net: wwan: core: Return poll error in case of port removal

Ensure that the poll system call returns proper error flags when port
is removed (nullified port ops), allowing user side to properly fail,
without further read or write.

Fixes: 9a44c1cc6388 ("net: Add a WWAN subsystem")
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
index 5be5e1e3534cf17d418ea88861954ccac96b9cdc..cff04e532c1e0778800c0bb255f1a61bf20d8e59 100644 (file)
--- a/drivers/net/wwan/wwan_core.c
+++ b/drivers/net/wwan/wwan_core.c
@@ -508,6 +508,8 @@ static __poll_t wwan_port_fops_poll(struct file *filp, poll_table *wait)
                mask |= EPOLLOUT | EPOLLWRNORM;
        if (!is_read_blocked(port))
                mask |= EPOLLIN | EPOLLRDNORM;
+       if (!port->ops)
+               mask |= EPOLLHUP | EPOLLERR;
 
        return mask;
 }