From b3e6cdfb71b60c2acc521cb807a955100081b7b8 Mon Sep 17 00:00:00 2001
From: David Herrmann <dh.herrmann@googlemail.com>
Date: Sun, 10 Jun 2012 15:16:16 +0200
Subject: [PATCH] --- yaml --- r: 316068 b: refs/heads/master c:
 d937ae5fae17e63aaa97f029be221a6516b25475 h: refs/heads/master v: v3

---
 [refs]                   |  2 +-
 trunk/drivers/hid/uhid.c | 46 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index e85aac3413dc..f72b0c2bff9a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1f9dec1e0164b48da9b268a02197f38caa69b118
+refs/heads/master: d937ae5fae17e63aaa97f029be221a6516b25475
diff --git a/trunk/drivers/hid/uhid.c b/trunk/drivers/hid/uhid.c
index b1a477f8260c..93860826d629 100644
--- a/trunk/drivers/hid/uhid.c
+++ b/trunk/drivers/hid/uhid.c
@@ -28,6 +28,7 @@
 #define UHID_BUFSIZE	32
 
 struct uhid_device {
+	struct mutex devlock;
 	struct hid_device *hid;
 
 	wait_queue_head_t waitq;
@@ -81,6 +82,7 @@ static int uhid_char_open(struct inode *inode, struct file *file)
 	if (!uhid)
 		return -ENOMEM;
 
+	mutex_init(&uhid->devlock);
 	spin_lock_init(&uhid->qlock);
 	init_waitqueue_head(&uhid->waitq);
 
@@ -106,7 +108,49 @@ static int uhid_char_release(struct inode *inode, struct file *file)
 static ssize_t uhid_char_read(struct file *file, char __user *buffer,
 				size_t count, loff_t *ppos)
 {
-	return 0;
+	struct uhid_device *uhid = file->private_data;
+	int ret;
+	unsigned long flags;
+	size_t len;
+
+	/* they need at least the "type" member of uhid_event */
+	if (count < sizeof(__u32))
+		return -EINVAL;
+
+try_again:
+	if (file->f_flags & O_NONBLOCK) {
+		if (uhid->head == uhid->tail)
+			return -EAGAIN;
+	} else {
+		ret = wait_event_interruptible(uhid->waitq,
+						uhid->head != uhid->tail);
+		if (ret)
+			return ret;
+	}
+
+	ret = mutex_lock_interruptible(&uhid->devlock);
+	if (ret)
+		return ret;
+
+	if (uhid->head == uhid->tail) {
+		mutex_unlock(&uhid->devlock);
+		goto try_again;
+	} else {
+		len = min(count, sizeof(**uhid->outq));
+		if (copy_to_user(buffer, &uhid->outq[uhid->tail], len)) {
+			ret = -EFAULT;
+		} else {
+			kfree(uhid->outq[uhid->tail]);
+			uhid->outq[uhid->tail] = NULL;
+
+			spin_lock_irqsave(&uhid->qlock, flags);
+			uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
+			spin_unlock_irqrestore(&uhid->qlock, flags);
+		}
+	}
+
+	mutex_unlock(&uhid->devlock);
+	return ret ? ret : len;
 }
 
 static ssize_t uhid_char_write(struct file *file, const char __user *buffer,