Commit 8675569d authored by Bongsu Jeon's avatar Bongsu Jeon Committed by David S. Miller
Browse files

nfc: virtual_ncidev: Use wait queue instead of polling 



In previous version, the user level virtual device application that used
this driver should have the polling scheme to read a NCI frame.
To remove this polling scheme, use Wait Queue.

Signed-off-by: default avatarBongsu Jeon <bongsu.jeon@samsung.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ec18e845

drivers/nfc/virtual_ncidev.c

+7 −2
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/module.h>

#include <linux/miscdevice.h>

#include <linux/mutex.h>

#include <linux/wait.h>

#include <net/nfc/nci_core.h>



enum virtual_ncidev_mode {
@@ -27,6 +28,7 @@ enum virtual_ncidev_mode { 
				 NFC_PROTO_ISO15693_MASK)



static enum virtual_ncidev_mode state;

static DECLARE_WAIT_QUEUE_HEAD(wq);

static struct miscdevice miscdev;

static struct sk_buff *send_buff;

static struct nci_dev *ndev;
@@ -61,6 +63,7 @@ static int virtual_nci_send(struct nci_dev *ndev, struct sk_buff *skb) 
	}

	send_buff = skb_copy(skb, GFP_KERNEL);

	mutex_unlock(&nci_mutex);

	wake_up_interruptible(&wq);



	return 0;

}
@@ -77,9 +80,11 @@ static ssize_t virtual_ncidev_read(struct file *file, char __user *buf, 
	size_t actual_len;



	mutex_lock(&nci_mutex);

	if (!send_buff) {

	while (!send_buff) {

		mutex_unlock(&nci_mutex);

		return 0;

		if (wait_event_interruptible(wq, send_buff))

			return -EFAULT;

		mutex_lock(&nci_mutex);

	}



	actual_len = min_t(size_t, count, send_buff->len);