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nfc: virtual_ncidev: Use wait queue instead of polling

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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: Bongsu Jeon <bongsu.jeon@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Bongsu Jeon 2021-08-17 06:28:11 -07:00 committed by David S. Miller
parent ec18e84554
commit 8675569d73
1 changed files with 7 additions and 2 deletions
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9
drivers/nfc/virtual_ncidev.c
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@ -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);