrs to avoid racing.
So add pcibus_attrs and make it to be member of pcibus_attrs.
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-pci | 9 +++++++++
drivers/pci/pci-sysfs.c | 26 ++++++++++++++++++++++++++
drivers/pci/pci.h | 2 ++
drivers/pci/probe.c | 1 +
4 files changed, 38 insertions(+)
Index: linux-2.6/Documentation/ABI/testing/sysfs-bus-pci
===================================================================
--- linux-2.6.orig/Documentation/ABI/testing/sysfs-bus-pci
+++ linux-2.6/Documentation/ABI/testing/sysfs-bus-pci
@@ -74,6 +74,15 @@ Description:
hot-remove the PCI device and any of its children.
Depends on CONFIG_HOTPLUG.
+What: /sys/bus/pci/devices/.../pci_bus/.../rescan
+Date: May 2011
+Contact: Linux PCI developers <linux-pci@xxxxxxxxxxxxxxx>
+Description:
+ Writing a non-zero value to this attribute will
+ force a rescan of the bus and all child buses,
+ and re-discover devices removed earlier from this
+ part of the device tree. Depends on CONFIG_HOTPLUG.
+
What: /sys/bus/pci/devices/.../rescan
Date: January 2009
Contact: Linux PCI developers <linux-pci@xxxxxxxxxxxxxxx>
Index: linux-2.6/drivers/pci/pci-sysfs.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci-sysfs.c
+++ linux-2.6/drivers/pci/pci-sysfs.c
@@ -318,6 +318,25 @@ remove_store(struct device *dev, struct
count = ret;
return count;
}
+
+static ssize_t
+dev_bus_rescan_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ struct pci_bus *bus = to_pci_bus(dev);
+
+ if (strict_strtoul(buf, 0, &val) < 0)
+ return -EINVAL;
+
+ if (val) {
+ mutex_lock(&pci_remove_rescan_mutex);
+ pci_rescan_bus(bus);
+ mutex_unlock(&pci_remove_rescan_mutex);
+ }
+ return count;
+}
+
#endif
struct device_attribute pci_dev_attrs[] = {
@@ -346,6 +365,13 @@ struct device_attribute pci_dev_attrs[]
#endif
__ATTR_NULL,
};
+
+struct device_attribute pcibus_attrs[] = {
+#ifdef CONFIG_HOTPLUG
+ __ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, dev_bus_rescan_store),
+#endif
+ __ATTR_NULL,
+};
static ssize_t
boot_vga_show(struct device *dev, struct device_attribute *attr, char *buf)
Index: linux-2.6/drivers/pci/pci.h
===================================================================
--- linux-2.6.orig/drivers/pci/pci.h
+++ linux-2.6/drivers/pci/pci.h
@@ -160,8 +160,10 @@ extern struct device_attribute dev_attr_
extern struct device_attribute dev_attr_cpulistaffinity;
#ifdef CONFIG_HOTPLUG
extern struct bus_attribute pci_bus_attrs[];
+extern struct device_attribute pcibus_attrs[];
#else
#define pci_bus_attrs NULL
+#define pcibus_attrs NULL
#endif
Index: linux-2.6/drivers/pci/probe.c
===================================================================
--- linux-2.6.orig/drivers/pci/probe.c
+++ linux-2.6/drivers/pci/probe.c
@@ -95,6 +95,7 @@ static void release_pcibus_dev(struct de
static struct class pcibus_class = {
.name = "pci_bus",
.dev_release = &release_pcibus_dev,
+ .dev_attrs = pcibus_attrs,
};
static int __init pcibus_class_init(void)
--
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