From: Fabian Henneke <fabian.henneke@gmail.com>
Date: Tue, 9 Jul 2019 11:03:37 +0000 (+0200)
Subject: hidraw: Return EPOLLOUT from hidraw_poll
X-Git-Tag: v3.16.83~79
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dcec894fc7aea9b106aae4d04e71e9888150335e;p=thirdparty%2Fkernel%2Fstable.git

hidraw: Return EPOLLOUT from hidraw_poll

commit 378b80370aa1fe50f9c48a3ac8af3e416e73b89f upstream.

Always return EPOLLOUT from hidraw_poll when a device is connected.
This is safe since writes are always possible (but will always block).

hidraw does not support non-blocking writes and instead always calls
blocking backend functions on write requests. Hence, so far, a call to
poll never returned EPOLLOUT, which confuses tools like socat.

Signed-off-by: Fabian Henneke <fabian.henneke@gmail.com>
In-reply-to: <CA+hv5qkyis03CgYTWeWX9cr0my-d2Oe+aZo+mjmWRXgjrGqyrw@mail.gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
[bwh: Backported to 3.16: s/EPOLL/POLL/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 627a24d3ea7c5..27d2f5a48a11c 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -265,7 +265,7 @@ static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 
 	poll_wait(file, &list->hidraw->wait, wait);
 	if (list->head != list->tail)
-		return POLLIN | POLLRDNORM;
+		return POLLIN | POLLRDNORM | POLLOUT;
 	if (!list->hidraw->exist)
 		return POLLERR | POLLHUP;
 	return 0;