From: Bongsu Jeon <bongsu.jeon@xxxxxxxxxxx>
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@xxxxxxxxxxx>
---
drivers/nfc/virtual_ncidev.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
index 2ee0ec4bb739..221fa3bb8705 100644
--- a/drivers/nfc/virtual_ncidev.c
+++ b/drivers/nfc/virtual_ncidev.c
@@ -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);
--
2.32.0
