提交 51a2f077 编写于 作者: O Oliver Neukum 提交者: Greg Kroah-Hartman

USB: introduce usb_anchor

- introduction of usb_anchor and its methods
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
上级 ffcdc18d
......@@ -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);
......
......@@ -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);
}
}
......@@ -100,8 +103,60 @@ struct urb * usb_get_urb(struct urb *urb)
kref_get(&urb->kref);
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);
......@@ -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);
......
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