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Commit 4e1b1bae authored by Jack Pham's avatar Jack Pham
Browse files

usb: diag: Replace kref_put_spinlock_irqsave() with kref_put_lock() 



The kref structure has been changed to use refcount_t instead of
atomic_t. But also a new API function kref_put_lock() was added.
We can use this in place of defining our own locking version of
kref_put().

Change-Id: I0f7dc0c7c24f2b8e577b3b67cdd9422c4bd35514
Signed-off-by: default avatarJack Pham <jackp@codeaurora.org>
parent 6f456763

drivers/usb/gadget/function/f_diag.c

+5 −41
Original line number Diff line number Diff line
@@ -206,39 +206,7 @@ static inline struct diag_context *func_to_diag(struct usb_function *f) 
	return container_of(f, struct diag_context, function);

}



/**

 * kref_put_spinlock_irqsave - decrement refcount for object.

 * @kref: object.

 * @release: pointer to the function that will clean up the object when the

 *	     last reference to the object is released.

 *	     This pointer is required, and it is not acceptable to pass kfree

 *	     in as this function.

 * @lock: lock to take in release case

 *

 * Behaves identical to kref_put with one exception.  If the reference count

 * drops to zero, the lock will be taken atomically wrt dropping the reference

 * count.  The release function has to call spin_unlock() without _irqrestore.

 */

static inline int kref_put_spinlock_irqsave(struct kref *kref,

		void (*release)(struct kref *kref),

		spinlock_t *lock)

{

	unsigned long flags;



	WARN_ON(release == NULL);

	if (atomic_add_unless(&kref->refcount, -1, 1))

		return 0;

	spin_lock_irqsave(lock, flags);

	if (atomic_dec_and_test(&kref->refcount)) {

		release(kref);

		local_irq_restore(flags);

		return 1;

	}

	spin_unlock_irqrestore(lock, flags);

	return 0;

}



/* Called with ctxt->lock held; i.e. only use with kref_put_spinlock_irqsave */

/* Called with ctxt->lock held; i.e. only use with kref_put_lock() */

static void diag_context_release(struct kref *kref)

{

	struct diag_context *ctxt =
@@ -321,8 +289,7 @@ static void diag_write_complete(struct usb_ep *ep, 
	if (ctxt->ch && ctxt->ch->notify)

		ctxt->ch->notify(ctxt->ch->priv, USB_DIAG_WRITE_DONE, d_req);



	kref_put_spinlock_irqsave(&ctxt->kref, diag_context_release,

			&ctxt->lock);

	kref_put_lock(&ctxt->kref, diag_context_release, &ctxt->lock);

}



static void diag_read_complete(struct usb_ep *ep,
@@ -344,8 +311,7 @@ static void diag_read_complete(struct usb_ep *ep, 
	if (ctxt->ch && ctxt->ch->notify)

		ctxt->ch->notify(ctxt->ch->priv, USB_DIAG_READ_DONE, d_req);



	kref_put_spinlock_irqsave(&ctxt->kref, diag_context_release,

			&ctxt->lock);

	kref_put_lock(&ctxt->kref, diag_context_release, &ctxt->lock);

}



/**
@@ -556,8 +522,7 @@ int usb_diag_read(struct usb_diag_ch *ch, struct diag_request *d_req) 
	/* make sure context is still valid after releasing lock */

	if (ctxt != ch->priv_usb) {

		usb_ep_free_request(out, req);

		kref_put_spinlock_irqsave(&ctxt->kref, diag_context_release,

				&ctxt->lock);

		kref_put_lock(&ctxt->kref, diag_context_release, &ctxt->lock);

		return -EIO;

	}
@@ -633,8 +598,7 @@ int usb_diag_write(struct usb_diag_ch *ch, struct diag_request *d_req) 
	/* make sure context is still valid after releasing lock */

	if (ctxt != ch->priv_usb) {

		usb_ep_free_request(in, req);

		kref_put_spinlock_irqsave(&ctxt->kref, diag_context_release,

				&ctxt->lock);

		kref_put_lock(&ctxt->kref, diag_context_release, &ctxt->lock);

		return -EIO;

	}