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Commit cb88a1b8 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: fix the clear_tt_buffer interface 



This patch (as1255) updates the interface for calling
usb_hub_clear_tt_buffer().  Even the name of the function is changed!

When an async URB (i.e., Control or Bulk) going through a high-speed
hub to a non-high-speed device is cancelled or fails, the hub's
Transaction Translator buffer may be left busy still trying to
complete the transaction.  The buffer has to be cleared; that's what
usb_hub_clear_tt_buffer() does.

It isn't safe to send any more URBs to the same endpoint until the TT
buffer is fully clear.  Therefore the HCD needs to be told when the
Clear-TT-Buffer request has finished.  This patch adds a callback
method to struct hc_driver for that purpose, and makes the hub driver
invoke the callback at the proper time.

The patch also changes a couple of names; "hub_tt_kevent" and
"tt.kevent" now look rather antiquated.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 87ea8c88

drivers/usb/core/hcd.h

+4 −0
Original line number Diff line number Diff line
@@ -227,6 +227,10 @@ struct hc_driver { 
		/* has a port been handed over to a companion? */

	int	(*port_handed_over)(struct usb_hcd *, int);



		/* CLEAR_TT_BUFFER completion callback */

	void	(*clear_tt_buffer_complete)(struct usb_hcd *,

				struct usb_host_endpoint *);



	/* xHCI specific functions */

		/* Called by usb_alloc_dev to alloc HC device structures */

	int	(*alloc_dev)(struct usb_hcd *, struct usb_device *);

drivers/usb/core/hub.c

+26 −14
Original line number Diff line number Diff line
@@ -450,10 +450,10 @@ hub_clear_tt_buffer (struct usb_device *hdev, u16 devinfo, u16 tt) 
 * talking to TTs must queue control transfers (not just bulk and iso), so

 * both can talk to the same hub concurrently.

 */

static void hub_tt_kevent (struct work_struct *work)

static void hub_tt_work(struct work_struct *work)

{

	struct usb_hub		*hub =

		container_of(work, struct usb_hub, tt.kevent);

		container_of(work, struct usb_hub, tt.clear_work);

	unsigned long		flags;

	int			limit = 100;
@@ -462,6 +462,7 @@ static void hub_tt_kevent (struct work_struct *work) 
		struct list_head	*next;

		struct usb_tt_clear	*clear;

		struct usb_device	*hdev = hub->hdev;

		const struct hc_driver	*drv;

		int			status;



		next = hub->tt.clear_list.next;
@@ -471,21 +472,25 @@ static void hub_tt_kevent (struct work_struct *work) 
		/* drop lock so HCD can concurrently report other TT errors */

		spin_unlock_irqrestore (&hub->tt.lock, flags);

		status = hub_clear_tt_buffer (hdev, clear->devinfo, clear->tt);

		spin_lock_irqsave (&hub->tt.lock, flags);



		if (status)

			dev_err (&hdev->dev,

				"clear tt %d (%04x) error %d\n",

				clear->tt, clear->devinfo, status);



		/* Tell the HCD, even if the operation failed */

		drv = clear->hcd->driver;

		if (drv->clear_tt_buffer_complete)

			(drv->clear_tt_buffer_complete)(clear->hcd, clear->ep);



		kfree(clear);

		spin_lock_irqsave(&hub->tt.lock, flags);

	}

	spin_unlock_irqrestore (&hub->tt.lock, flags);

}



/**

 * usb_hub_tt_clear_buffer - clear control/bulk TT state in high speed hub

 * @udev: the device whose split transaction failed

 * @pipe: identifies the endpoint of the failed transaction

 * usb_hub_clear_tt_buffer - clear control/bulk TT state in high speed hub

 * @urb: an URB associated with the failed or incomplete split transaction

 *

 * High speed HCDs use this to tell the hub driver that some split control or

 * bulk transaction failed in a way that requires clearing internal state of
@@ -495,8 +500,10 @@ static void hub_tt_kevent (struct work_struct *work) 
 * It may not be possible for that hub to handle additional full (or low)

 * speed transactions until that state is fully cleared out.

 */

void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe)

int usb_hub_clear_tt_buffer(struct urb *urb)

{

	struct usb_device	*udev = urb->dev;

	int			pipe = urb->pipe;

	struct usb_tt		*tt = udev->tt;

	unsigned long		flags;

	struct usb_tt_clear	*clear;
@@ -508,7 +515,7 @@ void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe) 
	if ((clear = kmalloc (sizeof *clear, GFP_ATOMIC)) == NULL) {

		dev_err (&udev->dev, "can't save CLEAR_TT_BUFFER state\n");

		/* FIXME recover somehow ... RESET_TT? */

		return;

		return -ENOMEM;

	}



	/* info that CLEAR_TT_BUFFER needs */
@@ -521,13 +528,18 @@ void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe) 
	if (usb_pipein (pipe))

		clear->devinfo |= 1 << 15;



	/* info for completion callback */

	clear->hcd = bus_to_hcd(udev->bus);

	clear->ep = urb->ep;



	/* tell keventd to clear state for this TT */

	spin_lock_irqsave (&tt->lock, flags);

	list_add_tail (&clear->clear_list, &tt->clear_list);

	schedule_work (&tt->kevent);

	schedule_work(&tt->clear_work);

	spin_unlock_irqrestore (&tt->lock, flags);

	return 0;

}

EXPORT_SYMBOL_GPL(usb_hub_tt_clear_buffer);

EXPORT_SYMBOL_GPL(usb_hub_clear_tt_buffer);



/* If do_delay is false, return the number of milliseconds the caller

 * needs to delay.
@@ -818,7 +830,7 @@ static void hub_quiesce(struct usb_hub *hub, enum hub_quiescing_type type) 
	if (hub->has_indicators)

		cancel_delayed_work_sync(&hub->leds);

	if (hub->tt.hub)

		cancel_work_sync(&hub->tt.kevent);

		cancel_work_sync(&hub->tt.clear_work);

}



/* caller has locked the hub device */
@@ -935,7 +947,7 @@ static int hub_configure(struct usb_hub *hub, 


	spin_lock_init (&hub->tt.lock);

	INIT_LIST_HEAD (&hub->tt.clear_list);

	INIT_WORK (&hub->tt.kevent, hub_tt_kevent);

	INIT_WORK(&hub->tt.clear_work, hub_tt_work);

	switch (hdev->descriptor.bDeviceProtocol) {

		case 0:

			break;

drivers/usb/core/hub.h

+4 −2
Original line number Diff line number Diff line
@@ -188,16 +188,18 @@ struct usb_tt { 
	/* for control/bulk error recovery (CLEAR_TT_BUFFER) */

	spinlock_t		lock;

	struct list_head	clear_list;	/* of usb_tt_clear */

	struct work_struct			kevent;

	struct work_struct	clear_work;

};



struct usb_tt_clear {

	struct list_head	clear_list;

	unsigned		tt;

	u16			devinfo;

	struct usb_hcd		*hcd;

	struct usb_host_endpoint	*ep;

};



extern void usb_hub_tt_clear_buffer(struct usb_device *dev, int pipe);

extern int usb_hub_clear_tt_buffer(struct urb *urb);

extern void usb_ep0_reinit(struct usb_device *);



#endif /* __LINUX_HUB_H */

drivers/usb/host/ehci-q.c

+1 −1
Original line number Diff line number Diff line
@@ -215,7 +215,7 @@ static int qtd_copy_status ( 
			/* REVISIT ARC-derived cores don't clear the root

			 * hub TT buffer in this way...

			 */

			usb_hub_tt_clear_buffer (urb->dev, urb->pipe);

			usb_hub_clear_tt_buffer(urb);

		}

	}