From f03f5979945c573801c25ba3089ef17c4d7edc61 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 11 Aug 2011 16:25:49 +0200 Subject: [PATCH] tracing/filter: Unify predicate tree walking, change check_pred_tree function to use it Adding walk_pred_tree function to be used for walking throught the filter predicates. For each predicate the callback function is called, allowing users to add their own functionality or customize their way through the filter predicates. Changing check_pred_tree function to use walk_pred_tree. Signed-off-by: Jiri Olsa Link: http://lkml.kernel.org/r/1313072754-4620-6-git-send-email-jolsa@redhat.com Signed-off-by: Steven Rostedt --- kernel/trace/trace_events_filter.c | 137 +++++++++++++++++++++++-------------- 1 file changed, 86 insertions(+), 51 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 0948905..5b889d4 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -381,6 +381,63 @@ get_pred_parent(struct filter_pred *pred, struct filter_pred *preds, return pred; } +enum walk_return { + WALK_PRED_ABORT, + WALK_PRED_PARENT, + WALK_PRED_DEFAULT, +}; + +typedef int (*filter_pred_walkcb_t) (enum move_type move, + struct filter_pred *pred, + int *err, void *data); + +static int walk_pred_tree(struct filter_pred *preds, + struct filter_pred *root, + filter_pred_walkcb_t cb, void *data) +{ + struct filter_pred *pred = root; + enum move_type move = MOVE_DOWN; + int done = 0; + + if (!preds) + return -EINVAL; + + do { + int err = 0, ret; + + ret = cb(move, pred, &err, data); + if (ret == WALK_PRED_ABORT) + return err; + if (ret == WALK_PRED_PARENT) + goto get_parent; + + switch (move) { + case MOVE_DOWN: + if (pred->left != FILTER_PRED_INVALID) { + pred = &preds[pred->left]; + continue; + } + goto get_parent; + case MOVE_UP_FROM_LEFT: + pred = &preds[pred->right]; + move = MOVE_DOWN; + continue; + case MOVE_UP_FROM_RIGHT: + get_parent: + if (pred == root) + break; + pred = get_pred_parent(pred, preds, + pred->parent, + &move); + continue; + } + done = 1; + } while (!done); + + /* We are fine. */ + return 0; +} + /* * A series of AND or ORs where found together. Instead of * climbing up and down the tree branches, an array of the @@ -1321,6 +1378,23 @@ static int count_preds(struct filter_parse_state *ps) return n_preds; } +struct check_pred_data { + int count; + int max; +}; + +static int check_pred_tree_cb(enum move_type move, struct filter_pred *pred, + int *err, void *data) +{ + struct check_pred_data *d = data; + + if (WARN_ON(d->count++ > d->max)) { + *err = -EINVAL; + return WALK_PRED_ABORT; + } + return WALK_PRED_DEFAULT; +} + /* * The tree is walked at filtering of an event. If the tree is not correctly * built, it may cause an infinite loop. Check here that the tree does @@ -1329,58 +1403,19 @@ static int count_preds(struct filter_parse_state *ps) static int check_pred_tree(struct event_filter *filter, struct filter_pred *root) { - struct filter_pred *preds; - struct filter_pred *pred; - enum move_type move = MOVE_DOWN; - int count = 0; - int done = 0; - int max; - - /* - * The max that we can hit a node is three times. - * Once going down, once coming up from left, and - * once coming up from right. This is more than enough - * since leafs are only hit a single time. - */ - max = 3 * filter->n_preds; - - preds = filter->preds; - if (!preds) - return -EINVAL; - pred = root; - - do { - if (WARN_ON(count++ > max)) - return -EINVAL; - - switch (move) { - case MOVE_DOWN: - if (pred->left != FILTER_PRED_INVALID) { - pred = &preds[pred->left]; - continue; - } - /* A leaf at the root is just a leaf in the tree */ - if (pred == root) - break; - pred = get_pred_parent(pred, preds, - pred->parent, &move); - continue; - case MOVE_UP_FROM_LEFT: - pred = &preds[pred->right]; - move = MOVE_DOWN; - continue; - case MOVE_UP_FROM_RIGHT: - if (pred == root) - break; - pred = get_pred_parent(pred, preds, - pred->parent, &move); - continue; - } - done = 1; - } while (!done); + struct check_pred_data data = { + /* + * The max that we can hit a node is three times. + * Once going down, once coming up from left, and + * once coming up from right. This is more than enough + * since leafs are only hit a single time. + */ + .max = 3 * filter->n_preds, + .count = 0, + }; - /* We are fine. */ - return 0; + return walk_pred_tree(filter->preds, root, + check_pred_tree_cb, &data); } static int count_leafs(struct filter_pred *preds, struct filter_pred *root) -- 2.7.4