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Commit b1a31a5f authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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usb/gadget/NCM: Replace tasklet with softirq hrtimer 



The tx_tasklet tasklet is used in invoke the hrtimer (task_timer) in
softirq context. This can be also achieved without the tasklet but
with HRTIMER_MODE_SOFT as hrtimer mode.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Acked-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: keescook@chromium.org
Cc: linux-usb@vger.kernel.org
Link: http://lkml.kernel.org/r/20171221104205.7269-36-anna-maria@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent b03bbbe0

drivers/usb/gadget/function/f_ncm.c

+7 −23
Original line number Diff line number Diff line
@@ -73,9 +73,7 @@ struct f_ncm { 
	struct sk_buff			*skb_tx_ndp;

	u16				ndp_dgram_count;

	bool				timer_force_tx;

	struct tasklet_struct		tx_tasklet;

	struct hrtimer			task_timer;



	bool				timer_stopping;

};
@@ -1104,7 +1102,7 @@ static struct sk_buff *ncm_wrap_ntb(struct gether *port, 


		/* Delay the timer. */

		hrtimer_start(&ncm->task_timer, TX_TIMEOUT_NSECS,

			      HRTIMER_MODE_REL);

			      HRTIMER_MODE_REL_SOFT);



		/* Add the datagram position entries */

		ntb_ndp = skb_put_zero(ncm->skb_tx_ndp, dgram_idx_len);
@@ -1148,17 +1146,15 @@ static struct sk_buff *ncm_wrap_ntb(struct gether *port, 
}



/*

 * This transmits the NTB if there are frames waiting.

 * The transmit should only be run if no skb data has been sent

 * for a certain duration.

 */

static void ncm_tx_tasklet(unsigned long data)

static enum hrtimer_restart ncm_tx_timeout(struct hrtimer *data)

{

	struct f_ncm	*ncm = (void *)data;



	if (ncm->timer_stopping)

		return;

	struct f_ncm *ncm = container_of(data, struct f_ncm, task_timer);



	/* Only send if data is available. */

	if (ncm->skb_tx_data) {

	if (!ncm->timer_stopping && ncm->skb_tx_data) {

		ncm->timer_force_tx = true;



		/* XXX This allowance of a NULL skb argument to ndo_start_xmit
@@ -1171,16 +1167,6 @@ static void ncm_tx_tasklet(unsigned long data) 


		ncm->timer_force_tx = false;

	}

}



/*

 * The transmit should only be run if no skb data has been sent

 * for a certain duration.

 */

static enum hrtimer_restart ncm_tx_timeout(struct hrtimer *data)

{

	struct f_ncm *ncm = container_of(data, struct f_ncm, task_timer);

	tasklet_schedule(&ncm->tx_tasklet);

	return HRTIMER_NORESTART;

}
@@ -1513,8 +1499,7 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f) 
	ncm->port.open = ncm_open;

	ncm->port.close = ncm_close;



	tasklet_init(&ncm->tx_tasklet, ncm_tx_tasklet, (unsigned long) ncm);

	hrtimer_init(&ncm->task_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	hrtimer_init(&ncm->task_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);

	ncm->task_timer.function = ncm_tx_timeout;



	DBG(cdev, "CDC Network: %s speed IN/%s OUT/%s NOTIFY/%s\n",
@@ -1623,7 +1608,6 @@ static void ncm_unbind(struct usb_configuration *c, struct usb_function *f) 
	DBG(c->cdev, "ncm unbind\n");



	hrtimer_cancel(&ncm->task_timer);

	tasklet_kill(&ncm->tx_tasklet);



	ncm_string_defs[0].id = 0;

	usb_free_all_descriptors(f);