#include "trace.h"
   
++ /* Global flag to disable all recording to ring buffers */
++ static int ring_buffers_off __read_mostly;
++ 
++ /**
++  * tracing_on - enable all tracing buffers
++  *
++  * This function enables all tracing buffers that may have been
++  * disabled with tracing_off.
++  */
++ void tracing_on(void)
++ {
++      ring_buffers_off = 0;
++ }
++ 
++ /**
++  * tracing_off - turn off all tracing buffers
++  *
++  * This function stops all tracing buffers from recording data.
++  * It does not disable any overhead the tracers themselves may
++  * be causing. This function simply causes all recording to
++  * the ring buffers to fail.
++  */
++ void tracing_off(void)
++ {
++      ring_buffers_off = 1;
++ }
++ 
+++#include "trace.h"
+++
   /* Up this if you want to test the TIME_EXTENTS and normalization */
   #define DEBUG_SHIFT 0
   
   struct ring_buffer_per_cpu {
        int                             cpu;
        struct ring_buffer              *buffer;
  -     spinlock_t                      lock;
+ +     spinlock_t                      reader_lock; /* serialize readers */
  +     raw_spinlock_t                  lock;
        struct lock_class_key           lock_key;
        struct list_head                pages;
        struct buffer_page              *head_page;     /* read from head */
        u64                             read_stamp;
   };
   
  +/* buffer may be either ring_buffer or ring_buffer_per_cpu */
   #define RB_WARN_ON(buffer, cond)                             \
  -     do {                                                    \
  -             if (unlikely(cond)) {                           \
  -                     atomic_inc(&buffer->record_disabled);   \
  -                     WARN_ON(1);                             \
  -             }                                               \
  -     } while (0)
  -
  -#define RB_WARN_ON_RET(buffer, cond)                         \
- -     do {                                                    \
- -             if (unlikely(cond)) {                           \
+ +     ({                                                      \
+ +             int _____ret = unlikely(cond);                  \
+ +             if (_____ret) {                                 \
                        atomic_inc(&buffer->record_disabled);   \
                        WARN_ON(1);                             \
  -                     return -1;                              \
                }                                               \
-       } while (0)
-  
-  #define RB_WARN_ON_RET(buffer, cond)                         \
-       do {                                                    \
-               if (unlikely(cond)) {                           \
-                       atomic_inc(&buffer->record_disabled);   \
-                       WARN_ON(1);                             \
-                       return;                                 \
-               }                                               \
-       } while (0)
-  
-  #define RB_WARN_ON_RET_INT(buffer, cond)                     \
-       do {                                                    \
-               if (unlikely(cond)) {                           \
-                       atomic_inc(&buffer->record_disabled);   \
-                       WARN_ON(1);                             \
-                       return -1;                              \
-               }                                               \
-       } while (0)
-  
-  #define RB_WARN_ON_RET_NULL(buffer, cond)                    \
-       do {                                                    \
-               if (unlikely(cond)) {                           \
-                       atomic_inc(&buffer->record_disabled);   \
-                       WARN_ON(1);                             \
-                       return NULL;                            \
-               }                                               \
- -     } while (0)
- -
- -#define RB_WARN_ON_ONCE(buffer, cond)                                \
- -     do {                                                    \
- -             static int once;                                \
- -             if (unlikely(cond) && !once) {                  \
- -                     once++;                                 \
-                       atomic_inc(&buffer->record_disabled);   \
-                       WARN_ON(1);                             \
-               }                                               \
-       } while (0)
-  
-  /* buffer must be ring_buffer not per_cpu */
-  #define RB_WARN_ON_UNLOCK(buffer, cond)                              \
-       do {                                                    \
-               if (unlikely(cond)) {                           \
-                       mutex_unlock(&buffer->mutex);           \
- -                     atomic_inc(&buffer->record_disabled);   \
- -                     WARN_ON(1);                             \
-                       return -1;                              \
- -             }                                               \
- -     } while (0)
+ +             _____ret;                                       \
+ +     })
   
   /**
    * check_pages - integrity check of buffer pages
        struct list_head *head = &cpu_buffer->pages;
        struct buffer_page *page, *tmp;
   
-       RB_WARN_ON_RET_INT(cpu_buffer, head->next->prev != head);
-       RB_WARN_ON_RET_INT(cpu_buffer, head->prev->next != head);
  -     RB_WARN_ON_RET(cpu_buffer, head->next->prev != head);
  -     RB_WARN_ON_RET(cpu_buffer, head->prev->next != head);
+ +     if (RB_WARN_ON(cpu_buffer, head->next->prev != head))
+ +             return -1;
+ +     if (RB_WARN_ON(cpu_buffer, head->prev->next != head))
+ +             return -1;
   
        list_for_each_entry_safe(page, tmp, head, list) {
-               RB_WARN_ON_RET_INT(cpu_buffer,
  -             RB_WARN_ON_RET(cpu_buffer,
- -                            page->list.next->prev != &page->list);
-               RB_WARN_ON_RET_INT(cpu_buffer,
  -             RB_WARN_ON_RET(cpu_buffer,
- -                            page->list.prev->next != &page->list);
+ +             if (RB_WARN_ON(cpu_buffer,
+ +                            page->list.next->prev != &page->list))
+ +                     return -1;
+ +             if (RB_WARN_ON(cpu_buffer,
+ +                            page->list.prev->next != &page->list))
+ +                     return -1;
        }
   
        return 0;
   
        cpu_buffer->cpu = cpu;
        cpu_buffer->buffer = buffer;
  -     spin_lock_init(&cpu_buffer->lock);
+ +     spin_lock_init(&cpu_buffer->reader_lock);
  +     cpu_buffer->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
        INIT_LIST_HEAD(&cpu_buffer->pages);
   
        page = kzalloc_node(ALIGN(sizeof(*page), cache_line_size()),
        synchronize_sched();
   
        for (i = 0; i < nr_pages; i++) {
-               RB_WARN_ON_RET(cpu_buffer, list_empty(&cpu_buffer->pages));
  -             BUG_ON(list_empty(&cpu_buffer->pages));
+ +             if (RB_WARN_ON(cpu_buffer, list_empty(&cpu_buffer->pages)))
+ +                     return;
                p = cpu_buffer->pages.next;
                page = list_entry(p, struct buffer_page, list);
                list_del_init(&page->list);
                free_buffer_page(page);
        }
-       RB_WARN_ON_RET(cpu_buffer, list_empty(&cpu_buffer->pages));
  -     BUG_ON(list_empty(&cpu_buffer->pages));
+ +     if (RB_WARN_ON(cpu_buffer, list_empty(&cpu_buffer->pages)))
+ +             return;
   
        rb_reset_cpu(cpu_buffer);
   
        synchronize_sched();
   
        for (i = 0; i < nr_pages; i++) {
-               RB_WARN_ON_RET(cpu_buffer, list_empty(pages));
  -             BUG_ON(list_empty(pages));
+ +             if (RB_WARN_ON(cpu_buffer, list_empty(pages)))
+ +                     return;
                p = pages->next;
                page = list_entry(p, struct buffer_page, list);
                list_del_init(&page->list);
        if (size < buffer_size) {
   
                /* easy case, just free pages */
-               RB_WARN_ON_UNLOCK(buffer, nr_pages >= buffer->pages);
  -             BUG_ON(nr_pages >= buffer->pages);
+ +             if (RB_WARN_ON(buffer, nr_pages >= buffer->pages)) {
+ +                     mutex_unlock(&buffer->mutex);
+ +                     return -1;
+ +             }
   
                rm_pages = buffer->pages - nr_pages;
   
         * add these pages to the cpu_buffers. Otherwise we just free
         * them all and return -ENOMEM;
         */
-       RB_WARN_ON_UNLOCK(buffer, nr_pages <= buffer->pages);
  -     BUG_ON(nr_pages <= buffer->pages);
+ +     if (RB_WARN_ON(buffer, nr_pages <= buffer->pages)) {
+ +             mutex_unlock(&buffer->mutex);
+ +             return -1;
+ +     }
  +
        new_pages = nr_pages - buffer->pages;
   
        for_each_buffer_cpu(buffer, cpu) {
                rb_insert_pages(cpu_buffer, &pages, new_pages);
        }
   
-       RB_WARN_ON_UNLOCK(buffer, !list_empty(&pages));
  -     BUG_ON(!list_empty(&pages));
+ +     if (RB_WARN_ON(buffer, !list_empty(&pages))) {
+ +             mutex_unlock(&buffer->mutex);
+ +             return -1;
+ +     }
   
    out:
        buffer->pages = nr_pages;
             head += rb_event_length(event)) {
   
                event = __rb_page_index(cpu_buffer->head_page, head);
-               RB_WARN_ON_RET(cpu_buffer, rb_null_event(event));
  -             BUG_ON(rb_null_event(event));
+ +             if (RB_WARN_ON(cpu_buffer, rb_null_event(event)))
+ +                     return;
                /* Only count data entries */
                if (event->type != RINGBUF_TYPE_DATA)
                        continue;
   
        /* We reserved something on the buffer */
   
-       RB_WARN_ON_RET_NULL(cpu_buffer, write > BUF_PAGE_SIZE);
  -     BUG_ON(write > BUF_PAGE_SIZE);
+ +     if (RB_WARN_ON(cpu_buffer, write > BUF_PAGE_SIZE))
+ +             return NULL;
   
        event = __rb_page_index(tail_page, tail);
        rb_update_event(event, type, length);
        reader = rb_get_reader_page(cpu_buffer);
   
        /* This function should not be called when buffer is empty */
-       RB_WARN_ON_RET(cpu_buffer, !reader);
  -     BUG_ON(!reader);
+ +     if (RB_WARN_ON(cpu_buffer, !reader))
+ +             return;
   
        event = rb_reader_event(cpu_buffer);
   
         * Check if we are at the end of the buffer.
         */
        if (iter->head >= rb_page_size(iter->head_page)) {
-               RB_WARN_ON_RET(buffer,
-                              iter->head_page == cpu_buffer->commit_page);
  -             BUG_ON(iter->head_page == cpu_buffer->commit_page);
+ +             if (RB_WARN_ON(buffer,
+ +                            iter->head_page == cpu_buffer->commit_page))
+ +                     return;
                rb_inc_iter(iter);
                return;
        }
         * This should not be called to advance the header if we are
         * at the tail of the buffer.
         */
-       RB_WARN_ON_RET(cpu_buffer,
  -     BUG_ON((iter->head_page == cpu_buffer->commit_page) &&
  -            (iter->head + length > rb_commit_index(cpu_buffer)));
+ +     if (RB_WARN_ON(cpu_buffer,
  +                    (iter->head_page == cpu_buffer->commit_page) &&
-                      (iter->head + length > rb_commit_index(cpu_buffer)));
+ +                    (iter->head + length > rb_commit_index(cpu_buffer))))
+ +             return;
   
        rb_update_iter_read_stamp(iter, event);
   
        atomic_inc(&cpu_buffer->record_disabled);
        synchronize_sched();
   
-       local_irq_save(flags);
  -     spin_lock_irqsave(&cpu_buffer->lock, flags);
+ +     spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
  +     __raw_spin_lock(&cpu_buffer->lock);
        ring_buffer_iter_reset(iter);
  -     spin_unlock_irqrestore(&cpu_buffer->lock, flags);
  +     __raw_spin_unlock(&cpu_buffer->lock);
-       local_irq_restore(flags);
+ +     spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
   
        return iter;
   }
        if (!cpu_isset(cpu, buffer->cpumask))
                return;
   
-       local_irq_save(flags);
  -     spin_lock_irqsave(&cpu_buffer->lock, flags);
+ +     spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ +
  +     __raw_spin_lock(&cpu_buffer->lock);
   
        rb_reset_cpu(cpu_buffer);
   
  -     spin_unlock_irqrestore(&cpu_buffer->lock, flags);
  +     __raw_spin_unlock(&cpu_buffer->lock);
-       local_irq_restore(flags);
+ +
+ +     spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
   }
   
   /**