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, changed the driver code to use Wait Queue.
Signed-off-by: Bongsu Jeon <bongsu.jeon@xxxxxxxxxxx>
---
drivers/nfc/virtual_ncidev.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
index 2ee0ec4bb739..1953904176a2 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;
}
@@ -76,12 +79,11 @@ static ssize_t virtual_ncidev_read(struct file *file, char __user *buf,
{
size_t actual_len;
- mutex_lock(&nci_mutex);
- if (!send_buff) {
- mutex_unlock(&nci_mutex);
+ wait_event_interruptible(wq, send_buff);
+ if (!send_buff)
return 0;
- }
+ mutex_lock(&nci_mutex);
actual_len = min_t(size_t, count, send_buff->len);
if (copy_to_user(buf, send_buff->data, actual_len)) {
--
2.32.0
