[PATCH v2 0/2] USB: Simplify running code on shutdown for USB devices

[PATCH v2 0/2] USB: Simplify running code on shutdown for USB devices

[Aditya Garg]

Currently there is no standardized method for USB drivers to handle
shutdown events.

The first patch in this series fixes this by simplifying running code
on shutdown for USB devices by adding a shutdown callback to usb_driver.

The second patch implements this new callback to the UAS driver.

Kerem Karabay (2):
  USB: core: add 'shutdown' callback to usb_driver
  scsi: usb: uas: Implement the new shutdown callback

 drivers/usb/core/driver.c | 14 ++++++++++++++
 drivers/usb/storage/uas.c |  5 ++---
 include/linux/usb.h       |  3 +++
 3 files changed, 19 insertions(+), 3 deletions(-)

-- 
2.43.0

[PATCH v2 1/2] USB: core: add 'shutdown' callback to usb_driver

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

Currently there is no standardized method for USB drivers to handle
shutdown events. This patch simplifies running code on shutdown for USB
devices by adding a shutdown callback to usb_driver.

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
 drivers/usb/core/driver.c | 14 ++++++++++++++
 include/linux/usb.h       |  3 +++
 2 files changed, 17 insertions(+)

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index e02ba15f6..b35734d03 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -517,6 +517,19 @@ static int usb_unbind_interface(struct device *dev)
 	return 0;
 }
 
+static void usb_shutdown_interface(struct device *dev)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_driver *driver;
+
+	if (!dev->driver)
+		return;
+
+	driver = to_usb_driver(dev->driver);
+	if (driver->shutdown)
+		driver->shutdown(intf);
+}
+
 /**
  * usb_driver_claim_interface - bind a driver to an interface
  * @driver: the driver to be bound
@@ -1059,6 +1072,7 @@ int usb_register_driver(struct usb_driver *new_driver, struct module *owner,
 	new_driver->driver.bus = &usb_bus_type;
 	new_driver->driver.probe = usb_probe_interface;
 	new_driver->driver.remove = usb_unbind_interface;
+	new_driver->driver.shutdown = usb_shutdown_interface;
 	new_driver->driver.owner = owner;
 	new_driver->driver.mod_name = mod_name;
 	new_driver->driver.dev_groups = new_driver->dev_groups;
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 1913a1383..832997a9d 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1171,6 +1171,7 @@ extern ssize_t usb_show_dynids(struct usb_dynids *dynids, char *buf);
  *	post_reset method is called.
  * @post_reset: Called by usb_reset_device() after the device
  *	has been reset
+ * @shutdown: Called at shut-down time to quiesce the device.
  * @id_table: USB drivers use ID table to support hotplugging.
  *	Export this with MODULE_DEVICE_TABLE(usb,...).  This must be set
  *	or your driver's probe function will never get called.
@@ -1222,6 +1223,8 @@ struct usb_driver {
 	int (*pre_reset)(struct usb_interface *intf);
 	int (*post_reset)(struct usb_interface *intf);
 
+	void (*shutdown)(struct usb_interface *intf);
+
 	const struct usb_device_id *id_table;
 	const struct attribute_group **dev_groups;
 
-- 
2.43.0

[PATCH v2 2/2] scsi: usb: uas: Implement the new shutdown callback

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

This patch implements the new shutdown callback method added to
usb_driver on the UAS driver.

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
 drivers/usb/storage/uas.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index b610a2de4..0cdbcf825 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -1232,9 +1232,8 @@ static void uas_disconnect(struct usb_interface *intf)
  * hang on reboot when the device is still in uas mode. Note the reset is
  * necessary as some devices won't revert to usb-storage mode without it.
  */
-static void uas_shutdown(struct device *dev)
+static void uas_shutdown(struct usb_interface *intf)
 {
-	struct usb_interface *intf = to_usb_interface(dev);
 	struct usb_device *udev = interface_to_usbdev(intf);
 	struct Scsi_Host *shost = usb_get_intfdata(intf);
 	struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
@@ -1257,7 +1256,7 @@ static struct usb_driver uas_driver = {
 	.suspend = uas_suspend,
 	.resume = uas_resume,
 	.reset_resume = uas_reset_resume,
-	.driver.shutdown = uas_shutdown,
+	.shutdown = uas_shutdown,
 	.id_table = uas_usb_ids,
 };
 
-- 
2.43.0

Re: [PATCH v2 2/2] scsi: usb: uas: Implement the new shutdown callback

[gregkh]

On Sat, Jul 06, 2024 at 10:01:38AM +0000, Aditya Garg wrote:
> From: Kerem Karabay <kekrby@gmail.com>
> 
> This patch implements the new shutdown callback method added to
> usb_driver on the UAS driver.
> 
> Signed-off-by: Kerem Karabay <kekrby@gmail.com>
> Signed-off-by: Aditya Garg <gargaditya08@live.com>
> ---
>  drivers/usb/storage/uas.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)

Why the "scsi:" on the subject line?  This is not that directory :(

Re: [PATCH v2 2/2] scsi: usb: uas: Implement the new shutdown callback

[Aditya Garg]

> On 6 Jul 2024, at 3:39 PM, gregkh@linuxfoundation.org wrote:
> 
> On Sat, Jul 06, 2024 at 10:01:38AM +0000, Aditya Garg wrote:
>> From: Kerem Karabay <kekrby@gmail.com>
>> 
>> This patch implements the new shutdown callback method added to
>> usb_driver on the UAS driver.
>> 
>> Signed-off-by: Kerem Karabay <kekrby@gmail.com>
>> Signed-off-by: Aditya Garg <gargaditya08@live.com>
>> ---
>> drivers/usb/storage/uas.c | 5 ++---
>> 1 file changed, 2 insertions(+), 3 deletions(-)
> 
> Why the "scsi:" on the subject line?  This is not that directory :(
> 

I'll remove scsi: from the subject.

Re: [PATCH v2 2/2] scsi: usb: uas: Implement the new shutdown callback

[gregkh]

On Sat, Jul 06, 2024 at 10:01:38AM +0000, Aditya Garg wrote:
> From: Kerem Karabay <kekrby@gmail.com>
> 
> This patch implements the new shutdown callback method added to
> usb_driver on the UAS driver.

Again, says what it does, but not why.

Re: [PATCH v2 2/2] scsi: usb: uas: Implement the new shutdown callback

[Aditya Garg]

> On 6 Jul 2024, at 3:39 PM, gregkh@linuxfoundation.org wrote:
> 
> On Sat, Jul 06, 2024 at 10:01:38AM +0000, Aditya Garg wrote:
>> From: Kerem Karabay <kekrby@gmail.com>
>> 
>> This patch implements the new shutdown callback method added to
>> usb_driver on the UAS driver.
> 
> Again, says what it does, but not why.
> 

A standard implementation of shutdown callback has been implemented
for USB drivers. Since the UAS driver implements a shutdown callback
this patch enables it to use the new standard implementation.

Now looks fine?

Is the body of the first patch fine?

Re: [PATCH v2 2/2] scsi: usb: uas: Implement the new shutdown callback

[Aditya Garg]

> On 6 Jul 2024, at 3:39 PM, gregkh@linuxfoundation.org wrote:
> 
> On Sat, Jul 06, 2024 at 10:01:38AM +0000, Aditya Garg wrote:
>> From: Kerem Karabay <kekrby@gmail.com>
>> 
>> This patch implements the new shutdown callback method added to
>> usb_driver on the UAS driver.
> 
> Again, says what it does, but not why.
> 

Sent a v3:

https://lore.kernel.org/all/58227E2C-1886-40AD-8F80-7C618EF2D8F2@live.com/T/#t