Merge branch 'tip/perf/core-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull minor tracing updates and fixes from Steven Rostedt:
 "It seems that one of my old pull requests have slipped through.

  The changes are contained to just the files that I maintain, and are
  changes from others that I told I would get into this merge window.

  They have already been in linux-next for several weeks, and should be
  well tested."

* 'tip/perf/core-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Remove unnecessary WARN_ONCE's from tracing_buffers_splice_read
  tracing: Remove unneeded checks from the stack tracer
  tracing: Add a resize function to make one buffer equivalent to another buffer

2 files changed, 31 insertions, 33 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 61e081b4ba11..e5125677efa0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3034,6 +3034,31 @@ static void set_buffer_entries(struct trace_array *tr, unsigned long val)
                 tr->data[cpu]->entries = val;
 }
 
+/* resize @tr's buffer to the size of @size_tr's entries */
+static int resize_buffer_duplicate_size(struct trace_array *tr,
+                                        struct trace_array *size_tr, int cpu_id)
+{
+        int cpu, ret = 0;
+
+        if (cpu_id == RING_BUFFER_ALL_CPUS) {
+                for_each_tracing_cpu(cpu) {
+                        ret = ring_buffer_resize(tr->buffer,
+                                        size_tr->data[cpu]->entries, cpu);
+                        if (ret < 0)
+                                break;
+                        tr->data[cpu]->entries = size_tr->data[cpu]->entries;
+                }
+        } else {
+                ret = ring_buffer_resize(tr->buffer,
+                                        size_tr->data[cpu_id]->entries, cpu_id);
+                if (ret == 0)
+                        tr->data[cpu_id]->entries =
+                                size_tr->data[cpu_id]->entries;
+        }
+
+        return ret;
+}
+
 static int __tracing_resize_ring_buffer(unsigned long size, int cpu)
 {
         int ret;
@@ -3058,23 +3083,8 @@ static int __tracing_resize_ring_buffer(unsigned long size, int cpu)
 
         ret = ring_buffer_resize(max_tr.buffer, size, cpu);
         if (ret < 0) {
-                int r = 0;
-
-                if (cpu == RING_BUFFER_ALL_CPUS) {
-                        int i;
-                        for_each_tracing_cpu(i) {
-                                r = ring_buffer_resize(global_trace.buffer,
-                                                global_trace.data[i]->entries,
-                                                i);
-                                if (r < 0)
-                                        break;
-                        }
-                } else {
-                        r = ring_buffer_resize(global_trace.buffer,
-                                                global_trace.data[cpu]->entries,
-                                                cpu);
-                }
-
+                int r = resize_buffer_duplicate_size(&global_trace,
+                                                     &global_trace, cpu);
                 if (r < 0) {
                         /*
                          * AARGH! We are left with different
@@ -3212,17 +3222,11 @@ static int tracing_set_tracer(const char *buf)
 
         topts = create_trace_option_files(t);
         if (t->use_max_tr) {
-                int cpu;
                 /* we need to make per cpu buffer sizes equivalent */
-                for_each_tracing_cpu(cpu) {
-                        ret = ring_buffer_resize(max_tr.buffer,
-                                                global_trace.data[cpu]->entries,
-                                                cpu);
-                        if (ret < 0)
-                                goto out;
-                        max_tr.data[cpu]->entries =
-                                        global_trace.data[cpu]->entries;
-                }
+                ret = resize_buffer_duplicate_size(&max_tr, &global_trace,
+                                                   RING_BUFFER_ALL_CPUS);
+                if (ret < 0)
+                        goto out;
         }
 
         if (t->init) {
@@ -4271,13 +4275,11 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
                 return -ENOMEM;
 
         if (*ppos & (PAGE_SIZE - 1)) {
-                WARN_ONCE(1, "Ftrace: previous read must page-align\n");
                 ret = -EINVAL;
                 goto out;
         }
 
         if (len & (PAGE_SIZE - 1)) {
-                WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
                 if (len < PAGE_SIZE) {
                         ret = -EINVAL;
                         goto out;
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 0c1b165778e5..42ca822fc701 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -33,7 +33,6 @@ static unsigned long max_stack_size;
 static arch_spinlock_t max_stack_lock =
         (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 
-static int stack_trace_disabled __read_mostly;
 static DEFINE_PER_CPU(int, trace_active);
 static DEFINE_MUTEX(stack_sysctl_mutex);
 
@@ -116,9 +115,6 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip,
 {
         int cpu;
 
-        if (unlikely(!ftrace_enabled || stack_trace_disabled))
-                return;
-
         preempt_disable_notrace();
 
         cpu = raw_smp_processor_id();