tracing: Use seq_buf_used() in seq_buf_to_user() instead of len
commit 5ac48378414d ("tracing: Use trace_seq_used() and seq_buf_used()
instead of len") changed the tracing code to use trace_seq_used() and
seq_buf_used() instead of using the seq_buf len directly to avoid
overflow issues, but missed a spot in seq_buf_to_user() that makes use
of s->len.
Cleaned up the code a bit as well per suggestion of Steve Rostedt.
Link: http://lkml.kernel.org/r/1447703848-2951-1-git-send-email-jsnitsel@redhat.com
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/lib/seq_buf.c b/lib/seq_buf.c
index 5c94e10..cb18469 100644
--- a/lib/seq_buf.c
+++ b/lib/seq_buf.c
@@ -306,10 +306,12 @@
if (!cnt)
return 0;
- if (s->len <= s->readpos)
+ len = seq_buf_used(s);
+
+ if (len <= s->readpos)
return -EBUSY;
- len = seq_buf_used(s) - s->readpos;
+ len -= s->readpos;
if (cnt > len)
cnt = len;
ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);