Merge branch 'RPMSG-WWAN-CTRL-driver'

Stephan Gerhold says:

====================
net: wwan: Add RPMSG WWAN CTRL driver

This patch series adds a WWAN "control" driver for the remote processor
messaging (rpmsg) subsystem. This subsystem allows communicating with
an integrated modem DSP on many Qualcomm SoCs, e.g. MSM8916 or MSM8974.

The driver is a fairly simple glue layer between WWAN and RPMSG
and is mostly based on the existing mhi_wwan_ctrl.c and rpmsg_char.c.

For more information, see commit message in PATCH 2/3.

I already posted a RFC for this a while ago:
https://lore.kernel.org/linux-arm-msm/YLfL9Q+4860uqS8f@gerhold.net/
and now I'm looking for some feedback for the actual changes. :)

Changes in v3:
  - PATCH 2/3: Clarify commit message
  - PATCH 3/3: Fix build error for cdc-wdm.c, use extra tx_blocking() op instead
v2: https://lore.kernel.org/netdev/20210618075243.42046-1-stephan@gerhold.net/

Changes in v2: Only in PATCH 3/3
  - Fix EPOLLOUT being always set even if poll op is defined
  - Rename poll() op -> tx_poll() since it should be only used for TX
v1: https://lore.kernel.org/netdev/20210615133229.213064-1-stephan@gerhold.net/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 4 deletions

diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
index 7e728042fc41..165afec1dbd1 100644
--- a/drivers/net/wwan/wwan_core.c
+++ b/drivers/net/wwan/wwan_core.c
@@ -500,7 +500,8 @@ static void wwan_port_op_stop(struct wwan_port *port)
 	mutex_unlock(&port->ops_lock);
 }
 
-static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb)
+static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb,
+			   bool nonblock)
 {
 	int ret;
 
@@ -510,7 +511,10 @@ static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb)
 		goto out_unlock;
 	}
 
-	ret = port->ops->tx(port, skb);
+	if (nonblock || !port->ops->tx_blocking)
+		ret = port->ops->tx(port, skb);
+	else
+		ret = port->ops->tx_blocking(port, skb);
 
 out_unlock:
 	mutex_unlock(&port->ops_lock);
@@ -637,7 +641,7 @@ static ssize_t wwan_port_fops_write(struct file *filp, const char __user *buf,
 		return -EFAULT;
 	}
 
-	ret = wwan_port_op_tx(port, skb);
+	ret = wwan_port_op_tx(port, skb, !!(filp->f_flags & O_NONBLOCK));
 	if (ret) {
 		kfree_skb(skb);
 		return ret;
@@ -653,12 +657,16 @@ static __poll_t wwan_port_fops_poll(struct file *filp, poll_table *wait)
 
 	poll_wait(filp, &port->waitqueue, wait);
 
-	if (!is_write_blocked(port))
+	mutex_lock(&port->ops_lock);
+	if (port->ops && port->ops->tx_poll)
+		mask |= port->ops->tx_poll(port, filp, wait);
+	else if (!is_write_blocked(port))
 		mask |= EPOLLOUT | EPOLLWRNORM;
 	if (!is_read_blocked(port))
 		mask |= EPOLLIN | EPOLLRDNORM;
 	if (!port->ops)
 		mask |= EPOLLHUP | EPOLLERR;
+	mutex_unlock(&port->ops_lock);
 
 	return mask;
 }