tracing: Do not (ab)use trace_seq in event_id_read()
authorOleg Nesterov <oleg@redhat.com>
Thu, 18 Jul 2013 18:47:12 +0000 (20:47 +0200)
committerSteven Rostedt <rostedt@goodmis.org>
Fri, 19 Jul 2013 01:31:33 +0000 (21:31 -0400)
commitcd458ba9d5a5592d37b5145e560071e91ea762ac
treed6a560b077696e68584995ba23e10556fcebcd8d
parent7710b639953b791610f0022a7d52d9801c93b969
tracing: Do not (ab)use trace_seq in event_id_read()

event_id_read() has no reason to kmalloc "struct trace_seq"
(more than PAGE_SIZE!), it can use a small buffer instead.

Note: "if (*ppos) return 0" looks strange and even wrong,
simple_read_from_buffer() handles ppos != 0 case corrrectly.

And it seems that almost every user of trace_seq in this file
should be converted too. Unless you use seq_open(), trace_seq
buys nothing compared to the raw buffer, but it needs a bit
more memory and code.

Link: http://lkml.kernel.org/r/20130718184712.GA4786@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
kernel/trace/trace_events.c