From c77625fdd7583c22bfc8fa3d9bd166770653fffb Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Sat, 4 Oct 2008 22:04:44 +0200
Subject: [PATCH] --- yaml --- r: 116678 b: refs/heads/master c:
 c2931e05ec5965597cbfb79ad332d4a29aeceb23 h: refs/heads/master v: v3

---
 [refs]                     |  2 +-
 trunk/kernel/trace/trace.c | 13 ++++++++++---
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index 8db9c7c7b75d..d2cbfab6d8a2 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3ea2e6d71aafe35b8aaf89ed711a283815acfae6
+refs/heads/master: c2931e05ec5965597cbfb79ad332d4a29aeceb23
diff --git a/trunk/kernel/trace/trace.c b/trunk/kernel/trace/trace.c
index caa4051ce778..78d56614c95b 100644
--- a/trunk/kernel/trace/trace.c
+++ b/trunk/kernel/trace/trace.c
@@ -2381,9 +2381,11 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
 	struct tracer *t;
 	char buf[max_tracer_type_len+1];
 	int i;
+	size_t ret;
 
 	if (cnt > max_tracer_type_len)
 		cnt = max_tracer_type_len;
+	ret = cnt;
 
 	if (copy_from_user(&buf, ubuf, cnt))
 		return -EFAULT;
@@ -2399,7 +2401,11 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
 		if (strcmp(t->name, buf) == 0)
 			break;
 	}
-	if (!t || t == current_trace)
+	if (!t) {
+		ret = -EINVAL;
+		goto out;
+	}
+	if (t == current_trace)
 		goto out;
 
 	if (current_trace && current_trace->reset)
@@ -2412,9 +2418,10 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
  out:
 	mutex_unlock(&trace_types_lock);
 
-	filp->f_pos += cnt;
+	if (ret == cnt)
+		filp->f_pos += cnt;
 
-	return cnt;
+	return ret;
 }
 
 static ssize_t