ring-buffer: Merge separate resize loops

There are 2 separate loops to resize cpu buffers that are online and
offline. Merge them to make the code look better.

Also change the name from update_completion to update_done to allow
shorter lines.

Link: http://lkml.kernel.org/r/1337372991-14783-1-git-send-email-vnagarnaik@google.com

Cc: Laurent Chavey <chavey@google.com>
Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 15 insertions, 26 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 68388f876d4..6420cda6233 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -473,7 +473,7 @@ struct ring_buffer_per_cpu {
         int                             nr_pages_to_update;
         struct list_head                new_pages; /* new pages to add */
         struct work_struct              update_pages_work;
-        struct completion               update_completion;
+        struct completion               update_done;
 };
 
 struct ring_buffer {
@@ -1058,7 +1058,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int nr_pages, int cpu)
         lockdep_set_class(&cpu_buffer->reader_lock, buffer->reader_lock_key);
         cpu_buffer->lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
         INIT_WORK(&cpu_buffer->update_pages_work, update_pages_handler);
-        init_completion(&cpu_buffer->update_completion);
+        init_completion(&cpu_buffer->update_done);
 
         bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
                             GFP_KERNEL, cpu_to_node(cpu));
@@ -1461,7 +1461,7 @@ static void update_pages_handler(struct work_struct *work)
         struct ring_buffer_per_cpu *cpu_buffer = container_of(work,
                         struct ring_buffer_per_cpu, update_pages_work);
         rb_update_pages(cpu_buffer);
-        complete(&cpu_buffer->update_completion);
+        complete(&cpu_buffer->update_done);
 }
 
 /**
@@ -1534,39 +1534,29 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
                 get_online_cpus();
                 /*
                  * Fire off all the required work handlers
-                 * Look out for offline CPUs
-                 */
-                for_each_buffer_cpu(buffer, cpu) {
-                        cpu_buffer = buffer->buffers[cpu];
-                        if (!cpu_buffer->nr_pages_to_update ||
-                            !cpu_online(cpu))
-                                continue;
-
-                        schedule_work_on(cpu, &cpu_buffer->update_pages_work);
-                }
-                /*
-                 * This loop is for the CPUs that are not online.
-                 * We can't schedule anything on them, but it's not necessary
+                 * We can't schedule on offline CPUs, but it's not necessary
                  * since we can change their buffer sizes without any race.
                  */
                 for_each_buffer_cpu(buffer, cpu) {
                         cpu_buffer = buffer->buffers[cpu];
-                        if (!cpu_buffer->nr_pages_to_update ||
-                            cpu_online(cpu))
+                        if (!cpu_buffer->nr_pages_to_update)
                                 continue;
 
-                        rb_update_pages(cpu_buffer);
+                        if (cpu_online(cpu))
+                                schedule_work_on(cpu,
+                                                &cpu_buffer->update_pages_work);
+                        else
+                                rb_update_pages(cpu_buffer);
                 }
 
                 /* wait for all the updates to complete */
                 for_each_buffer_cpu(buffer, cpu) {
                         cpu_buffer = buffer->buffers[cpu];
-                        if (!cpu_buffer->nr_pages_to_update ||
-                            !cpu_online(cpu))
+                        if (!cpu_buffer->nr_pages_to_update)
                                 continue;
 
-                        wait_for_completion(&cpu_buffer->update_completion);
-                        /* reset this value */
+                        if (cpu_online(cpu))
+                                wait_for_completion(&cpu_buffer->update_done);
                         cpu_buffer->nr_pages_to_update = 0;
                 }
 
@@ -1593,13 +1583,12 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
                 if (cpu_online(cpu_id)) {
                         schedule_work_on(cpu_id,
                                          &cpu_buffer->update_pages_work);
-                        wait_for_completion(&cpu_buffer->update_completion);
+                        wait_for_completion(&cpu_buffer->update_done);
                 } else
                         rb_update_pages(cpu_buffer);
 
-                put_online_cpus();
-                /* reset this value */
                 cpu_buffer->nr_pages_to_update = 0;
+                put_online_cpus();
         }
 
  out: