From: Marcel Holtmann <marcel@holtmann.org>
Date: Wed, 4 Dec 2019 02:43:55 +0000 (+0100)
Subject: HID: uhid: Fix returning EPOLLOUT from uhid_char_poll
X-Git-Tag: v4.4.210~22
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=7a887f88482b21afad5333d7959ed66332b8a764;p=thirdparty%2Fkernel%2Fstable.git

HID: uhid: Fix returning EPOLLOUT from uhid_char_poll

commit be54e7461ffdc5809b67d2aeefc1ddc9a91470c7 upstream.

Always return EPOLLOUT from uhid_char_poll to allow polling /dev/uhid
for writable state.

Fixes: 1f9dec1e0164 ("HID: uhid: allow poll()'ing on uhid devices")
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index f6863adc15ad4..ea0c860ee8424 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -26,6 +26,7 @@
 #include <linux/uhid.h>
 #include <linux/wait.h>
 #include <linux/uaccess.h>
+#include <linux/eventpoll.h>
 
 #define UHID_NAME	"uhid"
 #define UHID_BUFSIZE	32
@@ -774,7 +775,7 @@ static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
 	if (uhid->head != uhid->tail)
 		return POLLIN | POLLRDNORM;
 
-	return 0;
+	return EPOLLOUT | EPOLLWRNORM;
 }
 
 static const struct file_operations uhid_fops = {