Re: New commands to configure IOV features

[Yinghai Lu <yinghai@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 911 bytes --]

On Wed, Sep 19, 2012 at 3:46 PM, Ben Hutchings
<bhutchings@solarflare.com> wrote:
> On Wed, 2012-09-19 at 15:17 -0700, Yinghai Lu wrote:
>> +max_vfs_store(struct device *dev, struct device_attribute *attr,
>> +                const char *buf, size_t count)
>> +{
>> +       unsigned long val;
>> +       struct pci_dev *pdev = to_pci_dev(dev);
>> +
>> +       if (strict_strtoul(buf, 0, &val) < 0)
>> +               return -EINVAL;
>> +
>> +       pdev->max_vfs = val;
>> +
>> +       return count;
>> +}
> [...]
>
> Then what would actually trigger creation of the VFs?  There's no way we
> can assume that some sysfs attribute will be written before the PF
> driver is loaded (what if it's built-in?).  I thought the idea was to
> add a driver callback that would be called when the sysfs attribute was
> written.

could just stop the device and add it back again?

just like updated patch.

Thanks

Yinghai

[-- Attachment #2: sriov_xxx.patch --]
[-- Type: application/octet-stream, Size: 3664 bytes --]

Subject: [PATCH] PCI: Add max_vfs in sysfs per pci device where supports

driver later need to check dev->max_vfs in /sys

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

---
 drivers/pci/pci-sysfs.c |   57 ++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/pci/remove.c    |    2 -
 include/linux/pci.h     |    2 +
 3 files changed, 60 insertions(+), 1 deletion(-)

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
@@ -459,6 +459,58 @@ boot_vga_show(struct device *dev, struct
 }
 struct device_attribute vga_attr = __ATTR_RO(boot_vga);
 
+static ssize_t
+max_vfs_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	return sprintf(buf, "%u\n", pdev->max_vfs);
+}
+
+static void rebind_callback(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	int err;
+
+	mutex_lock(&pci_remove_rescan_mutex);
+	pci_stop_bus_device(pdev);
+	err = pci_bus_add_device(pdev);
+	if (!err) {
+		struct pci_bus *child = pdev->subordinate;
+
+		if (child) {
+			pci_bus_add_devices(child);
+			if (!child->is_added)
+				pci_bus_add_child(child);
+		}
+	}
+	mutex_unlock(&pci_remove_rescan_mutex);
+}
+static ssize_t
+max_vfs_store(struct device *dev, struct device_attribute *attr,
+		 const char *buf, size_t count)
+{
+	unsigned long val;
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	if (strict_strtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	pdev->max_vfs = val;
+
+	if (pdev->is_added) {
+		int err;
+		err = device_schedule_callback(dev, rebind_callback);
+
+		if (err)
+			return err;
+	}
+
+	return count;
+}
+struct device_attribute max_vfs_attr =
+	__ATTR(max_vfs, 0644, max_vfs_show, max_vfs_store);
+
 static void
 pci_config_pm_runtime_get(struct pci_dev *pdev)
 {
@@ -1406,6 +1458,7 @@ late_initcall(pci_sysfs_init);
 
 static struct attribute *pci_dev_dev_attrs[] = {
 	&vga_attr.attr,
+	&max_vfs_attr.attr,
 	NULL,
 };
 
@@ -1419,6 +1472,10 @@ static umode_t pci_dev_attrs_are_visible
 		if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
 			return 0;
 
+	if (a == &max_vfs_attr.attr)
+		if (!pdev->is_physfn)
+			return 0;
+
 	return a->mode;
 }
 
Index: linux-2.6/include/linux/pci.h
===================================================================
--- linux-2.6.orig/include/linux/pci.h
+++ linux-2.6/include/linux/pci.h
@@ -359,6 +359,7 @@ struct pci_dev {
 	unsigned int	broken_intx_masking:1;
 	unsigned int	io_window_1k:1;	/* Intel P2P bridge 1K I/O windows */
 	pci_dev_flags_t dev_flags;
+	unsigned int	max_vfs;
 	atomic_t	enable_cnt;	/* pci_enable_device has been called */
 
 	u32		saved_config_space[16]; /* config space saved at suspend time */
@@ -812,6 +813,7 @@ u8 pci_common_swizzle(struct pci_dev *de
 extern struct pci_dev *pci_dev_get(struct pci_dev *dev);
 extern void pci_dev_put(struct pci_dev *dev);
 extern void pci_remove_bus(struct pci_bus *b);
+void pci_stop_bus_device(struct pci_dev *dev);
 extern void pci_stop_and_remove_bus_device(struct pci_dev *dev);
 void pci_stop_root_bus(struct pci_bus *bus);
 void pci_remove_root_bus(struct pci_bus *bus);
Index: linux-2.6/drivers/pci/remove.c
===================================================================
--- linux-2.6.orig/drivers/pci/remove.c
+++ linux-2.6/drivers/pci/remove.c
@@ -55,7 +55,7 @@ void pci_remove_bus(struct pci_bus *bus)
 }
 EXPORT_SYMBOL(pci_remove_bus);
 
-static void pci_stop_bus_device(struct pci_dev *dev)
+void pci_stop_bus_device(struct pci_dev *dev)
 {
 	struct pci_bus *bus = dev->subordinate;
 	struct pci_dev *child, *tmp;