USB: introduce usb_anchor (51a2f077) · Commits · EulixOS / Software / Kernel

drivers/usb/core/hcd.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1410,6 +1410,8 @@ void usb_hcd_giveback_urb (struct usb_hcd hcd, struct urb urb)
		}

		usbmon_urb_complete (&hcd->self, urb);
		usb_unanchor_urb(urb);

		/* pass ownership to the completion handler */
		urb->complete (urb);
		atomic_dec (&urb->use_count);

drivers/usb/core/urb.c

+99 −3

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@
		#include <linux/slab.h>
		#include <linux/init.h>
		#include <linux/usb.h>
		#include <linux/wait.h>
		#include "hcd.h"

		#define to_urb(d) container_of(d, struct urb, kref)
		@@ -11,6 +12,7 @@
		static void urb_destroy(struct kref *kref)
		{
		struct urb *urb = to_urb(kref);

		kfree(urb);
		}

		@@ -34,6 +36,7 @@ void usb_init_urb(struct urb *urb)
		memset(urb, 0, sizeof(*urb));
		kref_init(&urb->kref);
		spin_lock_init(&urb->lock);
		INIT_LIST_HEAD(&urb->anchor_list);
		}
		}

		@@ -101,6 +104,58 @@ struct urb * usb_get_urb(struct urb *urb)
		return urb;
		}

		/**
		* usb_anchor_urb - anchors an URB while it is processed
		* @urb: pointer to the urb to anchor
		* @anchor: pointer to the anchor
		*
		* This can be called to have access to URBs which are to be executed
		* without bothering to track them
		*/
		void usb_anchor_urb(struct urb urb, struct usb_anchor anchor)
		{
		unsigned long flags;

		spin_lock_irqsave(&anchor->lock, flags);
		usb_get_urb(urb);
		list_add_tail(&urb->anchor_list, &anchor->urb_list);
		urb->anchor = anchor;
		spin_unlock_irqrestore(&anchor->lock, flags);
		}
		EXPORT_SYMBOL_GPL(usb_anchor_urb);

		/**
		* usb_unanchor_urb - unanchors an URB
		* @urb: pointer to the urb to anchor
		*
		* Call this to stop the system keeping track of this URB
		*/
		void usb_unanchor_urb(struct urb *urb)
		{
		unsigned long flags;
		struct usb_anchor *anchor;

		if (!urb)
		return;

		anchor = urb->anchor;
		if (!anchor)
		return;

		spin_lock_irqsave(&anchor->lock, flags);
		if (unlikely(anchor != urb->anchor)) {
		/* we've lost the race to another thread */
		spin_unlock_irqrestore(&anchor->lock, flags);
		return;
		}
		urb->anchor = NULL;
		list_del(&urb->anchor_list);
		spin_unlock_irqrestore(&anchor->lock, flags);
		usb_put_urb(urb);
		if (list_empty(&anchor->urb_list))
		wake_up(&anchor->wait);
		}
		EXPORT_SYMBOL_GPL(usb_unanchor_urb);

		/-------------------------------------------------------------------/

		@@ -478,6 +533,48 @@ void usb_kill_urb(struct urb *urb)
		spin_unlock_irq(&urb->lock);
		}

		/**
		* usb_kill_anchored_urbs - cancel transfer requests en masse
		* @anchor: anchor the requests are bound to
		*
		* this allows all outstanding URBs to be killed starting
		* from the back of the queue
		*/
		void usb_kill_anchored_urbs(struct usb_anchor *anchor)
		{
		struct urb *victim;

		spin_lock_irq(&anchor->lock);
		while (!list_empty(&anchor->urb_list)) {
		victim = list_entry(anchor->urb_list.prev, struct urb, anchor_list);
		/* we must make sure the URB isn't freed before we kill it*/
		usb_get_urb(victim);
		spin_unlock_irq(&anchor->lock);
		/* this will unanchor the URB */
		usb_kill_urb(victim);
		usb_put_urb(victim);
		spin_lock_irq(&anchor->lock);
		}
		spin_unlock_irq(&anchor->lock);
		}
		EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);

		/**
		* usb_wait_anchor_empty_timeout - wait for an anchor to be unused
		* @anchor: the anchor you want to become unused
		* @timeout: how long you are willing to wait in milliseconds
		*
		* Call this is you want to be sure all an anchor's
		* URBs have finished
		*/
		int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
		unsigned int timeout)
		{
		return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list),
		msecs_to_jiffies(timeout));
		}
		EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);

		EXPORT_SYMBOL(usb_init_urb);
		EXPORT_SYMBOL(usb_alloc_urb);
		EXPORT_SYMBOL(usb_free_urb);
		@@ -485,4 +582,3 @@ EXPORT_SYMBOL(usb_get_urb);
		EXPORT_SYMBOL(usb_submit_urb);
		EXPORT_SYMBOL(usb_unlink_urb);
		EXPORT_SYMBOL(usb_kill_urb);

include/linux/usb.h

+22 −0

Original line number	Diff line number	Diff line
		@@ -1000,11 +1000,26 @@ struct usb_iso_packet_descriptor {

		struct urb;

		struct usb_anchor {
		struct list_head urb_list;
		wait_queue_head_t wait;
		spinlock_t lock;
		};

		static inline void init_usb_anchor(struct usb_anchor *anchor)
		{
		INIT_LIST_HEAD(&anchor->urb_list);
		init_waitqueue_head(&anchor->wait);
		spin_lock_init(&anchor->lock);
		}

		typedef void (usb_complete_t)(struct urb );

		/**
		* struct urb - USB Request Block
		* @urb_list: For use by current owner of the URB.
		* @anchor_list: membership in the list of an anchor
		* @anchor: to anchor URBs to a common mooring
		* @pipe: Holds endpoint number, direction, type, and more.
		* Create these values with the eight macros available;
		* usb_{snd,rcv}TYPEpipe(dev,endpoint), where the TYPE is "ctrl"
		@@ -1177,6 +1192,8 @@ struct urb
		/* public: documented fields in the urb that can be used by drivers */
		struct list_head urb_list; /* list head for use by the urb's
		* current owner */
		struct list_head anchor_list; /* the URB may be anchored by the driver */
		struct usb_anchor *anchor;
		struct usb_device dev; / (in) pointer to associated device */
		unsigned int pipe; /* (in) pipe information */
		int status; /* (return) non-ISO status */
		@@ -1312,6 +1329,11 @@ extern struct urb usb_get_urb(struct urb urb);
		extern int usb_submit_urb(struct urb *urb, gfp_t mem_flags);
		extern int usb_unlink_urb(struct urb *urb);
		extern void usb_kill_urb(struct urb *urb);
		extern void usb_kill_anchored_urbs(struct usb_anchor *anchor);
		extern void usb_anchor_urb(struct urb urb, struct usb_anchor anchor);
		extern void usb_unanchor_urb(struct urb *urb);
		extern int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
		unsigned int timeout);

		void usb_buffer_alloc (struct usb_device dev, size_t size,
		gfp_t mem_flags, dma_addr_t *dma);