diff mbox

[1/3] pci: add rescan to /sys/.../pci_bus/.../

Message ID 4DBF3AE3.8060109@kernel.org (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Yinghai Lu May 2, 2011, 11:14 p.m. UTC 
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.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 Documentation/ABI/testing/sysfs-bus-pci |    9 +++++++++
 drivers/pci/bus.c                       |    6 ++++++
 drivers/pci/pci-sysfs.c                 |   21 +++++++++++++++++++++
 drivers/pci/pci.h                       |    1 +
 drivers/pci/probe.c                     |    9 +++++++++
 5 files changed, 46 insertions(+)

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Comments

Jesse Barnes May 9, 2011, 8:52 p.m. UTC | #1 
On Mon, 02 May 2011 16:14:43 -0700
Yinghai Lu <yinghai@kernel.org> wrote:

> 
> 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.
> 
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>

I like the idea, and agree that bus rescanning makes sense.  Comments
below.

> ===================================================================
> --- linux-2.6.orig/drivers/pci/bus.c
> +++ linux-2.6/drivers/pci/bus.c
> @@ -163,6 +163,12 @@ int pci_bus_add_child(struct pci_bus *bu
>  
>  	bus->is_added = 1;
>  
> +#ifdef CONFIG_HOTPLUG
> +	retval = device_create_file(&bus->dev, &dev_attr_rescan);
> +	if (retval)
> +		return retval;
> +#endif
> +
>  	retval = device_create_file(&bus->dev, &dev_attr_cpuaffinity);
>  	if (retval)
>  		return retval;

Can you make this a separate function with a !CONFIG_HOTPLUG version so
we don't have an #ifdef inside this function?

> Index: linux-2.6/drivers/pci/pci.h
> ===================================================================
> --- linux-2.6.orig/drivers/pci/pci.h
> +++ linux-2.6/drivers/pci/pci.h
> @@ -159,6 +159,7 @@ extern struct device_attribute pci_dev_a
>  extern struct device_attribute dev_attr_cpuaffinity;
>  extern struct device_attribute dev_attr_cpulistaffinity;
>  #ifdef CONFIG_HOTPLUG
> +extern struct device_attribute dev_attr_rescan;
>  extern struct bus_attribute pci_bus_attrs[];
>  #else
>  #define pci_bus_attrs	NULL
> Index: linux-2.6/drivers/pci/probe.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/probe.c
> +++ linux-2.6/drivers/pci/probe.c
> @@ -1471,6 +1471,11 @@ struct pci_bus * pci_create_bus(struct d
>  	error = device_create_file(&b->dev, &dev_attr_cpuaffinity);
>  	if (error)
>  		goto dev_create_file_err;
> +#ifdef CONFIG_HOTPLUG
> +	error = device_create_file(&b->dev, &dev_attr_rescan);
> +	if (error)
> +		goto dev_create_bus_rescan_err;
> +#endif

Same here.

>  
>  	/* Create legacy_io and legacy_mem files for this bus */
>  	pci_create_legacy_files(b);
> @@ -1481,6 +1486,10 @@ struct pci_bus * pci_create_bus(struct d
>  
>  	return b;
>  
> +#ifdef CONFIG_HOTPLUG
> +dev_create_bus_rescan_err:
> +	device_remove_file(&b->dev, &dev_attr_cpuaffinity);
> +#endif

Without the ifdef above, this could be unconditional; it just won't be
hit in the !CONFIG_HOTPLUG case.

Thanks,
diff mbox

Patch

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 +318,27 @@  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;
+}
+
+DEVICE_ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, dev_bus_rescan_store);
+
 #endif
 
 struct device_attribute pci_dev_attrs[] = {
Index: linux-2.6/drivers/pci/bus.c
===================================================================
--- linux-2.6.orig/drivers/pci/bus.c
+++ linux-2.6/drivers/pci/bus.c
@@ -163,6 +163,12 @@  int pci_bus_add_child(struct pci_bus *bu
 
 	bus->is_added = 1;
 
+#ifdef CONFIG_HOTPLUG
+	retval = device_create_file(&bus->dev, &dev_attr_rescan);
+	if (retval)
+		return retval;
+#endif
+
 	retval = device_create_file(&bus->dev, &dev_attr_cpuaffinity);
 	if (retval)
 		return retval;
Index: linux-2.6/drivers/pci/pci.h
===================================================================
--- linux-2.6.orig/drivers/pci/pci.h
+++ linux-2.6/drivers/pci/pci.h
@@ -159,6 +159,7 @@  extern struct device_attribute pci_dev_a
 extern struct device_attribute dev_attr_cpuaffinity;
 extern struct device_attribute dev_attr_cpulistaffinity;
 #ifdef CONFIG_HOTPLUG
+extern struct device_attribute dev_attr_rescan;
 extern struct bus_attribute pci_bus_attrs[];
 #else
 #define pci_bus_attrs	NULL
Index: linux-2.6/drivers/pci/probe.c
===================================================================
--- linux-2.6.orig/drivers/pci/probe.c
+++ linux-2.6/drivers/pci/probe.c
@@ -1471,6 +1471,11 @@  struct pci_bus * pci_create_bus(struct d
 	error = device_create_file(&b->dev, &dev_attr_cpuaffinity);
 	if (error)
 		goto dev_create_file_err;
+#ifdef CONFIG_HOTPLUG
+	error = device_create_file(&b->dev, &dev_attr_rescan);
+	if (error)
+		goto dev_create_bus_rescan_err;
+#endif
 
 	/* Create legacy_io and legacy_mem files for this bus */
 	pci_create_legacy_files(b);
@@ -1481,6 +1486,10 @@  struct pci_bus * pci_create_bus(struct d
 
 	return b;
 
+#ifdef CONFIG_HOTPLUG
+dev_create_bus_rescan_err:
+	device_remove_file(&b->dev, &dev_attr_cpuaffinity);
+#endif
 dev_create_file_err:
 	device_unregister(&b->dev);
 class_dev_reg_err:
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@vger.kernel.org>
+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@vger.kernel.org>