On Mon, 1 Dec 2014 22:57:25 -0500
Steven Rostedt <rost...@goodmis.org> wrote:
> On Mon, 1 Dec 2014 19:52:11 -0800
> Alexei Starovoitov <a...@plumgrid.com> wrote:
>
> > yeah. teaching tree walk to do (state & 2048) == 0 is not trivial,
> > since it doesn't have a concept of value of expression.
> > Doing !(state & 2048) is probably a bit easier, since there
> > are hacks for 'not' already.
>
> That's exactly what I was looking at doing. If I can get something
> working without spending more than an hour or two, I may even push it
> for this release cycle.
Actually, this was rather trivial. It took me longer because I was
doing this half asleep, but it seems to work.
Note, this is a major beta patch. It probably doesn't work with ANDS
and ORS, that is !(x == 1 && y == 2) probably doesn't work, but this
should: !(x == 1), and so should !(state & 2048).
I'll clean this up and get it ready for 3.19.
Cheers!
-- Steve
diff --git a/kernel/trace/trace_events_filter.c
b/kernel/trace/trace_events_filter.c
index 7a8c1528e141..aee7b743c9df 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -37,6 +37,7 @@ enum filter_op_ids
{
OP_OR,
OP_AND,
+ OP_NOT,
OP_GLOB,
OP_NE,
OP_EQ,
@@ -59,6 +60,7 @@ struct filter_op {
static struct filter_op filter_ops[] = {
{ OP_OR, "||", 1 },
{ OP_AND, "&&", 2 },
+ { OP_NOT, "!", 3 },
{ OP_GLOB, "~", 4 },
{ OP_NE, "!=", 4 },
{ OP_EQ, "==", 4 },
@@ -166,7 +168,7 @@ static int filter_pred_##type(struct filter_pred *pred,
void *event) \
break; \
} \
\
- return match; \
+ return match == !pred->not; \
}
#define DEFINE_EQUALITY_PRED(size) \
@@ -565,7 +567,7 @@ int filter_match_preds(struct event_filter *filter, void
*rec)
data.preds = preds = rcu_dereference_sched(filter->preds);
ret = walk_pred_tree(preds, root, filter_match_preds_cb, &data);
WARN_ON(ret);
- return data.match;
+ return !!data.match;
}
EXPORT_SYMBOL_GPL(filter_match_preds);
@@ -1028,7 +1030,7 @@ static int init_pred(struct filter_parse_state *ps,
}
if (pred->op == OP_NE)
- pred->not = 1;
+ pred->not ^= 1;
pred->fn = fn;
return 0;
@@ -1590,6 +1592,16 @@ static int replace_preds(struct ftrace_event_call *call,
continue;
}
+ if (elt->op == OP_NOT) {
+ if (!n_preds) {
+ err = -EINVAL;
+ goto fail;
+ }
+ if (!dry_run)
+ filter->preds[n_preds - 1].not ^= 1;
+ continue;
+ }
+
if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) {
parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
err = -ENOSPC;
--
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