14 files changed, 133 insertions, 172 deletions

diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt
index 2041ee951c1a..22614bef6359 100644
--- a/Documentation/ftrace.txt
+++ b/Documentation/ftrace.txt
@@ -1466,11 +1466,11 @@ want, depending on your needs.
 
 
 You can put some comments on specific functions by using
-ftrace_printk() For example, if you want to put a comment inside
+trace_printk() For example, if you want to put a comment inside
 the __might_sleep() function, you just have to include
-<linux/ftrace.h> and call ftrace_printk() inside __might_sleep()
+<linux/ftrace.h> and call trace_printk() inside __might_sleep()
 
-ftrace_printk("I'm a comment!\n")
+trace_printk("I'm a comment!\n")
 
 will produce:
 
diff --git a/arch/Kconfig b/arch/Kconfig
index 550dab22daa1..a092dc77c24d 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -6,6 +6,7 @@ config OPROFILE
         tristate "OProfile system profiling (EXPERIMENTAL)"
         depends on PROFILING
         depends on HAVE_OPROFILE
+        depends on TRACING_SUPPORT
         select TRACING
         select RING_BUFFER
         help
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 6ea62acbe4b6..498769425eb2 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -319,62 +319,6 @@ static inline void __ftrace_enabled_restore(int enabled)
 # define trace_preempt_off(a0, a1)              do { } while (0)
 #endif
 
-#ifdef CONFIG_TRACING
-extern int ftrace_dump_on_oops;
-
-extern void tracing_start(void);
-extern void tracing_stop(void);
-extern void ftrace_off_permanent(void);
-
-extern void
-ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
-
-/**
- * ftrace_printk - printf formatting in the ftrace buffer
- * @fmt: the printf format for printing
- *
- * Note: __ftrace_printk is an internal function for ftrace_printk and
- *       the @ip is passed in via the ftrace_printk macro.
- *
- * This function allows a kernel developer to debug fast path sections
- * that printk is not appropriate for. By scattering in various
- * printk like tracing in the code, a developer can quickly see
- * where problems are occurring.
- *
- * This is intended as a debugging tool for the developer only.
- * Please refrain from leaving ftrace_printks scattered around in
- * your code.
- */
-# define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
-extern int
-__ftrace_printk(unsigned long ip, const char *fmt, ...)
-        __attribute__ ((format (printf, 2, 3)));
-# define ftrace_vprintk(fmt, ap) __ftrace_printk(_THIS_IP_, fmt, ap)
-extern int
-__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
-extern void ftrace_dump(void);
-#else
-static inline void
-ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
-static inline int
-ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
-
-static inline void tracing_start(void) { }
-static inline void tracing_stop(void) { }
-static inline void ftrace_off_permanent(void) { }
-static inline int
-ftrace_printk(const char *fmt, ...)
-{
-        return 0;
-}
-static inline int
-ftrace_vprintk(const char *fmt, va_list ap)
-{
-        return 0;
-}
-static inline void ftrace_dump(void) { }
-#endif
-
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 extern void ftrace_init(void);
 extern void ftrace_init_module(struct module *mod,
@@ -543,6 +487,8 @@ static inline int test_tsk_trace_graph(struct task_struct *tsk)
         return tsk->trace & TSK_TRACE_FL_GRAPH;
 }
 
+extern int ftrace_dump_on_oops;
+
 #endif /* CONFIG_TRACING */
 
 
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 7fa371898e3e..08bf5da86676 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -368,6 +368,64 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
 #endif
 
 /*
+ * General tracing related utility functions - trace_printk(),
+ * tracing_start()/tracing_stop:
+ */
+#ifdef CONFIG_TRACING
+extern void tracing_start(void);
+extern void tracing_stop(void);
+extern void ftrace_off_permanent(void);
+
+extern void
+ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
+
+/**
+ * trace_printk - printf formatting in the ftrace buffer
+ * @fmt: the printf format for printing
+ *
+ * Note: __trace_printk is an internal function for trace_printk and
+ *       the @ip is passed in via the trace_printk macro.
+ *
+ * This function allows a kernel developer to debug fast path sections
+ * that printk is not appropriate for. By scattering in various
+ * printk like tracing in the code, a developer can quickly see
+ * where problems are occurring.
+ *
+ * This is intended as a debugging tool for the developer only.
+ * Please refrain from leaving trace_printks scattered around in
+ * your code.
+ */
+# define trace_printk(fmt...) __trace_printk(_THIS_IP_, fmt)
+extern int
+__trace_printk(unsigned long ip, const char *fmt, ...)
+        __attribute__ ((format (printf, 2, 3)));
+# define ftrace_vprintk(fmt, ap) __trace_printk(_THIS_IP_, fmt, ap)
+extern int
+__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
+extern void ftrace_dump(void);
+#else
+static inline void
+ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
+static inline int
+trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
+
+static inline void tracing_start(void) { }
+static inline void tracing_stop(void) { }
+static inline void ftrace_off_permanent(void) { }
+static inline int
+trace_printk(const char *fmt, ...)
+{
+        return 0;
+}
+static inline int
+ftrace_vprintk(const char *fmt, va_list ap)
+{
+        return 0;
+}
+static inline void ftrace_dump(void) { }
+#endif
+
+/*
  *      Display an IP address in readable format.
  */
 
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 999c6a2485df..5d733da5345a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -53,12 +53,22 @@ config TRACING
         select TRACEPOINTS
         select NOP_TRACER
 
+#
+# Minimum requirements an architecture has to meet for us to
+# be able to offer generic tracing facilities:
+#
+config TRACING_SUPPORT
+        bool
+        depends on TRACE_IRQFLAGS_SUPPORT
+        depends on STACKTRACE_SUPPORT
+
+if TRACING_SUPPORT
+
 menu "Tracers"
 
 config FUNCTION_TRACER
         bool "Kernel Function Tracer"
         depends on HAVE_FUNCTION_TRACER
-        depends on DEBUG_KERNEL
         select FRAME_POINTER
         select KALLSYMS
         select TRACING
@@ -91,7 +101,6 @@ config IRQSOFF_TRACER
         default n
         depends on TRACE_IRQFLAGS_SUPPORT
         depends on GENERIC_TIME
-        depends on DEBUG_KERNEL
         select TRACE_IRQFLAGS
         select TRACING
         select TRACER_MAX_TRACE
@@ -114,7 +123,6 @@ config PREEMPT_TRACER
         default n
         depends on GENERIC_TIME
         depends on PREEMPT
-        depends on DEBUG_KERNEL
         select TRACING
         select TRACER_MAX_TRACE
         help
@@ -142,7 +150,6 @@ config SYSPROF_TRACER
 
 config SCHED_TRACER
         bool "Scheduling Latency Tracer"
-        depends on DEBUG_KERNEL
         select TRACING
         select CONTEXT_SWITCH_TRACER
         select TRACER_MAX_TRACE
@@ -152,7 +159,6 @@ config SCHED_TRACER
 
 config CONTEXT_SWITCH_TRACER
         bool "Trace process context switches"
-        depends on DEBUG_KERNEL
         select TRACING
         select MARKERS
         help
@@ -161,7 +167,6 @@ config CONTEXT_SWITCH_TRACER
 
 config EVENT_TRACER
         bool "Trace various events in the kernel"
-        depends on DEBUG_KERNEL
         select TRACING
         help
           This tracer hooks to various trace points in the kernel
@@ -170,7 +175,6 @@ config EVENT_TRACER
 
 config BOOT_TRACER
         bool "Trace boot initcalls"
-        depends on DEBUG_KERNEL
         select TRACING
         select CONTEXT_SWITCH_TRACER
         help
@@ -188,7 +192,6 @@ config BOOT_TRACER
 
 config TRACE_BRANCH_PROFILING
         bool "Trace likely/unlikely profiler"
-        depends on DEBUG_KERNEL
         select TRACING
         help
           This tracer profiles all the the likely and unlikely macros
@@ -241,7 +244,6 @@ config BRANCH_TRACER
 
 config POWER_TRACER
         bool "Trace power consumption behavior"
-        depends on DEBUG_KERNEL
         depends on X86
         select TRACING
         help
@@ -253,7 +255,6 @@ config POWER_TRACER
 config STACK_TRACER
         bool "Trace max stack"
         depends on HAVE_FUNCTION_TRACER
-        depends on DEBUG_KERNEL
         select FUNCTION_TRACER
         select STACKTRACE
         select KALLSYMS
@@ -343,7 +344,6 @@ config DYNAMIC_FTRACE
         bool "enable/disable ftrace tracepoints dynamically"
         depends on FUNCTION_TRACER
         depends on HAVE_DYNAMIC_FTRACE
-        depends on DEBUG_KERNEL
         default y
         help
          This option will modify all the calls to ftrace dynamically
@@ -369,7 +369,7 @@ config FTRACE_SELFTEST
 
 config FTRACE_STARTUP_TEST
         bool "Perform a startup test on ftrace"
-        depends on TRACING && DEBUG_KERNEL
+        depends on TRACING
         select FTRACE_SELFTEST
         help
           This option performs a series of startup tests on ftrace. On bootup
@@ -379,7 +379,7 @@ config FTRACE_STARTUP_TEST
 
 config MMIOTRACE
         bool "Memory mapped IO tracing"
-        depends on HAVE_MMIOTRACE_SUPPORT && DEBUG_KERNEL && PCI
+        depends on HAVE_MMIOTRACE_SUPPORT && PCI
         select TRACING
         help
           Mmiotrace traces Memory Mapped I/O access and is meant for
@@ -401,3 +401,6 @@ config MMIOTRACE_TEST
           Say N, unless you absolutely know what you are doing.
 
 endmenu
+
+endif # TRACING_SUPPORT
+
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index e82cb9e930cc..e39679a72a3b 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1231,7 +1231,6 @@ static struct tracer blk_tracer __read_mostly = {
 static struct trace_event trace_blk_event = {
         .type           = TRACE_BLK,
         .trace          = blk_trace_event_print,
-        .latency_trace  = blk_trace_event_print,
         .binary         = blk_trace_event_print_binary,
 };
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f2a163db52f9..f7473645b9c6 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2461,6 +2461,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
         unsigned long flags;
         unsigned int commit;
         unsigned int read;
+        u64 save_timestamp;
         int ret = -1;
 
         /*
@@ -2515,6 +2516,9 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
                 if (len < size)
                         goto out;
 
+                /* save the current timestamp, since the user will need it */
+                save_timestamp = cpu_buffer->read_stamp;
+
                 /* Need to copy one event at a time */
                 do {
                         memcpy(bpage->data + pos, rpage->data + rpos, size);
@@ -2531,7 +2535,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
 
                 /* update bpage */
                 local_set(&bpage->commit, pos);
-                bpage->time_stamp = rpage->time_stamp;
+                bpage->time_stamp = save_timestamp;
 
                 /* we copied everything to the beginning */
                 read = 0;
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c8abbb0c8397..c0e9c1263393 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -48,7 +48,7 @@ unsigned long __read_mostly	tracing_thresh;
  * We need to change this state when a selftest is running.
  * A selftest will lurk into the ring-buffer to count the
  * entries inserted during the selftest although some concurrent
- * insertions into the ring-buffer such as ftrace_printk could occurred
+ * insertions into the ring-buffer such as trace_printk could occurred
  * at the same time, giving false positive or negative results.
  */
 static bool __read_mostly tracing_selftest_running;
@@ -291,7 +291,7 @@ static const char *trace_options[] = {
         "block",
         "stacktrace",
         "sched-tree",
-        "ftrace_printk",
+        "trace_printk",
         "ftrace_preempt",
         "branch",
         "annotate",
@@ -299,6 +299,7 @@ static const char *trace_options[] = {
         "sym-userobj",
         "printk-msg-only",
         "context-info",
+        "latency-format",
         NULL
 };
 
@@ -346,6 +347,9 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
         int len;
         int ret;
 
+        if (!cnt)
+                return 0;
+
         if (s->len <= s->readpos)
                 return -EBUSY;
 
@@ -353,10 +357,12 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
         if (cnt > len)
                 cnt = len;
         ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
-        if (ret)
+        if (ret == cnt)
                 return -EFAULT;
 
-        s->readpos += len;
+        cnt -= ret;
+
+        s->readpos += cnt;
         return cnt;
 }
 
@@ -375,7 +381,7 @@ ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
         if (!ret)
                 return -EFAULT;
 
-        s->readpos += len;
+        s->readpos += cnt;
         return cnt;
 }
 
@@ -1462,33 +1468,6 @@ static void test_cpu_buff_start(struct trace_iterator *iter)
         trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
 }
 
-static enum print_line_t print_lat_fmt(struct trace_iterator *iter)
-{
-        struct trace_seq *s = &iter->seq;
-        unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
-        struct trace_event *event;
-        struct trace_entry *entry = iter->ent;
-
-        test_cpu_buff_start(iter);
-
-        event = ftrace_find_event(entry->type);
-
-        if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-                if (!trace_print_lat_context(iter))
-                        goto partial;
-        }
-
-        if (event)
-                return event->latency_trace(iter, sym_flags);
-
-        if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
-                goto partial;
-
-        return TRACE_TYPE_HANDLED;
-partial:
-        return TRACE_TYPE_PARTIAL_LINE;
-}
-
 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
 {
         struct trace_seq *s = &iter->seq;
@@ -1503,8 +1482,13 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
         event = ftrace_find_event(entry->type);
 
         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-                if (!trace_print_context(iter))
-                        goto partial;
+                if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
+                        if (!trace_print_lat_context(iter))
+                                goto partial;
+                } else {
+                        if (!trace_print_context(iter))
+                                goto partial;
+                }
         }
 
         if (event)
@@ -1646,9 +1630,6 @@ static enum print_line_t print_trace_line(struct trace_iterator *iter)
         if (trace_flags & TRACE_ITER_RAW)
                 return print_raw_fmt(iter);
 
-        if (iter->iter_flags & TRACE_FILE_LAT_FMT)
-                return print_lat_fmt(iter);
-
         return print_trace_fmt(iter);
 }
 
@@ -1824,26 +1805,12 @@ static int tracing_open(struct inode *inode, struct file *file)
         iter = __tracing_open(inode, file);
         if (IS_ERR(iter))
                 ret = PTR_ERR(iter);
-
-        return ret;
-}
-
-static int tracing_lt_open(struct inode *inode, struct file *file)
-{
-        struct trace_iterator *iter;
-        int ret = 0;
-
-        iter = __tracing_open(inode, file);
-
-        if (IS_ERR(iter))
-                ret = PTR_ERR(iter);
-        else
+        else if (trace_flags & TRACE_ITER_LATENCY_FMT)
                 iter->iter_flags |= TRACE_FILE_LAT_FMT;
 
         return ret;
 }
 
-
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
@@ -1922,13 +1889,6 @@ static struct file_operations tracing_fops = {
         .release        = tracing_release,
 };
 
-static struct file_operations tracing_lt_fops = {
-        .open           = tracing_lt_open,
-        .read           = seq_read,
-        .llseek         = seq_lseek,
-        .release        = tracing_release,
-};
-
 static struct file_operations show_traces_fops = {
         .open           = show_traces_open,
         .read           = seq_read,
@@ -3049,6 +3009,9 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
         ssize_t ret;
         size_t size;
 
+        if (!count)
+                return 0;
+
         /* Do we have previous read data to read? */
         if (info->read < PAGE_SIZE)
                 goto read;
@@ -3073,8 +3036,10 @@ read:
                 size = count;
 
         ret = copy_to_user(ubuf, info->spare + info->read, size);
-        if (ret)
+        if (ret == size)
                 return -EFAULT;
+        size -= ret;
+
         *ppos += size;
         info->read += size;
 
@@ -3803,7 +3768,7 @@ int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
 }
 EXPORT_SYMBOL_GPL(trace_vprintk);
 
-int __ftrace_printk(unsigned long ip, const char *fmt, ...)
+int __trace_printk(unsigned long ip, const char *fmt, ...)
 {
         int ret;
         va_list ap;
@@ -3816,7 +3781,7 @@ int __ftrace_printk(unsigned long ip, const char *fmt, ...)
         va_end(ap);
         return ret;
 }
-EXPORT_SYMBOL_GPL(__ftrace_printk);
+EXPORT_SYMBOL_GPL(__trace_printk);
 
 int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
 {
@@ -3918,8 +3883,10 @@ void ftrace_dump(void)
 
         printk(KERN_TRACE "Dumping ftrace buffer:\n");
 
+        /* Simulate the iterator */
         iter.tr = &global_trace;
         iter.trace = current_trace;
+        iter.cpu_file = TRACE_PIPE_ALL_CPU;
 
         /*
          * We need to stop all tracing on all CPUS to read the
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 561bb5c5d988..8beff03fda68 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -115,7 +115,7 @@ struct userstack_entry {
 };
 
 /*
- * ftrace_printk entry:
+ * trace_printk entry:
  */
 struct print_entry {
         struct trace_entry      ent;
@@ -651,7 +651,8 @@ enum trace_iterator_flags {
         TRACE_ITER_USERSTACKTRACE       = 0x4000,
         TRACE_ITER_SYM_USEROBJ          = 0x8000,
         TRACE_ITER_PRINTK_MSGONLY       = 0x10000,
-        TRACE_ITER_CONTEXT_INFO         = 0x20000 /* Print pid/cpu/time */
+        TRACE_ITER_CONTEXT_INFO         = 0x20000, /* Print pid/cpu/time */
+        TRACE_ITER_LATENCY_FMT          = 0x40000,
 };
 
 /*
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index c2e68d440c4d..aaa0755268b9 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -159,7 +159,6 @@ static enum print_line_t trace_branch_print(struct trace_iterator *iter,
 static struct trace_event trace_branch_event = {
         .type           = TRACE_BRANCH,
         .trace          = trace_branch_print,
-        .latency_trace  = trace_branch_print,
 };
 
 static struct tracer branch_trace __read_mostly =
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 9e5ebd844158..b923d13e2fad 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -32,6 +32,8 @@ enum {
 
 static int trace_type __read_mostly;
 
+static int save_lat_flag;
+
 #ifdef CONFIG_PREEMPT_TRACER
 static inline int
 preempt_trace(void)
@@ -370,6 +372,9 @@ static void stop_irqsoff_tracer(struct trace_array *tr)
 
 static void __irqsoff_tracer_init(struct trace_array *tr)
 {
+        save_lat_flag = trace_flags & TRACE_ITER_LATENCY_FMT;
+        trace_flags |= TRACE_ITER_LATENCY_FMT;
+
         tracing_max_latency = 0;
         irqsoff_trace = tr;
         /* make sure that the tracer is visible */
@@ -380,6 +385,9 @@ static void __irqsoff_tracer_init(struct trace_array *tr)
 static void irqsoff_tracer_reset(struct trace_array *tr)
 {
         stop_irqsoff_tracer(tr);
+
+        if (!save_lat_flag)
+                trace_flags &= ~TRACE_ITER_LATENCY_FMT;
 }
 
 static void irqsoff_tracer_start(struct trace_array *tr)
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 9fc815031b09..306fef84c503 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -437,8 +437,6 @@ int register_ftrace_event(struct trace_event *event)
 
         if (event->trace == NULL)
                 event->trace = trace_nop_print;
-        if (event->latency_trace == NULL)
-                event->latency_trace = trace_nop_print;
         if (event->raw == NULL)
                 event->raw = trace_nop_print;
         if (event->hex == NULL)
@@ -480,29 +478,6 @@ enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags)
 }
 
 /* TRACE_FN */
-static enum print_line_t trace_fn_latency(struct trace_iterator *iter,
-                                          int flags)
-{
-        struct ftrace_entry *field;
-        struct trace_seq *s = &iter->seq;
-
-        trace_assign_type(field, iter->ent);
-
-        if (!seq_print_ip_sym(s, field->ip, flags))
-                goto partial;
-        if (!trace_seq_puts(s, " ("))
-                goto partial;
-        if (!seq_print_ip_sym(s, field->parent_ip, flags))
-                goto partial;
-        if (!trace_seq_puts(s, ")\n"))
-                goto partial;
-
-        return TRACE_TYPE_HANDLED;
-
- partial:
-        return TRACE_TYPE_PARTIAL_LINE;
-}
-
 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags)
 {
         struct ftrace_entry *field;
@@ -573,7 +548,6 @@ static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags)
 static struct trace_event trace_fn_event = {
         .type           = TRACE_FN,
         .trace          = trace_fn_trace,
-        .latency_trace  = trace_fn_latency,
         .raw            = trace_fn_raw,
         .hex            = trace_fn_hex,
         .binary         = trace_fn_bin,
@@ -705,7 +679,6 @@ static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
 static struct trace_event trace_ctx_event = {
         .type           = TRACE_CTX,
         .trace          = trace_ctx_print,
-        .latency_trace  = trace_ctx_print,
         .raw            = trace_ctx_raw,
         .hex            = trace_ctx_hex,
         .binary         = trace_ctxwake_bin,
@@ -714,7 +687,6 @@ static struct trace_event trace_ctx_event = {
 static struct trace_event trace_wake_event = {
         .type           = TRACE_WAKE,
         .trace          = trace_wake_print,
-        .latency_trace  = trace_wake_print,
         .raw            = trace_wake_raw,
         .hex            = trace_wake_hex,
         .binary         = trace_ctxwake_bin,
@@ -770,7 +742,6 @@ static enum print_line_t trace_special_bin(struct trace_iterator *iter,
 static struct trace_event trace_special_event = {
         .type           = TRACE_SPECIAL,
         .trace          = trace_special_print,
-        .latency_trace  = trace_special_print,
         .raw            = trace_special_print,
         .hex            = trace_special_hex,
         .binary         = trace_special_bin,
@@ -808,7 +779,6 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
 static struct trace_event trace_stack_event = {
         .type           = TRACE_STACK,
         .trace          = trace_stack_print,
-        .latency_trace  = trace_stack_print,
         .raw            = trace_special_print,
         .hex            = trace_special_hex,
         .binary         = trace_special_bin,
@@ -838,7 +808,6 @@ static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
 static struct trace_event trace_user_stack_event = {
         .type           = TRACE_USER_STACK,
         .trace          = trace_user_stack_print,
-        .latency_trace  = trace_user_stack_print,
         .raw            = trace_special_print,
         .hex            = trace_special_hex,
         .binary         = trace_special_bin,
@@ -883,7 +852,6 @@ static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags)
 static struct trace_event trace_print_event = {
         .type           = TRACE_PRINT,
         .trace          = trace_print_print,
-        .latency_trace  = trace_print_print,
         .raw            = trace_print_raw,
 };
 
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index 551a25a72217..8a34d688ed63 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -10,7 +10,6 @@ struct trace_event {
         struct hlist_node       node;
         int                     type;
         trace_print_func        trace;
-        trace_print_func        latency_trace;
         trace_print_func        raw;
         trace_print_func        hex;
         trace_print_func        binary;
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index db55f7aaa640..3c5ad6b2ec84 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -32,6 +32,8 @@ static raw_spinlock_t wakeup_lock =
 
 static void __wakeup_reset(struct trace_array *tr);
 
+static int save_lat_flag;
+
 #ifdef CONFIG_FUNCTION_TRACER
 /*
  * irqsoff uses its own tracer function to keep the overhead down:
@@ -324,6 +326,9 @@ static void stop_wakeup_tracer(struct trace_array *tr)
 
 static int __wakeup_tracer_init(struct trace_array *tr)
 {
+        save_lat_flag = trace_flags & TRACE_ITER_LATENCY_FMT;
+        trace_flags |= TRACE_ITER_LATENCY_FMT;
+
         tracing_max_latency = 0;
         wakeup_trace = tr;
         start_wakeup_tracer(tr);
@@ -347,6 +352,9 @@ static void wakeup_tracer_reset(struct trace_array *tr)
         stop_wakeup_tracer(tr);
         /* make sure we put back any tasks we are tracing */
         wakeup_reset(tr);
+
+        if (!save_lat_flag)
+                trace_flags &= ~TRACE_ITER_LATENCY_FMT;
 }
 
 static void wakeup_tracer_start(struct trace_array *tr)