tracing/kprobes: Support longer (>128 bytes) command

Expand command line buffer of kprobe-tracer to 4096 bytes.

Reported-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20110204125159.9507.20895.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

kernel/trace/trace_kprobe.c

@@ -1129,7 +1129,7 @@ static int command_trace_probe(const char *buf)
 	return ret;
 }
 
-#define WRITE_BUFSIZE 128
+#define WRITE_BUFSIZE 4096
 
 static ssize_t probes_write(struct file *file, const char __user *buffer,
 			    size_t count, loff_t *ppos)