[REBASED PATCH 1/2] usbip: usbip_host: delete device from busid_table after rebind

[REBASED PATCH 1/2] usbip: usbip_host: delete device from busid_table after rebind

[Shuah Khan (Samsung OSG)]

Device is left in the busid_table after unbind and rebind. Rebind
initiates usb bus scan and the original driver claims the device.
After rescan the device should be deleted from the busid_table as
it no longer belongs to usbip_host.

Fix it to delete the device after device_attach() succeeds.

Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
---
 drivers/usb/usbip/stub_main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c
index d41d0cdeec0f..fb46bd62d538 100644
--- a/drivers/usb/usbip/stub_main.c
+++ b/drivers/usb/usbip/stub_main.c
@@ -186,6 +186,9 @@ static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 	if (!bid)
 		return -ENODEV;
 
+	/* mark the device for deletion so probe ignores it during rescan */
+	bid->status = STUB_BUSID_OTHER;
+
 	/* device_attach() callers should hold parent lock for USB */
 	if (bid->udev->dev.parent)
 		device_lock(bid->udev->dev.parent);
@@ -197,6 +200,9 @@ static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 		return ret;
 	}
 
+	/* delete device from busid_table */
+	del_match_busid((char *) buf);
+
 	return count;
 }
 
-- 
2.14.1

[REBASED PATCH 2/2] usbip: usbip_host: run rebind from exit when module is removed

[Shuah Khan (Samsung OSG)]

After removing usbip_host module, devices it releases are left without
a driver. For example, when a keyboard or a mass storage device are
bound to usbip_host when it is removed, these devices are no longer
bound to any driver.

Fix it to run device_attach() from the module exit routine to restore
the devices to their original drivers. This includes cleanup changes
and moving device_attach() code to a common routine to be called from
rebind_store() and usbip_host_exit().

Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
---
 drivers/usb/usbip/stub_dev.c  |  6 +----
 drivers/usb/usbip/stub_main.c | 60 ++++++++++++++++++++++++++++++++++++-------
 2 files changed, 52 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/usbip/stub_dev.c b/drivers/usb/usbip/stub_dev.c
index 7813c1862941..9d0425113c4b 100644
--- a/drivers/usb/usbip/stub_dev.c
+++ b/drivers/usb/usbip/stub_dev.c
@@ -448,12 +448,8 @@ static void stub_disconnect(struct usb_device *udev)
 	busid_priv->sdev = NULL;
 	stub_device_free(sdev);
 
-	if (busid_priv->status == STUB_BUSID_ALLOC) {
+	if (busid_priv->status == STUB_BUSID_ALLOC)
 		busid_priv->status = STUB_BUSID_ADDED;
-	} else {
-		busid_priv->status = STUB_BUSID_OTHER;
-		del_match_busid((char *)udev_busid);
-	}
 }
 
 #ifdef CONFIG_PM
diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c
index fb46bd62d538..587b9bc10042 100644
--- a/drivers/usb/usbip/stub_main.c
+++ b/drivers/usb/usbip/stub_main.c
@@ -14,6 +14,7 @@
 #define DRIVER_DESC "USB/IP Host Driver"
 
 struct kmem_cache *stub_priv_cache;
+
 /*
  * busid_tables defines matching busids that usbip can grab. A user can change
  * dynamically what device is locally used and what device is exported to a
@@ -169,6 +170,51 @@ static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
 }
 static DRIVER_ATTR_RW(match_busid);
 
+static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
+{
+	int ret;
+
+	/* device_attach() callers should hold parent lock for USB */
+	if (busid_priv->udev->dev.parent)
+		device_lock(busid_priv->udev->dev.parent);
+	ret = device_attach(&busid_priv->udev->dev);
+	if (busid_priv->udev->dev.parent)
+		device_unlock(busid_priv->udev->dev.parent);
+	if (ret < 0) {
+		dev_err(&busid_priv->udev->dev, "rebind failed\n");
+		return ret;
+	}
+	return 0;
+}
+
+static void stub_device_rebind(void)
+{
+#if IS_MODULE(CONFIG_USBIP_HOST)
+	struct bus_id_priv *busid_priv;
+	int i;
+
+	/* update status to STUB_BUSID_OTHER so probe ignores the device */
+	spin_lock(&busid_table_lock);
+	for (i = 0; i < MAX_BUSID; i++) {
+		if (busid_table[i].name[0] &&
+		    busid_table[i].shutdown_busid) {
+			busid_priv = &(busid_table[i]);
+			busid_priv->status = STUB_BUSID_OTHER;
+		}
+	}
+	spin_unlock(&busid_table_lock);
+
+	/* now run rebind */
+	for (i = 0; i < MAX_BUSID; i++) {
+		if (busid_table[i].name[0] &&
+		    busid_table[i].shutdown_busid) {
+			busid_priv = &(busid_table[i]);
+			do_rebind(busid_table[i].name, busid_priv);
+		}
+	}
+#endif
+}
+
 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 				 size_t count)
 {
@@ -189,16 +235,9 @@ static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 	/* mark the device for deletion so probe ignores it during rescan */
 	bid->status = STUB_BUSID_OTHER;
 
-	/* device_attach() callers should hold parent lock for USB */
-	if (bid->udev->dev.parent)
-		device_lock(bid->udev->dev.parent);
-	ret = device_attach(&bid->udev->dev);
-	if (bid->udev->dev.parent)
-		device_unlock(bid->udev->dev.parent);
-	if (ret < 0) {
-		dev_err(&bid->udev->dev, "rebind failed\n");
+	ret = do_rebind((char *) buf, bid);
+	if (ret < 0)
 		return ret;
-	}
 
 	/* delete device from busid_table */
 	del_match_busid((char *) buf);
@@ -323,6 +362,9 @@ static void __exit usbip_host_exit(void)
 	 */
 	usb_deregister_device_driver(&stub_driver);
 
+	/* initiate scan to attach devices */
+	stub_device_rebind();
+
 	kmem_cache_destroy(stub_priv_cache);
 }
 
-- 
2.14.1

Re: [REBASED PATCH 1/2] usbip: usbip_host: delete device from busid_table after rebind

[Greg KH]

On Mon, Apr 30, 2018 at 04:17:19PM -0600, Shuah Khan (Samsung OSG) wrote:
> Device is left in the busid_table after unbind and rebind. Rebind
> initiates usb bus scan and the original driver claims the device.
> After rescan the device should be deleted from the busid_table as
> it no longer belongs to usbip_host.
> 
> Fix it to delete the device after device_attach() succeeds.
> 
> Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
> ---
>  drivers/usb/usbip/stub_main.c | 6 ++++++
>  1 file changed, 6 insertions(+)

Why are these REBASED?  I can't remember the first version of these
patches, what are these for?

confused,

greg k-h

Re: [REBASED PATCH 1/2] usbip: usbip_host: delete device from busid_table after rebind

[Shuah Khan]

On 04/30/2018 04:48 PM, Greg KH wrote:
> On Mon, Apr 30, 2018 at 04:17:19PM -0600, Shuah Khan (Samsung OSG) wrote:
>> Device is left in the busid_table after unbind and rebind. Rebind
>> initiates usb bus scan and the original driver claims the device.
>> After rescan the device should be deleted from the busid_table as
>> it no longer belongs to usbip_host.
>>
>> Fix it to delete the device after device_attach() succeeds.
>>
>> Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
>> ---
>>  drivers/usb/usbip/stub_main.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
> 
> Why are these REBASED?  I can't remember the first version of these
> patches, what are these for?
> 
> confused,
> 
> greg k-h
> 
> 

Here is the original patches

https://patchwork.kernel.org/patch/10337657/
https://patchwork.kernel.org/patch/10337661/

I sent a 3 patch series and the last two didn't apply to usb-next. You asked me to
rebase them. I realized the reason they didn't apply is because these two depend on
the fixes that went into 4.17-rc3 and now with usb-next at 4.17-rc3, they apply.

I ended up generating patches on usb-next latest and resend the rebased patches.

Hope this makes sense.

thanks,
-- Shuah