Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...

[net-next-2.6.git] / kernel / trace / ftrace.c

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 20aff3f1c71993eaa1c8ec10eaa47479ea179877..65fb077ea79c147c21d6a8a4890a2ec6d17712bc 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1358,24 +1358,29 @@ enum {
 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 
 struct ftrace_iterator {
-       struct ftrace_page      *pg;
-       int                     hidx;
-       int                     idx;
-       unsigned                flags;
-       struct trace_parser     parser;
+       loff_t                          pos;
+       loff_t                          func_pos;
+       struct ftrace_page              *pg;
+       struct dyn_ftrace               *func;
+       struct ftrace_func_probe        *probe;
+       struct trace_parser             parser;
+       int                             hidx;
+       int                             idx;
+       unsigned                        flags;
 };
 
 static void *
-t_hash_next(struct seq_file *m, void *v, loff_t *pos)
+t_hash_next(struct seq_file *m, loff_t *pos)
 {
        struct ftrace_iterator *iter = m->private;
-       struct hlist_node *hnd = v;
+       struct hlist_node *hnd = NULL;
        struct hlist_head *hhd;
 
-       WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
-
        (*pos)++;
+       iter->pos = *pos;
 
+       if (iter->probe)
+               hnd = &iter->probe->node;
  retry:
        if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
                return NULL;
@@ -1398,7 +1403,12 @@ t_hash_next(struct seq_file *m, void *v, loff_t *pos)
                }
        }
 
-       return hnd;
+       if (WARN_ON_ONCE(!hnd))
+               return NULL;
+
+       iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
+
+       return iter;
 }
 
 static void *t_hash_start(struct seq_file *m, loff_t *pos)
@@ -1407,26 +1417,32 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos)
        void *p = NULL;
        loff_t l;
 
-       if (!(iter->flags & FTRACE_ITER_HASH))
-               *pos = 0;
-
-       iter->flags |= FTRACE_ITER_HASH;
+       if (iter->func_pos > *pos)
+               return NULL;
 
        iter->hidx = 0;
-       for (l = 0; l <= *pos; ) {
-               p = t_hash_next(m, p, &l);
+       for (l = 0; l <= (*pos - iter->func_pos); ) {
+               p = t_hash_next(m, &l);
                if (!p)
                        break;
        }
-       return p;
+       if (!p)
+               return NULL;
+
+       /* Only set this if we have an item */
+       iter->flags |= FTRACE_ITER_HASH;
+
+       return iter;
 }
 
-static int t_hash_show(struct seq_file *m, void *v)
+static int
+t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
 {
        struct ftrace_func_probe *rec;
-       struct hlist_node *hnd = v;
 
-       rec = hlist_entry(hnd, struct ftrace_func_probe, node);
+       rec = iter->probe;
+       if (WARN_ON_ONCE(!rec))
+               return -EIO;
 
        if (rec->ops->print)
                return rec->ops->print(m, rec->ip, rec->ops, rec->data);
@@ -1447,12 +1463,13 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
        struct dyn_ftrace *rec = NULL;
 
        if (iter->flags & FTRACE_ITER_HASH)
-               return t_hash_next(m, v, pos);
+               return t_hash_next(m, pos);
 
        (*pos)++;
+       iter->pos = *pos;
 
        if (iter->flags & FTRACE_ITER_PRINTALL)
-               return NULL;
+               return t_hash_start(m, pos);
 
  retry:
        if (iter->idx >= iter->pg->index) {
@@ -1481,7 +1498,20 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
                }
        }
 
-       return rec;
+       if (!rec)
+               return t_hash_start(m, pos);
+
+       iter->func_pos = *pos;
+       iter->func = rec;
+
+       return iter;
+}
+
+static void reset_iter_read(struct ftrace_iterator *iter)
+{
+       iter->pos = 0;
+       iter->func_pos = 0;
+       iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
@@ -1491,6 +1521,12 @@ static void *t_start(struct seq_file *m, loff_t *pos)
        loff_t l;
 
        mutex_lock(&ftrace_lock);
+       /*
+        * If an lseek was done, then reset and start from beginning.
+        */
+       if (*pos < iter->pos)
+               reset_iter_read(iter);
+
        /*
         * For set_ftrace_filter reading, if we have the filter
         * off, we can short cut and just print out that all
@@ -1500,12 +1536,19 @@ static void *t_start(struct seq_file *m, loff_t *pos)
                if (*pos > 0)
                        return t_hash_start(m, pos);
                iter->flags |= FTRACE_ITER_PRINTALL;
+               /* reset in case of seek/pread */
+               iter->flags &= ~FTRACE_ITER_HASH;
                return iter;
        }
 
        if (iter->flags & FTRACE_ITER_HASH)
                return t_hash_start(m, pos);
 
+       /*
+        * Unfortunately, we need to restart at ftrace_pages_start
+        * every time we let go of the ftrace_mutex. This is because
+        * those pointers can change without the lock.
+        */
        iter->pg = ftrace_pages_start;
        iter->idx = 0;
        for (l = 0; l <= *pos; ) {
@@ -1514,10 +1557,14 @@ static void *t_start(struct seq_file *m, loff_t *pos)
                        break;
        }
 
-       if (!p && iter->flags & FTRACE_ITER_FILTER)
-               return t_hash_start(m, pos);
+       if (!p) {
+               if (iter->flags & FTRACE_ITER_FILTER)
+                       return t_hash_start(m, pos);
 
-       return p;
+               return NULL;
+       }
+
+       return iter;
 }
 
 static void t_stop(struct seq_file *m, void *p)
@@ -1528,16 +1575,18 @@ static void t_stop(struct seq_file *m, void *p)
 static int t_show(struct seq_file *m, void *v)
 {
        struct ftrace_iterator *iter = m->private;
-       struct dyn_ftrace *rec = v;
+       struct dyn_ftrace *rec;
 
        if (iter->flags & FTRACE_ITER_HASH)
-               return t_hash_show(m, v);
+               return t_hash_show(m, iter);
 
        if (iter->flags & FTRACE_ITER_PRINTALL) {
                seq_printf(m, "#### all functions enabled ####\n");
                return 0;
        }
 
+       rec = iter->func;
+
        if (!rec)
                return 0;
 
@@ -2406,7 +2455,7 @@ static const struct file_operations ftrace_filter_fops = {
        .open = ftrace_filter_open,
        .read = seq_read,
        .write = ftrace_filter_write,
-       .llseek = no_llseek,
+       .llseek = ftrace_regex_lseek,
        .release = ftrace_filter_release,
 };