ftrace: Remove FTRACE_FL_FAILED flag

Since we disable all function tracer processing if we detect
that a modification of a instruction had failed, we do not need
to track that the record has failed. No more ftrace processing
is allowed, and the FTRACE_FL_FAILED flag is pointless.

Removing this flag simplifies some of the code, but some ftrace_disabled
checks needed to be added or move around a little.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index ca29e03..2a195ff 100644 (file)
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -147,11 +147,10 @@ extern int ftrace_text_reserved(void *start, void *end);
 
 enum {
        FTRACE_FL_FREE          = (1 << 0),
-       FTRACE_FL_FAILED        = (1 << 1),
-       FTRACE_FL_FILTER        = (1 << 2),
-       FTRACE_FL_ENABLED       = (1 << 3),
-       FTRACE_FL_NOTRACE       = (1 << 4),
-       FTRACE_FL_CONVERTED     = (1 << 5),
+       FTRACE_FL_FILTER        = (1 << 1),
+       FTRACE_FL_ENABLED       = (1 << 2),
+       FTRACE_FL_NOTRACE       = (1 << 3),
+       FTRACE_FL_CONVERTED     = (1 << 4),
 };
 
 struct dyn_ftrace {

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 97b30f8..eb19fae 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1083,19 +1083,20 @@ static void ftrace_replace_code(int enable)
        struct ftrace_page *pg;
        int failed;
 
+       if (unlikely(ftrace_disabled))
+               return;
+
        do_for_each_ftrace_rec(pg, rec) {
                /*
                 * Skip over free records, records that have
                 * failed and not converted.
                 */
                if (rec->flags & FTRACE_FL_FREE ||
-                   rec->flags & FTRACE_FL_FAILED ||
                    !(rec->flags & FTRACE_FL_CONVERTED))
                        continue;
 
                failed = __ftrace_replace_code(rec, enable);
                if (failed) {
-                       rec->flags |= FTRACE_FL_FAILED;
                        ftrace_bug(failed, rec->ip);
                        /* Stop processing */
                        return;
@@ -1111,10 +1112,12 @@ ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 
        ip = rec->ip;
 
+       if (unlikely(ftrace_disabled))
+               return 0;
+
        ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
        if (ret) {
                ftrace_bug(ret, ip);
-               rec->flags |= FTRACE_FL_FAILED;
                return 0;
        }
        return 1;
@@ -1466,6 +1469,9 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
        struct ftrace_iterator *iter = m->private;
        struct dyn_ftrace *rec = NULL;
 
+       if (unlikely(ftrace_disabled))
+               return NULL;
+
        if (iter->flags & FTRACE_ITER_HASH)
                return t_hash_next(m, pos);
 
@@ -1518,6 +1524,10 @@ static void *t_start(struct seq_file *m, loff_t *pos)
        loff_t l;
 
        mutex_lock(&ftrace_lock);
+
+       if (unlikely(ftrace_disabled))
+               return NULL;
+
        /*
         * If an lseek was done, then reset and start from beginning.
         */
@@ -1636,8 +1646,6 @@ static void ftrace_filter_reset(int enable)
        if (enable)
                ftrace_filtered = 0;
        do_for_each_ftrace_rec(pg, rec) {
-               if (rec->flags & FTRACE_FL_FAILED)
-                       continue;
                rec->flags &= ~type;
        } while_for_each_ftrace_rec();
        mutex_unlock(&ftrace_lock);
@@ -1767,9 +1775,6 @@ static int ftrace_match_records(char *buff, int len, int enable)
        mutex_lock(&ftrace_lock);
        do_for_each_ftrace_rec(pg, rec) {
 
-               if (rec->flags & FTRACE_FL_FAILED)
-                       continue;
-
                if (ftrace_match_record(rec, search, search_len, type)) {
                        if (not)
                                rec->flags &= ~flag;
@@ -1837,10 +1842,11 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable)
        }
 
        mutex_lock(&ftrace_lock);
-       do_for_each_ftrace_rec(pg, rec) {
 
-               if (rec->flags & FTRACE_FL_FAILED)
-                       continue;
+       if (unlikely(ftrace_disabled))
+               goto out_unlock;
+
+       do_for_each_ftrace_rec(pg, rec) {
 
                if (ftrace_match_module_record(rec, mod,
                                               search, search_len, type)) {
@@ -1854,6 +1860,7 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable)
                        ftrace_filtered = 1;
 
        } while_for_each_ftrace_rec();
+ out_unlock:
        mutex_unlock(&ftrace_lock);
 
        return found;
@@ -2008,10 +2015,11 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
                return -EINVAL;
 
        mutex_lock(&ftrace_lock);
-       do_for_each_ftrace_rec(pg, rec) {
 
-               if (rec->flags & FTRACE_FL_FAILED)
-                       continue;
+       if (unlikely(ftrace_disabled))
+               goto out_unlock;
+
+       do_for_each_ftrace_rec(pg, rec) {
 
                if (!ftrace_match_record(rec, search, len, type))
                        continue;
@@ -2218,6 +2226,10 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 
        mutex_lock(&ftrace_regex_lock);
 
+       ret = -ENODEV;
+       if (unlikely(ftrace_disabled))
+               goto out_unlock;
+
        if (file->f_mode & FMODE_READ) {
                struct seq_file *m = file->private_data;
                iter = m->private;
@@ -2545,9 +2557,6 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
        bool exists;
        int i;
 
-       if (ftrace_disabled)
-               return -ENODEV;
-
        /* decode regex */
        type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
        if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
@@ -2556,9 +2565,15 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
        search_len = strlen(search);
 
        mutex_lock(&ftrace_lock);
+
+       if (unlikely(ftrace_disabled)) {
+               mutex_unlock(&ftrace_lock);
+               return -ENODEV;
+       }
+
        do_for_each_ftrace_rec(pg, rec) {
 
-               if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
+               if (rec->flags & FTRACE_FL_FREE)
                        continue;
 
                if (ftrace_match_record(rec, search, search_len, type)) {
@@ -2700,10 +2715,11 @@ void ftrace_release_mod(struct module *mod)
        struct dyn_ftrace *rec;
        struct ftrace_page *pg;
 
+       mutex_lock(&ftrace_lock);
+
        if (ftrace_disabled)
-               return;
+               goto out_unlock;
 
-       mutex_lock(&ftrace_lock);
        do_for_each_ftrace_rec(pg, rec) {
                if (within_module_core(rec->ip, mod)) {
                        /*
@@ -2714,6 +2730,7 @@ void ftrace_release_mod(struct module *mod)
                        ftrace_free_rec(rec);
                }
        } while_for_each_ftrace_rec();
+ out_unlock:
        mutex_unlock(&ftrace_lock);
 }
 
@@ -3108,16 +3125,17 @@ void ftrace_kill(void)
  */
 int register_ftrace_function(struct ftrace_ops *ops)
 {
-       int ret;
-
-       if (unlikely(ftrace_disabled))
-               return -1;
+       int ret = -1;
 
        mutex_lock(&ftrace_lock);
 
+       if (unlikely(ftrace_disabled))
+               goto out_unlock;
+
        ret = __register_ftrace_function(ops);
        ftrace_startup(0);
 
+ out_unlock:
        mutex_unlock(&ftrace_lock);
        return ret;
 }
@@ -3145,14 +3163,14 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
                     void __user *buffer, size_t *lenp,
                     loff_t *ppos)
 {
-       int ret;
-
-       if (unlikely(ftrace_disabled))
-               return -ENODEV;
+       int ret = -ENODEV;
 
        mutex_lock(&ftrace_lock);
 
-       ret  = proc_dointvec(table, write, buffer, lenp, ppos);
+       if (unlikely(ftrace_disabled))
+               goto out;
+
+       ret = proc_dointvec(table, write, buffer, lenp, ppos);
 
        if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
                goto out;