ftrace: Replace FTRACE_FL_NOTRACE flag with a hash of ignored functions
To prepare for the accounting system that will allow multiple users of the function tracer, having the FTRACE_FL_NOTRACE as a flag in the dyn_trace record does not make sense. All ftrace_ops will soon have a hash of functions they should trace and not trace. By making a global hash of functions not to trace makes this easier for the transition. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
Steven Rostedt
Родитель
94692349c4
Коммит
b448c4e3ae
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@ -149,7 +149,6 @@ enum {
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FTRACE_FL_FREE = (1 << 0),
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FTRACE_FL_FILTER = (1 << 1),
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FTRACE_FL_ENABLED = (1 << 2),
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FTRACE_FL_NOTRACE = (1 << 3),
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};
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struct dyn_ftrace {
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@ -57,6 +57,7 @@
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/* hash bits for specific function selection */
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#define FTRACE_HASH_BITS 7
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#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
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#define FTRACE_HASH_MAX_BITS 10
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/* ftrace_enabled is a method to turn ftrace on or off */
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int ftrace_enabled __read_mostly;
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@ -865,6 +866,22 @@ enum {
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FTRACE_START_FUNC_RET = (1 << 3),
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FTRACE_STOP_FUNC_RET = (1 << 4),
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};
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struct ftrace_func_entry {
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struct hlist_node hlist;
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unsigned long ip;
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};
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struct ftrace_hash {
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unsigned long size_bits;
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struct hlist_head *buckets;
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unsigned long count;
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};
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static struct hlist_head notrace_buckets[1 << FTRACE_HASH_MAX_BITS];
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static struct ftrace_hash notrace_hash = {
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.size_bits = FTRACE_HASH_MAX_BITS,
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.buckets = notrace_buckets,
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};
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static int ftrace_filtered;
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@ -889,6 +906,79 @@ static struct ftrace_page *ftrace_pages;
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static struct dyn_ftrace *ftrace_free_records;
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static struct ftrace_func_entry *
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ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
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{
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unsigned long key;
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struct ftrace_func_entry *entry;
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struct hlist_head *hhd;
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struct hlist_node *n;
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if (!hash->count)
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return NULL;
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if (hash->size_bits > 0)
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key = hash_long(ip, hash->size_bits);
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else
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key = 0;
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hhd = &hash->buckets[key];
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hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
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if (entry->ip == ip)
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return entry;
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}
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return NULL;
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}
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static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
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{
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struct ftrace_func_entry *entry;
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struct hlist_head *hhd;
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unsigned long key;
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entry = kmalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry)
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return -ENOMEM;
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if (hash->size_bits)
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key = hash_long(ip, hash->size_bits);
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else
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key = 0;
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entry->ip = ip;
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hhd = &hash->buckets[key];
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hlist_add_head(&entry->hlist, hhd);
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hash->count++;
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return 0;
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}
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static void
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remove_hash_entry(struct ftrace_hash *hash,
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struct ftrace_func_entry *entry)
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{
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hlist_del(&entry->hlist);
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kfree(entry);
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hash->count--;
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}
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static void ftrace_hash_clear(struct ftrace_hash *hash)
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{
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struct hlist_head *hhd;
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struct hlist_node *tp, *tn;
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struct ftrace_func_entry *entry;
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int size = 1 << hash->size_bits;
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int i;
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for (i = 0; i < size; i++) {
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hhd = &hash->buckets[i];
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hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
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remove_hash_entry(hash, entry);
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}
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FTRACE_WARN_ON(hash->count);
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}
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/*
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* This is a double for. Do not use 'break' to break out of the loop,
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* you must use a goto.
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@ -1032,7 +1122,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
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* If we want to enable it and filtering is on, enable it only if
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* it's filtered
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*/
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if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
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if (enable && !ftrace_lookup_ip(¬race_hash, rec->ip)) {
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if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
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flag = FTRACE_FL_ENABLED;
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}
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@ -1465,7 +1555,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
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!(rec->flags & FTRACE_FL_FILTER)) ||
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((iter->flags & FTRACE_ITER_NOTRACE) &&
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!(rec->flags & FTRACE_FL_NOTRACE))) {
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!ftrace_lookup_ip(¬race_hash, rec->ip))) {
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rec = NULL;
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goto retry;
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}
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@ -1609,14 +1699,15 @@ static void ftrace_filter_reset(int enable)
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{
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struct ftrace_page *pg;
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struct dyn_ftrace *rec;
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unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
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mutex_lock(&ftrace_lock);
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if (enable)
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if (enable) {
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ftrace_filtered = 0;
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do_for_each_ftrace_rec(pg, rec) {
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rec->flags &= ~type;
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} while_for_each_ftrace_rec();
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do_for_each_ftrace_rec(pg, rec) {
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rec->flags &= ~FTRACE_FL_FILTER;
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} while_for_each_ftrace_rec();
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} else
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ftrace_hash_clear(¬race_hash);
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mutex_unlock(&ftrace_lock);
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}
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@ -1716,13 +1807,36 @@ static int ftrace_match(char *str, char *regex, int len, int type)
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return matched;
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}
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static void
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update_record(struct dyn_ftrace *rec, unsigned long flag, int not)
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static int
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update_record(struct dyn_ftrace *rec, int enable, int not)
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{
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if (not)
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rec->flags &= ~flag;
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else
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rec->flags |= flag;
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struct ftrace_func_entry *entry;
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struct ftrace_hash *hash = ¬race_hash;
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int ret = 0;
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if (enable) {
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if (not)
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rec->flags &= ~FTRACE_FL_FILTER;
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else
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rec->flags |= FTRACE_FL_FILTER;
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} else {
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if (not) {
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/* Do nothing if it doesn't exist */
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entry = ftrace_lookup_ip(hash, rec->ip);
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if (!entry)
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return 0;
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remove_hash_entry(hash, entry);
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} else {
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/* Do nothing if it exists */
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entry = ftrace_lookup_ip(hash, rec->ip);
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if (entry)
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return 0;
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ret = add_hash_entry(hash, rec->ip);
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}
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}
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return ret;
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}
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static int
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@ -1754,16 +1868,14 @@ static int match_records(char *buff, int len, char *mod, int enable, int not)
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struct dyn_ftrace *rec;
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int type = MATCH_FULL;
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char *search = buff;
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unsigned long flag;
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int found = 0;
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int ret;
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if (len) {
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type = filter_parse_regex(buff, len, &search, ¬);
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search_len = strlen(search);
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}
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flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
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mutex_lock(&ftrace_lock);
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if (unlikely(ftrace_disabled))
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@ -1772,7 +1884,11 @@ static int match_records(char *buff, int len, char *mod, int enable, int not)
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do_for_each_ftrace_rec(pg, rec) {
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if (ftrace_match_record(rec, mod, search, search_len, type)) {
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update_record(rec, flag, not);
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ret = update_record(rec, enable, not);
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if (ret < 0) {
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found = ret;
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goto out_unlock;
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}
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found = 1;
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}
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/*
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@ -1821,6 +1937,7 @@ static int
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ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
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{
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char *mod;
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int ret = -EINVAL;
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/*
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* cmd == 'mod' because we only registered this func
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@ -1832,15 +1949,19 @@ ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
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/* we must have a module name */
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if (!param)
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return -EINVAL;
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return ret;
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mod = strsep(¶m, ":");
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if (!strlen(mod))
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return -EINVAL;
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return ret;
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if (ftrace_match_module_records(func, mod, enable))
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return 0;
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return -EINVAL;
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ret = ftrace_match_module_records(func, mod, enable);
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if (!ret)
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ret = -EINVAL;
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if (ret < 0)
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return ret;
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return 0;
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}
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static struct ftrace_func_command ftrace_mod_cmd = {
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@ -2132,14 +2253,17 @@ static int ftrace_process_regex(char *buff, int len, int enable)
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{
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char *func, *command, *next = buff;
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struct ftrace_func_command *p;
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int ret = -EINVAL;
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int ret;
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func = strsep(&next, ":");
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if (!next) {
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if (ftrace_match_records(func, len, enable))
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return 0;
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return ret;
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ret = ftrace_match_records(func, len, enable);
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if (!ret)
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ret = -EINVAL;
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if (ret < 0)
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return ret;
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return 0;
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}
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/* command found */
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