Ted noticed that he could not filter on an event for a bit being cleared. That's because the filtering logic only tests event fields with a limited number of comparisons which, for bit logic, only include "&", which can test if a bit is set, but there's no good way to see if a bit is clear.
This adds a way to do: !(field & 2048) Which returns true if the bit is not set, and false otherwise. Note, currently !(field1 == 10 && field2 == 15) is not supported. That is, the 'not' only works for direct comparisons, not for the AND and OR logic. Link: http://lkml.kernel.org/r/[email protected] Suggested-by: "Theodore Ts'o" <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- kernel/trace/trace_events_filter.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 7a8c1528e141..9ddbf0c05340 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) \ @@ -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; -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
