tracing: move tgid out of generic entry and into userstack

[safe/jmp/linux-2.6] / kernel / trace / trace_output.c

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index c12d95d..be34a6a 100644 (file)
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -14,9 +14,10 @@
 /* must be a power of 2 */
 #define EVENT_HASHSIZE 128
 
-static DECLARE_RWSEM(trace_event_mutex);
+DECLARE_RWSEM(trace_event_mutex);
 
 DEFINE_PER_CPU(struct trace_seq, ftrace_event_seq);
+EXPORT_PER_CPU_SYMBOL(ftrace_event_seq);
 
 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
 
@@ -26,8 +27,7 @@ void trace_print_seq(struct seq_file *m, struct trace_seq *s)
 {
        int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
 
-       s->buffer[len] = 0;
-       seq_puts(m, s->buffer);
+       seq_write(m, s->buffer, len);
 
        trace_seq_init(s);
 }
@@ -99,6 +99,38 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 }
 EXPORT_SYMBOL_GPL(trace_seq_printf);
 
+/**
+ * trace_seq_vprintf - sequence printing of trace information
+ * @s: trace sequence descriptor
+ * @fmt: printf format string
+ *
+ * The tracer may use either sequence operations or its own
+ * copy to user routines. To simplify formating of a trace
+ * trace_seq_printf is used to store strings into a special
+ * buffer (@s). Then the output may be either used by
+ * the sequencer or pulled into another buffer.
+ */
+int
+trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+{
+       int len = (PAGE_SIZE - 1) - s->len;
+       int ret;
+
+       if (!len)
+               return 0;
+
+       ret = vsnprintf(s->buffer + s->len, len, fmt, args);
+
+       /* If we can't write it all, don't bother writing anything */
+       if (ret >= len)
+               return 0;
+
+       s->len += ret;
+
+       return len;
+}
+EXPORT_SYMBOL_GPL(trace_seq_vprintf);
+
 int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
        int len = (PAGE_SIZE - 1) - s->len;
@@ -222,10 +254,9 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
 {
        unsigned long mask;
        const char *str;
+       const char *ret = p->buffer + p->len;
        int i;
 
-       trace_seq_init(p);
-
        for (i = 0;  flag_array[i].name && flags; i++) {
 
                mask = flag_array[i].mask;
@@ -248,16 +279,16 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
 
        trace_seq_putc(p, 0);
 
-       return p->buffer;
+       return ret;
 }
+EXPORT_SYMBOL(ftrace_print_flags_seq);
 
 const char *
 ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
                         const struct trace_print_flags *symbol_array)
 {
        int i;
-
-       trace_seq_init(p);
+       const char *ret = p->buffer + p->len;
 
        for (i = 0;  symbol_array[i].name; i++) {
 
@@ -273,8 +304,9 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
                
        trace_seq_putc(p, 0);
 
-       return p->buffer;
+       return ret;
 }
+EXPORT_SYMBOL(ftrace_print_symbols_seq);
 
 #ifdef CONFIG_KRETPROBES
 static inline const char *kretprobed(const char *name)
@@ -375,7 +407,7 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
                 * since individual threads might have already quit!
                 */
                rcu_read_lock();
-               task = find_task_by_vpid(entry->ent.tgid);
+               task = find_task_by_vpid(entry->tgid);
                if (task)
                        mm = get_task_mm(task);
                rcu_read_unlock();
@@ -386,17 +418,20 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 
                if (ip == ULONG_MAX || !ret)
                        break;
-               if (i && ret)
-                       ret = trace_seq_puts(s, " <- ");
+               if (ret)
+                       ret = trace_seq_puts(s, " => ");
                if (!ip) {
                        if (ret)
                                ret = trace_seq_puts(s, "??");
+                       if (ret)
+                               ret = trace_seq_puts(s, "\n");
                        continue;
                }
                if (!ret)
                        break;
                if (ret)
                        ret = seq_print_user_ip(s, mm, ip, sym_flags);
+               ret = trace_seq_puts(s, "\n");
        }
 
        if (mm)
@@ -666,6 +701,16 @@ int register_ftrace_event(struct trace_event *event)
 }
 EXPORT_SYMBOL_GPL(register_ftrace_event);
 
+/*
+ * Used by module code with the trace_event_mutex held for write.
+ */
+int __unregister_ftrace_event(struct trace_event *event)
+{
+       hlist_del(&event->node);
+       list_del(&event->list);
+       return 0;
+}
+
 /**
  * unregister_ftrace_event - remove a no longer used event
  * @event: the event to remove
@@ -673,8 +718,7 @@ EXPORT_SYMBOL_GPL(register_ftrace_event);
 int unregister_ftrace_event(struct trace_event *event)
 {
        down_write(&trace_event_mutex);
-       hlist_del(&event->node);
-       list_del(&event->list);
+       __unregister_ftrace_event(event);
        up_write(&trace_event_mutex);
 
        return 0;
@@ -972,16 +1016,16 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
 
        trace_assign_type(field, iter->ent);
 
+       if (!trace_seq_puts(s, "<stack trace>\n"))
+               goto partial;
        for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
-               if (!field->caller[i])
+               if (!field->caller[i] || (field->caller[i] == ULONG_MAX))
                        break;
-               if (i) {
-                       if (!trace_seq_puts(s, " <= "))
-                               goto partial;
+               if (!trace_seq_puts(s, " => "))
+                       goto partial;
 
-                       if (!seq_print_ip_sym(s, field->caller[i], flags))
-                               goto partial;
-               }
+               if (!seq_print_ip_sym(s, field->caller[i], flags))
+                       goto partial;
                if (!trace_seq_puts(s, "\n"))
                        goto partial;
        }
@@ -1009,10 +1053,10 @@ static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
 
        trace_assign_type(field, iter->ent);
 
-       if (!seq_print_userip_objs(field, s, flags))
+       if (!trace_seq_puts(s, "<user stack trace>\n"))
                goto partial;
 
-       if (!trace_seq_putc(s, '\n'))
+       if (!seq_print_userip_objs(field, s, flags))
                goto partial;
 
        return TRACE_TYPE_HANDLED;