Merge branch 'v3.10/topic/configs' of git://git.linaro.org/kernel/linux-linaro-stable...
[firefly-linux-kernel-4.4.55.git] / kernel / trace / trace.c
index 1226a98c9bef390166b59670d65b3d535a76611f..6dbdf277c8fedf308030cafc9e2ec66e14a31d0e 100644 (file)
@@ -232,23 +232,43 @@ int filter_current_check_discard(struct ring_buffer *buffer,
 }
 EXPORT_SYMBOL_GPL(filter_current_check_discard);
 
-cycle_t ftrace_now(int cpu)
+cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu)
 {
        u64 ts;
 
        /* Early boot up does not have a buffer yet */
-       if (!global_trace.trace_buffer.buffer)
+       if (!buf->buffer)
                return trace_clock_local();
 
-       ts = ring_buffer_time_stamp(global_trace.trace_buffer.buffer, cpu);
-       ring_buffer_normalize_time_stamp(global_trace.trace_buffer.buffer, cpu, &ts);
+       ts = ring_buffer_time_stamp(buf->buffer, cpu);
+       ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
 
        return ts;
 }
 
+cycle_t ftrace_now(int cpu)
+{
+       return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
+}
+
+/**
+ * tracing_is_enabled - Show if global_trace has been disabled
+ *
+ * Shows if the global trace has been enabled or not. It uses the
+ * mirror flag "buffer_disabled" to be used in fast paths such as for
+ * the irqsoff tracer. But it may be inaccurate due to races. If you
+ * need to know the accurate state, use tracing_is_on() which is a little
+ * slower, but accurate.
+ */
 int tracing_is_enabled(void)
 {
-       return tracing_is_on();
+       /*
+        * For quick access (irqsoff uses this in fast path), just
+        * return the mirror variable of the state of the ring buffer.
+        * It's a little racy, but we don't really care.
+        */
+       smp_rmb();
+       return !global_trace.buffer_disabled;
 }
 
 /*
@@ -361,6 +381,23 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
        TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |
        TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | TRACE_ITER_FUNCTION;
 
+void tracer_tracing_on(struct trace_array *tr)
+{
+       if (tr->trace_buffer.buffer)
+               ring_buffer_record_on(tr->trace_buffer.buffer);
+       /*
+        * This flag is looked at when buffers haven't been allocated
+        * yet, or by some tracers (like irqsoff), that just want to
+        * know if the ring buffer has been disabled, but it can handle
+        * races of where it gets disabled but we still do a record.
+        * As the check is in the fast path of the tracers, it is more
+        * important to be fast than accurate.
+        */
+       tr->buffer_disabled = 0;
+       /* Make the flag seen by readers */
+       smp_wmb();
+}
+
 /**
  * tracing_on - enable tracing buffers
  *
@@ -369,15 +406,7 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
  */
 void tracing_on(void)
 {
-       if (global_trace.trace_buffer.buffer)
-               ring_buffer_record_on(global_trace.trace_buffer.buffer);
-       /*
-        * This flag is only looked at when buffers haven't been
-        * allocated yet. We don't really care about the race
-        * between setting this flag and actually turning
-        * on the buffer.
-        */
-       global_trace.buffer_disabled = 0;
+       tracer_tracing_on(&global_trace);
 }
 EXPORT_SYMBOL_GPL(tracing_on);
 
@@ -395,6 +424,9 @@ int __trace_puts(unsigned long ip, const char *str, int size)
        unsigned long irq_flags;
        int alloc;
 
+       if (unlikely(tracing_selftest_running || tracing_disabled))
+               return 0;
+
        alloc = sizeof(*entry) + size + 2; /* possible \n added */
 
        local_save_flags(irq_flags);
@@ -435,6 +467,9 @@ int __trace_bputs(unsigned long ip, const char *str)
        unsigned long irq_flags;
        int size = sizeof(struct bputs_entry);
 
+       if (unlikely(tracing_selftest_running || tracing_disabled))
+               return 0;
+
        local_save_flags(irq_flags);
        buffer = global_trace.trace_buffer.buffer;
        event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
@@ -571,6 +606,23 @@ void tracing_snapshot_alloc(void)
 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
 #endif /* CONFIG_TRACER_SNAPSHOT */
 
+void tracer_tracing_off(struct trace_array *tr)
+{
+       if (tr->trace_buffer.buffer)
+               ring_buffer_record_off(tr->trace_buffer.buffer);
+       /*
+        * This flag is looked at when buffers haven't been allocated
+        * yet, or by some tracers (like irqsoff), that just want to
+        * know if the ring buffer has been disabled, but it can handle
+        * races of where it gets disabled but we still do a record.
+        * As the check is in the fast path of the tracers, it is more
+        * important to be fast than accurate.
+        */
+       tr->buffer_disabled = 1;
+       /* Make the flag seen by readers */
+       smp_wmb();
+}
+
 /**
  * tracing_off - turn off tracing buffers
  *
@@ -581,26 +633,29 @@ EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
  */
 void tracing_off(void)
 {
-       if (global_trace.trace_buffer.buffer)
-               ring_buffer_record_off(global_trace.trace_buffer.buffer);
-       /*
-        * This flag is only looked at when buffers haven't been
-        * allocated yet. We don't really care about the race
-        * between setting this flag and actually turning
-        * on the buffer.
-        */
-       global_trace.buffer_disabled = 1;
+       tracer_tracing_off(&global_trace);
 }
 EXPORT_SYMBOL_GPL(tracing_off);
 
+/**
+ * tracer_tracing_is_on - show real state of ring buffer enabled
+ * @tr : the trace array to know if ring buffer is enabled
+ *
+ * Shows real state of the ring buffer if it is enabled or not.
+ */
+int tracer_tracing_is_on(struct trace_array *tr)
+{
+       if (tr->trace_buffer.buffer)
+               return ring_buffer_record_is_on(tr->trace_buffer.buffer);
+       return !tr->buffer_disabled;
+}
+
 /**
  * tracing_is_on - show state of ring buffers enabled
  */
 int tracing_is_on(void)
 {
-       if (global_trace.trace_buffer.buffer)
-               return ring_buffer_record_is_on(global_trace.trace_buffer.buffer);
-       return !global_trace.buffer_disabled;
+       return tracer_tracing_is_on(&global_trace);
 }
 EXPORT_SYMBOL_GPL(tracing_is_on);
 
@@ -777,9 +832,12 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
        if (isspace(ch)) {
                parser->buffer[parser->idx] = 0;
                parser->cont = false;
-       } else {
+       } else if (parser->idx < parser->size - 1) {
                parser->cont = true;
                parser->buffer[parser->idx++] = ch;
+       } else {
+               ret = -EINVAL;
+               goto out;
        }
 
        *ppos += read;
@@ -1150,7 +1208,7 @@ void tracing_reset_online_cpus(struct trace_buffer *buf)
        /* Make sure all commits have finished */
        synchronize_sched();
 
-       buf->time_start = ftrace_now(buf->cpu);
+       buf->time_start = buffer_ftrace_now(buf, buf->cpu);
 
        for_each_online_cpu(cpu)
                ring_buffer_reset_cpu(buffer, cpu);
@@ -1158,11 +1216,6 @@ void tracing_reset_online_cpus(struct trace_buffer *buf)
        ring_buffer_record_enable(buffer);
 }
 
-void tracing_reset_current(int cpu)
-{
-       tracing_reset(&global_trace.trace_buffer, cpu);
-}
-
 /* Must have trace_types_lock held */
 void tracing_reset_all_online_cpus(void)
 {
@@ -2790,6 +2843,17 @@ static int s_show(struct seq_file *m, void *v)
        return 0;
 }
 
+/*
+ * Should be used after trace_array_get(), trace_types_lock
+ * ensures that i_cdev was already initialized.
+ */
+static inline int tracing_get_cpu(struct inode *inode)
+{
+       if (inode->i_cdev) /* See trace_create_cpu_file() */
+               return (long)inode->i_cdev - 1;
+       return RING_BUFFER_ALL_CPUS;
+}
+
 static const struct seq_operations tracer_seq_ops = {
        .start          = s_start,
        .next           = s_next,
@@ -2798,9 +2862,9 @@ static const struct seq_operations tracer_seq_ops = {
 };
 
 static struct trace_iterator *
-__tracing_open(struct trace_array *tr, struct trace_cpu *tc,
-              struct inode *inode, struct file *file, bool snapshot)
+__tracing_open(struct inode *inode, struct file *file, bool snapshot)
 {
+       struct trace_array *tr = inode->i_private;
        struct trace_iterator *iter;
        int cpu;
 
@@ -2841,8 +2905,8 @@ __tracing_open(struct trace_array *tr, struct trace_cpu *tc,
                iter->trace_buffer = &tr->trace_buffer;
        iter->snapshot = snapshot;
        iter->pos = -1;
+       iter->cpu_file = tracing_get_cpu(inode);
        mutex_init(&iter->mutex);
-       iter->cpu_file = tc->cpu;
 
        /* Notify the tracer early; before we stop tracing. */
        if (iter->trace && iter->trace->open)
@@ -2918,44 +2982,22 @@ int tracing_open_generic_tr(struct inode *inode, struct file *filp)
        filp->private_data = inode->i_private;
 
        return 0;
-
-}
-
-int tracing_open_generic_tc(struct inode *inode, struct file *filp)
-{
-       struct trace_cpu *tc = inode->i_private;
-       struct trace_array *tr = tc->tr;
-
-       if (tracing_disabled)
-               return -ENODEV;
-
-       if (trace_array_get(tr) < 0)
-               return -ENODEV;
-
-       filp->private_data = inode->i_private;
-
-       return 0;
-
 }
 
 static int tracing_release(struct inode *inode, struct file *file)
 {
+       struct trace_array *tr = inode->i_private;
        struct seq_file *m = file->private_data;
        struct trace_iterator *iter;
-       struct trace_array *tr;
        int cpu;
 
-       /* Writes do not use seq_file, need to grab tr from inode */
        if (!(file->f_mode & FMODE_READ)) {
-               struct trace_cpu *tc = inode->i_private;
-
-               trace_array_put(tc->tr);
+               trace_array_put(tr);
                return 0;
        }
 
+       /* Writes do not use seq_file */
        iter = m->private;
-       tr = iter->tr;
-
        mutex_lock(&trace_types_lock);
 
        for_each_tracing_cpu(cpu) {
@@ -2991,15 +3033,6 @@ static int tracing_release_generic_tr(struct inode *inode, struct file *file)
        return 0;
 }
 
-static int tracing_release_generic_tc(struct inode *inode, struct file *file)
-{
-       struct trace_cpu *tc = inode->i_private;
-       struct trace_array *tr = tc->tr;
-
-       trace_array_put(tr);
-       return 0;
-}
-
 static int tracing_single_release_tr(struct inode *inode, struct file *file)
 {
        struct trace_array *tr = inode->i_private;
@@ -3011,8 +3044,7 @@ static int tracing_single_release_tr(struct inode *inode, struct file *file)
 
 static int tracing_open(struct inode *inode, struct file *file)
 {
-       struct trace_cpu *tc = inode->i_private;
-       struct trace_array *tr = tc->tr;
+       struct trace_array *tr = inode->i_private;
        struct trace_iterator *iter;
        int ret = 0;
 
@@ -3020,16 +3052,17 @@ static int tracing_open(struct inode *inode, struct file *file)
                return -ENODEV;
 
        /* If this file was open for write, then erase contents */
-       if ((file->f_mode & FMODE_WRITE) &&
-           (file->f_flags & O_TRUNC)) {
-               if (tc->cpu == RING_BUFFER_ALL_CPUS)
+       if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+               int cpu = tracing_get_cpu(inode);
+
+               if (cpu == RING_BUFFER_ALL_CPUS)
                        tracing_reset_online_cpus(&tr->trace_buffer);
                else
-                       tracing_reset(&tr->trace_buffer, tc->cpu);
+                       tracing_reset(&tr->trace_buffer, cpu);
        }
 
        if (file->f_mode & FMODE_READ) {
-               iter = __tracing_open(tr, tc, inode, file, false);
+               iter = __tracing_open(inode, file, false);
                if (IS_ERR(iter))
                        ret = PTR_ERR(iter);
                else if (trace_flags & TRACE_ITER_LATENCY_FMT)
@@ -3895,8 +3928,7 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf,
 
 static int tracing_open_pipe(struct inode *inode, struct file *filp)
 {
-       struct trace_cpu *tc = inode->i_private;
-       struct trace_array *tr = tc->tr;
+       struct trace_array *tr = inode->i_private;
        struct trace_iterator *iter;
        int ret = 0;
 
@@ -3942,9 +3974,9 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
        if (trace_clocks[tr->clock_id].in_ns)
                iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
 
-       iter->cpu_file = tc->cpu;
-       iter->tr = tc->tr;
-       iter->trace_buffer = &tc->tr->trace_buffer;
+       iter->tr = tr;
+       iter->trace_buffer = &tr->trace_buffer;
+       iter->cpu_file = tracing_get_cpu(inode);
        mutex_init(&iter->mutex);
        filp->private_data = iter;
 
@@ -3967,8 +3999,7 @@ fail:
 static int tracing_release_pipe(struct inode *inode, struct file *file)
 {
        struct trace_iterator *iter = file->private_data;
-       struct trace_cpu *tc = inode->i_private;
-       struct trace_array *tr = tc->tr;
+       struct trace_array *tr = inode->i_private;
 
        mutex_lock(&trace_types_lock);
 
@@ -4060,7 +4091,7 @@ static int tracing_wait_pipe(struct file *filp)
                 *
                 * iter->pos will be 0 if we haven't read anything.
                 */
-               if (!tracing_is_enabled() && iter->pos)
+               if (!tracing_is_on() && iter->pos)
                        break;
        }
 
@@ -4322,15 +4353,16 @@ static ssize_t
 tracing_entries_read(struct file *filp, char __user *ubuf,
                     size_t cnt, loff_t *ppos)
 {
-       struct trace_cpu *tc = filp->private_data;
-       struct trace_array *tr = tc->tr;
+       struct inode *inode = file_inode(filp);
+       struct trace_array *tr = inode->i_private;
+       int cpu = tracing_get_cpu(inode);
        char buf[64];
        int r = 0;
        ssize_t ret;
 
        mutex_lock(&trace_types_lock);
 
-       if (tc->cpu == RING_BUFFER_ALL_CPUS) {
+       if (cpu == RING_BUFFER_ALL_CPUS) {
                int cpu, buf_size_same;
                unsigned long size;
 
@@ -4357,7 +4389,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf,
                } else
                        r = sprintf(buf, "X\n");
        } else
-               r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10);
+               r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
 
        mutex_unlock(&trace_types_lock);
 
@@ -4369,7 +4401,8 @@ static ssize_t
 tracing_entries_write(struct file *filp, const char __user *ubuf,
                      size_t cnt, loff_t *ppos)
 {
-       struct trace_cpu *tc = filp->private_data;
+       struct inode *inode = file_inode(filp);
+       struct trace_array *tr = inode->i_private;
        unsigned long val;
        int ret;
 
@@ -4383,8 +4416,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
 
        /* value is in KB */
        val <<= 10;
-
-       ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu);
+       ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
        if (ret < 0)
                return ret;
 
@@ -4603,12 +4635,12 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
         * New clock may not be consistent with the previous clock.
         * Reset the buffer so that it doesn't have incomparable timestamps.
         */
-       tracing_reset_online_cpus(&global_trace.trace_buffer);
+       tracing_reset_online_cpus(&tr->trace_buffer);
 
 #ifdef CONFIG_TRACER_MAX_TRACE
        if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
                ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
-       tracing_reset_online_cpus(&global_trace.max_buffer);
+       tracing_reset_online_cpus(&tr->max_buffer);
 #endif
 
        mutex_unlock(&trace_types_lock);
@@ -4645,8 +4677,7 @@ struct ftrace_buffer_info {
 #ifdef CONFIG_TRACER_SNAPSHOT
 static int tracing_snapshot_open(struct inode *inode, struct file *file)
 {
-       struct trace_cpu *tc = inode->i_private;
-       struct trace_array *tr = tc->tr;
+       struct trace_array *tr = inode->i_private;
        struct trace_iterator *iter;
        struct seq_file *m;
        int ret = 0;
@@ -4655,7 +4686,7 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file)
                return -ENODEV;
 
        if (file->f_mode & FMODE_READ) {
-               iter = __tracing_open(tr, tc, inode, file, true);
+               iter = __tracing_open(inode, file, true);
                if (IS_ERR(iter))
                        ret = PTR_ERR(iter);
        } else {
@@ -4672,8 +4703,8 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file)
                ret = 0;
 
                iter->tr = tr;
-               iter->trace_buffer = &tc->tr->max_buffer;
-               iter->cpu_file = tc->cpu;
+               iter->trace_buffer = &tr->max_buffer;
+               iter->cpu_file = tracing_get_cpu(inode);
                m->private = iter;
                file->private_data = m;
        }
@@ -4832,11 +4863,11 @@ static const struct file_operations tracing_pipe_fops = {
 };
 
 static const struct file_operations tracing_entries_fops = {
-       .open           = tracing_open_generic_tc,
+       .open           = tracing_open_generic_tr,
        .read           = tracing_entries_read,
        .write          = tracing_entries_write,
        .llseek         = generic_file_llseek,
-       .release        = tracing_release_generic_tc,
+       .release        = tracing_release_generic_tr,
 };
 
 static const struct file_operations tracing_total_entries_fops = {
@@ -4888,8 +4919,7 @@ static const struct file_operations snapshot_raw_fops = {
 
 static int tracing_buffers_open(struct inode *inode, struct file *filp)
 {
-       struct trace_cpu *tc = inode->i_private;
-       struct trace_array *tr = tc->tr;
+       struct trace_array *tr = inode->i_private;
        struct ftrace_buffer_info *info;
        int ret;
 
@@ -4908,7 +4938,7 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
        mutex_lock(&trace_types_lock);
 
        info->iter.tr           = tr;
-       info->iter.cpu_file     = tc->cpu;
+       info->iter.cpu_file     = tracing_get_cpu(inode);
        info->iter.trace        = tr->current_trace;
        info->iter.trace_buffer = &tr->trace_buffer;
        info->spare             = NULL;
@@ -5225,14 +5255,14 @@ static ssize_t
 tracing_stats_read(struct file *filp, char __user *ubuf,
                   size_t count, loff_t *ppos)
 {
-       struct trace_cpu *tc = filp->private_data;
-       struct trace_array *tr = tc->tr;
+       struct inode *inode = file_inode(filp);
+       struct trace_array *tr = inode->i_private;
        struct trace_buffer *trace_buf = &tr->trace_buffer;
+       int cpu = tracing_get_cpu(inode);
        struct trace_seq *s;
        unsigned long cnt;
        unsigned long long t;
        unsigned long usec_rem;
-       int cpu = tc->cpu;
 
        s = kmalloc(sizeof(*s), GFP_KERNEL);
        if (!s)
@@ -5285,10 +5315,10 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
 }
 
 static const struct file_operations tracing_stats_fops = {
-       .open           = tracing_open_generic_tc,
+       .open           = tracing_open_generic_tr,
        .read           = tracing_stats_read,
        .llseek         = generic_file_llseek,
-       .release        = tracing_release_generic_tc,
+       .release        = tracing_release_generic_tr,
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -5477,10 +5507,20 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
        return tr->percpu_dir;
 }
 
+static struct dentry *
+trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
+                     void *data, long cpu, const struct file_operations *fops)
+{
+       struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
+
+       if (ret) /* See tracing_get_cpu() */
+               ret->d_inode->i_cdev = (void *)(cpu + 1);
+       return ret;
+}
+
 static void
 tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 {
-       struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
        struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
        struct dentry *d_cpu;
        char cpu_dir[30]; /* 30 characters should be more than enough */
@@ -5496,28 +5536,28 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
        }
 
        /* per cpu trace_pipe */
-       trace_create_file("trace_pipe", 0444, d_cpu,
-                       (void *)&data->trace_cpu, &tracing_pipe_fops);
+       trace_create_cpu_file("trace_pipe", 0444, d_cpu,
+                               tr, cpu, &tracing_pipe_fops);
 
        /* per cpu trace */
-       trace_create_file("trace", 0644, d_cpu,
-                       (void *)&data->trace_cpu, &tracing_fops);
+       trace_create_cpu_file("trace", 0644, d_cpu,
+                               tr, cpu, &tracing_fops);
 
-       trace_create_file("trace_pipe_raw", 0444, d_cpu,
-                       (void *)&data->trace_cpu, &tracing_buffers_fops);
+       trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
+                               tr, cpu, &tracing_buffers_fops);
 
-       trace_create_file("stats", 0444, d_cpu,
-                       (void *)&data->trace_cpu, &tracing_stats_fops);
+       trace_create_cpu_file("stats", 0444, d_cpu,
+                               tr, cpu, &tracing_stats_fops);
 
-       trace_create_file("buffer_size_kb", 0444, d_cpu,
-                       (void *)&data->trace_cpu, &tracing_entries_fops);
+       trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
+                               tr, cpu, &tracing_entries_fops);
 
 #ifdef CONFIG_TRACER_SNAPSHOT
-       trace_create_file("snapshot", 0644, d_cpu,
-                         (void *)&data->trace_cpu, &snapshot_fops);
+       trace_create_cpu_file("snapshot", 0644, d_cpu,
+                               tr, cpu, &snapshot_fops);
 
-       trace_create_file("snapshot_raw", 0444, d_cpu,
-                       (void *)&data->trace_cpu, &snapshot_raw_fops);
+       trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
+                               tr, cpu, &snapshot_raw_fops);
 #endif
 }
 
@@ -5772,15 +5812,10 @@ rb_simple_read(struct file *filp, char __user *ubuf,
               size_t cnt, loff_t *ppos)
 {
        struct trace_array *tr = filp->private_data;
-       struct ring_buffer *buffer = tr->trace_buffer.buffer;
        char buf[64];
        int r;
 
-       if (buffer)
-               r = ring_buffer_record_is_on(buffer);
-       else
-               r = 0;
-
+       r = tracer_tracing_is_on(tr);
        r = sprintf(buf, "%d\n", r);
 
        return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
@@ -5802,11 +5837,11 @@ rb_simple_write(struct file *filp, const char __user *ubuf,
        if (buffer) {
                mutex_lock(&trace_types_lock);
                if (val) {
-                       ring_buffer_record_on(buffer);
+                       tracer_tracing_on(tr);
                        if (tr->current_trace->start)
                                tr->current_trace->start(tr);
                } else {
-                       ring_buffer_record_off(buffer);
+                       tracer_tracing_off(tr);
                        if (tr->current_trace->stop)
                                tr->current_trace->stop(tr);
                }
@@ -5849,6 +5884,8 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size
 
        rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
 
+       buf->tr = tr;
+
        buf->buffer = ring_buffer_alloc(size, rb_flags);
        if (!buf->buffer)
                return -ENOMEM;
@@ -6085,13 +6122,13 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
                          tr, &tracing_iter_fops);
 
        trace_create_file("trace", 0644, d_tracer,
-                       (void *)&tr->trace_cpu, &tracing_fops);
+                         tr, &tracing_fops);
 
        trace_create_file("trace_pipe", 0444, d_tracer,
-                       (void *)&tr->trace_cpu, &tracing_pipe_fops);
+                         tr, &tracing_pipe_fops);
 
        trace_create_file("buffer_size_kb", 0644, d_tracer,
-                       (void *)&tr->trace_cpu, &tracing_entries_fops);
+                         tr, &tracing_entries_fops);
 
        trace_create_file("buffer_total_size_kb", 0444, d_tracer,
                          tr, &tracing_total_entries_fops);
@@ -6106,11 +6143,11 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
                          &trace_clock_fops);
 
        trace_create_file("tracing_on", 0644, d_tracer,
-                           tr, &rb_simple_fops);
+                         tr, &rb_simple_fops);
 
 #ifdef CONFIG_TRACER_SNAPSHOT
        trace_create_file("snapshot", 0644, d_tracer,
-                         (void *)&tr->trace_cpu, &snapshot_fops);
+                         tr, &snapshot_fops);
 #endif
 
        for_each_tracing_cpu(cpu)