[PATCH 4/5] rpmsg: wakeup poll to notify signal update

Arun Kumar Neelakantam
2018-10-03T11:35:16Z

Add support to wait on poll to get signal notifications.
Send POLLPRI mask to indicate the signal change.

Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
drivers/rpmsg/rpmsg_char.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index c983d6c..aee5561 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -64,6 +64,7 @@ struct rpmsg_ctrldev {
* @queue_lock: synchronization of @queue operations
* @queue: incoming message queue
* @readq: wait object for incoming queue
+ * @sig_pending:state of signal notification
*/
struct rpmsg_eptdev {
struct device dev;
@@ -78,6 +79,8 @@ struct rpmsg_eptdev {
spinlock_t queue_lock;
struct sk_buff_head queue;
wait_queue_head_t readq;
+
+ atomic_t sig_pending;
};

static int rpmsg_eptdev_destroy(struct device *dev, void *data)
@@ -125,6 +128,12 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
static int rpmsg_sigs_cb(struct rpmsg_device *rpdev, void *priv,
u32 old, u32 new)
{
+ struct rpmsg_eptdev *eptdev = priv;
+
+ atomic_set(&eptdev->sig_pending, 1);
+
+ /* wake up any blocking processes, waiting for signal notification */
+ wake_up_interruptible(&eptdev->readq);
return 0;
}

@@ -164,6 +173,7 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
eptdev->ept = NULL;
}
mutex_unlock(&eptdev->ept_lock);
+ atomic_set(&eptdev->sig_pending, 0);

/* Discard all SKBs */
while (!skb_queue_empty(&eptdev->queue)) {
@@ -270,6 +280,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
if (!skb_queue_empty(&eptdev->queue))
mask |= EPOLLIN | EPOLLRDNORM;

+ if (atomic_read(&eptdev->sig_pending))
+ mask |= POLLPRI;
+
mask |= rpmsg_poll(eptdev->ept, filp, wait);

return mask;
@@ -318,6 +331,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
ret = rpmsg_get_sigs(eptdev->ept, &lsigs, &rsigs);
if (!ret)
ret = put_user(rsigs, (u32 *)arg);
+ atomic_set(&eptdev->sig_pending, 0);
break;