Merge commit 'v2.6.37-rc2' into sched/core

Merge reason: Move to a .37-rc base.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

8 files changed, 190 insertions, 187 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 959f8d6c8cc..7b8ec028154 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -23,7 +23,6 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/debugfs.h>
-#include <linux/smp_lock.h>
 #include <linux/time.h>
 #include <linux/uaccess.h>
 
@@ -169,7 +168,6 @@ static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
                                  BLK_TC_ACT(BLK_TC_WRITE) };
 
-#define BLK_TC_HARDBARRIER      BLK_TC_BARRIER
 #define BLK_TC_RAHEAD           BLK_TC_AHEAD
 
 /* The ilog2() calls fall out because they're constant */
@@ -197,7 +195,6 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
                 return;
 
         what |= ddir_act[rw & WRITE];
-        what |= MASK_TC_BIT(rw, HARDBARRIER);
         what |= MASK_TC_BIT(rw, SYNC);
         what |= MASK_TC_BIT(rw, RAHEAD);
         what |= MASK_TC_BIT(rw, META);
@@ -326,6 +323,7 @@ static const struct file_operations blk_dropped_fops = {
         .owner =        THIS_MODULE,
         .open =         blk_dropped_open,
         .read =         blk_dropped_read,
+        .llseek =       default_llseek,
 };
 
 static int blk_msg_open(struct inode *inode, struct file *filp)
@@ -365,6 +363,7 @@ static const struct file_operations blk_msg_fops = {
         .owner =        THIS_MODULE,
         .open =         blk_msg_open,
         .write =        blk_msg_write,
+        .llseek =       noop_llseek,
 };
 
 /*
@@ -639,7 +638,6 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
         if (!q)
                 return -ENXIO;
 
-        lock_kernel();
         mutex_lock(&bdev->bd_mutex);
 
         switch (cmd) {
@@ -667,7 +665,6 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
         }
 
         mutex_unlock(&bdev->bd_mutex);
-        unlock_kernel();
         return ret;
 }
 
@@ -1652,10 +1649,9 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
         struct block_device *bdev;
         ssize_t ret = -ENXIO;
 
-        lock_kernel();
         bdev = bdget(part_devt(p));
         if (bdev == NULL)
-                goto out_unlock_kernel;
+                goto out;
 
         q = blk_trace_get_queue(bdev);
         if (q == NULL)
@@ -1683,8 +1679,7 @@ out_unlock_bdev:
         mutex_unlock(&bdev->bd_mutex);
 out_bdput:
         bdput(bdev);
-out_unlock_kernel:
-        unlock_kernel();
+out:
         return ret;
 }
 
@@ -1714,11 +1709,10 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
 
         ret = -ENXIO;
 
-        lock_kernel();
         p = dev_to_part(dev);
         bdev = bdget(part_devt(p));
         if (bdev == NULL)
-                goto out_unlock_kernel;
+                goto out;
 
         q = blk_trace_get_queue(bdev);
         if (q == NULL)
@@ -1753,8 +1747,6 @@ out_unlock_bdev:
         mutex_unlock(&bdev->bd_mutex);
 out_bdput:
         bdput(bdev);
-out_unlock_kernel:
-        unlock_kernel();
 out:
         return ret ? ret : count;
 }
@@ -1813,8 +1805,6 @@ void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
 
         if (rw & REQ_RAHEAD)
                 rwbs[i++] = 'A';
-        if (rw & REQ_HARDBARRIER)
-                rwbs[i++] = 'B';
         if (rw & REQ_SYNC)
                 rwbs[i++] = 'S';
         if (rw & REQ_META)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index ebd80d50c47..f3dadae8388 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -800,6 +800,7 @@ static const struct file_operations ftrace_profile_fops = {
         .open           = tracing_open_generic,
         .read           = ftrace_profile_read,
         .write          = ftrace_profile_write,
+        .llseek         = default_llseek,
 };
 
 /* used to initialize the real stat files */
@@ -2669,6 +2670,7 @@ static const struct file_operations ftrace_graph_fops = {
         .read           = seq_read,
         .write          = ftrace_graph_write,
         .release        = ftrace_graph_release,
+        .llseek         = seq_lseek,
 };
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index c5a632a669e..9ed509a015d 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -224,6 +224,9 @@ enum {
         RB_LEN_TIME_STAMP = 16,
 };
 
+#define skip_time_extend(event) \
+        ((struct ring_buffer_event *)((char *)event + RB_LEN_TIME_EXTEND))
+
 static inline int rb_null_event(struct ring_buffer_event *event)
 {
         return event->type_len == RINGBUF_TYPE_PADDING && !event->time_delta;
@@ -248,8 +251,12 @@ rb_event_data_length(struct ring_buffer_event *event)
         return length + RB_EVNT_HDR_SIZE;
 }
 
-/* inline for ring buffer fast paths */
-static unsigned
+/*
+ * Return the length of the given event. Will return
+ * the length of the time extend if the event is a
+ * time extend.
+ */
+static inline unsigned
 rb_event_length(struct ring_buffer_event *event)
 {
         switch (event->type_len) {
@@ -274,13 +281,41 @@ rb_event_length(struct ring_buffer_event *event)
         return 0;
 }
 
+/*
+ * Return total length of time extend and data,
+ *   or just the event length for all other events.
+ */
+static inline unsigned
+rb_event_ts_length(struct ring_buffer_event *event)
+{
+        unsigned len = 0;
+
+        if (event->type_len == RINGBUF_TYPE_TIME_EXTEND) {
+                /* time extends include the data event after it */
+                len = RB_LEN_TIME_EXTEND;
+                event = skip_time_extend(event);
+        }
+        return len + rb_event_length(event);
+}
+
 /**
  * ring_buffer_event_length - return the length of the event
  * @event: the event to get the length of
+ *
+ * Returns the size of the data load of a data event.
+ * If the event is something other than a data event, it
+ * returns the size of the event itself. With the exception
+ * of a TIME EXTEND, where it still returns the size of the
+ * data load of the data event after it.
  */
 unsigned ring_buffer_event_length(struct ring_buffer_event *event)
 {
-        unsigned length = rb_event_length(event);
+        unsigned length;
+
+        if (event->type_len == RINGBUF_TYPE_TIME_EXTEND)
+                event = skip_time_extend(event);
+
+        length = rb_event_length(event);
         if (event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
                 return length;
         length -= RB_EVNT_HDR_SIZE;
@@ -294,6 +329,8 @@ EXPORT_SYMBOL_GPL(ring_buffer_event_length);
 static void *
 rb_event_data(struct ring_buffer_event *event)
 {
+        if (event->type_len == RINGBUF_TYPE_TIME_EXTEND)
+                event = skip_time_extend(event);
         BUG_ON(event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
         /* If length is in len field, then array[0] has the data */
         if (event->type_len)
@@ -404,9 +441,6 @@ static inline int test_time_stamp(u64 delta)
 /* Max payload is BUF_PAGE_SIZE - header (8bytes) */
 #define BUF_MAX_DATA_SIZE (BUF_PAGE_SIZE - (sizeof(u32) * 2))
 
-/* Max number of timestamps that can fit on a page */
-#define RB_TIMESTAMPS_PER_PAGE  (BUF_PAGE_SIZE / RB_LEN_TIME_EXTEND)
-
 int ring_buffer_print_page_header(struct trace_seq *s)
 {
         struct buffer_data_page field;
@@ -1546,6 +1580,25 @@ static void rb_inc_iter(struct ring_buffer_iter *iter)
         iter->head = 0;
 }
 
+/* Slow path, do not inline */
+static noinline struct ring_buffer_event *
+rb_add_time_stamp(struct ring_buffer_event *event, u64 delta)
+{
+        event->type_len = RINGBUF_TYPE_TIME_EXTEND;
+
+        /* Not the first event on the page? */
+        if (rb_event_index(event)) {
+                event->time_delta = delta & TS_MASK;
+                event->array[0] = delta >> TS_SHIFT;
+        } else {
+                /* nope, just zero it */
+                event->time_delta = 0;
+                event->array[0] = 0;
+        }
+
+        return skip_time_extend(event);
+}
+
 /**
  * ring_buffer_update_event - update event type and data
  * @event: the even to update
@@ -1558,28 +1611,31 @@ static void rb_inc_iter(struct ring_buffer_iter *iter)
  * data field.
  */
 static void
-rb_update_event(struct ring_buffer_event *event,
-                         unsigned type, unsigned length)
+rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
+                struct ring_buffer_event *event, unsigned length,
+                int add_timestamp, u64 delta)
 {
-        event->type_len = type;
-
-        switch (type) {
-
-        case RINGBUF_TYPE_PADDING:
-        case RINGBUF_TYPE_TIME_EXTEND:
-        case RINGBUF_TYPE_TIME_STAMP:
-                break;
+        /* Only a commit updates the timestamp */
+        if (unlikely(!rb_event_is_commit(cpu_buffer, event)))
+                delta = 0;
 
-        case 0:
-                length -= RB_EVNT_HDR_SIZE;
-                if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT)
-                        event->array[0] = length;
-                else
-                        event->type_len = DIV_ROUND_UP(length, RB_ALIGNMENT);
-                break;
-        default:
-                BUG();
+        /*
+         * If we need to add a timestamp, then we
+         * add it to the start of the resevered space.
+         */
+        if (unlikely(add_timestamp)) {
+                event = rb_add_time_stamp(event, delta);
+                length -= RB_LEN_TIME_EXTEND;
+                delta = 0;
         }
+
+        event->time_delta = delta;
+        length -= RB_EVNT_HDR_SIZE;
+        if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT) {
+                event->type_len = 0;
+                event->array[0] = length;
+        } else
+                event->type_len = DIV_ROUND_UP(length, RB_ALIGNMENT);
 }
 
 /*
@@ -1823,10 +1879,13 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
         local_sub(length, &tail_page->write);
 }
 
-static struct ring_buffer_event *
+/*
+ * This is the slow path, force gcc not to inline it.
+ */
+static noinline struct ring_buffer_event *
 rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
              unsigned long length, unsigned long tail,
-             struct buffer_page *tail_page, u64 *ts)
+             struct buffer_page *tail_page, u64 ts)
 {
         struct buffer_page *commit_page = cpu_buffer->commit_page;
         struct ring_buffer *buffer = cpu_buffer->buffer;
@@ -1909,8 +1968,8 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
                  * Nested commits always have zero deltas, so
                  * just reread the time stamp
                  */
-                *ts = rb_time_stamp(buffer);
-                next_page->page->time_stamp = *ts;
+                ts = rb_time_stamp(buffer);
+                next_page->page->time_stamp = ts;
         }
 
  out_again:
@@ -1929,12 +1988,21 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
 
 static struct ring_buffer_event *
 __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
-                  unsigned type, unsigned long length, u64 *ts)
+                  unsigned long length, u64 ts,
+                  u64 delta, int add_timestamp)
 {
         struct buffer_page *tail_page;
         struct ring_buffer_event *event;
         unsigned long tail, write;
 
+        /*
+         * If the time delta since the last event is too big to
+         * hold in the time field of the event, then we append a
+         * TIME EXTEND event ahead of the data event.
+         */
+        if (unlikely(add_timestamp))
+                length += RB_LEN_TIME_EXTEND;
+
         tail_page = cpu_buffer->tail_page;
         write = local_add_return(length, &tail_page->write);
 
@@ -1943,7 +2011,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
         tail = write - length;
 
         /* See if we shot pass the end of this buffer page */
-        if (write > BUF_PAGE_SIZE)
+        if (unlikely(write > BUF_PAGE_SIZE))
                 return rb_move_tail(cpu_buffer, length, tail,
                                     tail_page, ts);
 
@@ -1951,18 +2019,16 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 
         event = __rb_page_index(tail_page, tail);
         kmemcheck_annotate_bitfield(event, bitfield);
-        rb_update_event(event, type, length);
+        rb_update_event(cpu_buffer, event, length, add_timestamp, delta);
 
-        /* The passed in type is zero for DATA */
-        if (likely(!type))
-                local_inc(&tail_page->entries);
+        local_inc(&tail_page->entries);
 
         /*
          * If this is the first commit on the page, then update
          * its timestamp.
          */
         if (!tail)
-                tail_page->page->time_stamp = *ts;
+                tail_page->page->time_stamp = ts;
 
         return event;
 }
@@ -1977,7 +2043,7 @@ rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
         unsigned long addr;
 
         new_index = rb_event_index(event);
-        old_index = new_index + rb_event_length(event);
+        old_index = new_index + rb_event_ts_length(event);
         addr = (unsigned long)event;
         addr &= PAGE_MASK;
 
@@ -2003,76 +2069,13 @@ rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
         return 0;
 }
 
-static int
-rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
-                  u64 *ts, u64 *delta)
-{
-        struct ring_buffer_event *event;
-        int ret;
-
-        WARN_ONCE(*delta > (1ULL << 59),
-                  KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n",
-                  (unsigned long long)*delta,
-                  (unsigned long long)*ts,
-                  (unsigned long long)cpu_buffer->write_stamp);
-
-        /*
-         * The delta is too big, we to add a
-         * new timestamp.
-         */
-        event = __rb_reserve_next(cpu_buffer,
-                                  RINGBUF_TYPE_TIME_EXTEND,
-                                  RB_LEN_TIME_EXTEND,
-                                  ts);
-        if (!event)
-                return -EBUSY;
-
-        if (PTR_ERR(event) == -EAGAIN)
-                return -EAGAIN;
-
-        /* Only a commited time event can update the write stamp */
-        if (rb_event_is_commit(cpu_buffer, event)) {
-                /*
-                 * If this is the first on the page, then it was
-                 * updated with the page itself. Try to discard it
-                 * and if we can't just make it zero.
-                 */
-                if (rb_event_index(event)) {
-                        event->time_delta = *delta & TS_MASK;
-                        event->array[0] = *delta >> TS_SHIFT;
-                } else {
-                        /* try to discard, since we do not need this */
-                        if (!rb_try_to_discard(cpu_buffer, event)) {
-                                /* nope, just zero it */
-                                event->time_delta = 0;
-                                event->array[0] = 0;
-                        }
-                }
-                cpu_buffer->write_stamp = *ts;
-                /* let the caller know this was the commit */
-                ret = 1;
-        } else {
-                /* Try to discard the event */
-                if (!rb_try_to_discard(cpu_buffer, event)) {
-                        /* Darn, this is just wasted space */
-                        event->time_delta = 0;
-                        event->array[0] = 0;
-                }
-                ret = 0;
-        }
-
-        *delta = 0;
-
-        return ret;
-}
-
 static void rb_start_commit(struct ring_buffer_per_cpu *cpu_buffer)
 {
         local_inc(&cpu_buffer->committing);
         local_inc(&cpu_buffer->commits);
 }
 
-static void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer)
+static inline void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer)
 {
         unsigned long commits;
 
@@ -2110,9 +2113,10 @@ rb_reserve_next_event(struct ring_buffer *buffer,
                       unsigned long length)
 {
         struct ring_buffer_event *event;
-        u64 ts, delta = 0;
-        int commit = 0;
+        u64 ts, delta;
         int nr_loops = 0;
+        int add_timestamp;
+        u64 diff;
 
         rb_start_commit(cpu_buffer);
 
@@ -2133,6 +2137,9 @@ rb_reserve_next_event(struct ring_buffer *buffer,
 
         length = rb_calculate_event_length(length);
  again:
+        add_timestamp = 0;
+        delta = 0;
+
         /*
          * We allow for interrupts to reenter here and do a trace.
          * If one does, it will cause this original code to loop
@@ -2146,56 +2153,32 @@ rb_reserve_next_event(struct ring_buffer *buffer,
                 goto out_fail;
 
         ts = rb_time_stamp(cpu_buffer->buffer);
+        diff = ts - cpu_buffer->write_stamp;
 
-        /*
-         * Only the first commit can update the timestamp.
-         * Yes there is a race here. If an interrupt comes in
-         * just after the conditional and it traces too, then it
-         * will also check the deltas. More than one timestamp may
-         * also be made. But only the entry that did the actual
-         * commit will be something other than zero.
-         */
-        if (likely(cpu_buffer->tail_page == cpu_buffer->commit_page &&
-                   rb_page_write(cpu_buffer->tail_page) ==
-                   rb_commit_index(cpu_buffer))) {
-                u64 diff;
-
-                diff = ts - cpu_buffer->write_stamp;
-
-                /* make sure this diff is calculated here */
-                barrier();
-
-                /* Did the write stamp get updated already? */
-                if (unlikely(ts < cpu_buffer->write_stamp))
-                        goto get_event;
+        /* make sure this diff is calculated here */
+        barrier();
 
+        /* Did the write stamp get updated already? */
+        if (likely(ts >= cpu_buffer->write_stamp)) {
                 delta = diff;
                 if (unlikely(test_time_stamp(delta))) {
-
-                        commit = rb_add_time_stamp(cpu_buffer, &ts, &delta);
-                        if (commit == -EBUSY)
-                                goto out_fail;
-
-                        if (commit == -EAGAIN)
-                                goto again;
-
-                        RB_WARN_ON(cpu_buffer, commit < 0);
+                        WARN_ONCE(delta > (1ULL << 59),
+                                  KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n",
+                                  (unsigned long long)delta,
+                                  (unsigned long long)ts,
+                                  (unsigned long long)cpu_buffer->write_stamp);
+                        add_timestamp = 1;
                 }
         }
 
- get_event:
-        event = __rb_reserve_next(cpu_buffer, 0, length, &ts);
+        event = __rb_reserve_next(cpu_buffer, length, ts,
+                                  delta, add_timestamp);
         if (unlikely(PTR_ERR(event) == -EAGAIN))
                 goto again;
 
         if (!event)
                 goto out_fail;
 
-        if (!rb_event_is_commit(cpu_buffer, event))
-                delta = 0;
-
-        event->time_delta = delta;
-
         return event;
 
  out_fail:
@@ -2207,13 +2190,9 @@ rb_reserve_next_event(struct ring_buffer *buffer,
 
 #define TRACE_RECURSIVE_DEPTH 16
 
-static int trace_recursive_lock(void)
+/* Keep this code out of the fast path cache */
+static noinline void trace_recursive_fail(void)
 {
-        current->trace_recursion++;
-
-        if (likely(current->trace_recursion < TRACE_RECURSIVE_DEPTH))
-                return 0;
-
         /* Disable all tracing before we do anything else */
         tracing_off_permanent();
 
@@ -2225,10 +2204,21 @@ static int trace_recursive_lock(void)
                     in_nmi());
 
         WARN_ON_ONCE(1);
+}
+
+static inline int trace_recursive_lock(void)
+{
+        current->trace_recursion++;
+
+        if (likely(current->trace_recursion < TRACE_RECURSIVE_DEPTH))
+                return 0;
+
+        trace_recursive_fail();
+
         return -1;
 }
 
-static void trace_recursive_unlock(void)
+static inline void trace_recursive_unlock(void)
 {
         WARN_ON_ONCE(!current->trace_recursion);
 
@@ -2308,12 +2298,28 @@ static void
 rb_update_write_stamp(struct ring_buffer_per_cpu *cpu_buffer,
                       struct ring_buffer_event *event)
 {
+        u64 delta;
+
         /*
          * The event first in the commit queue updates the
          * time stamp.
          */
-        if (rb_event_is_commit(cpu_buffer, event))
-                cpu_buffer->write_stamp += event->time_delta;
+        if (rb_event_is_commit(cpu_buffer, event)) {
+                /*
+                 * A commit event that is first on a page
+                 * updates the write timestamp with the page stamp
+                 */
+                if (!rb_event_index(event))
+                        cpu_buffer->write_stamp =
+                                cpu_buffer->commit_page->page->time_stamp;
+                else if (event->type_len == RINGBUF_TYPE_TIME_EXTEND) {
+                        delta = event->array[0];
+                        delta <<= TS_SHIFT;
+                        delta += event->time_delta;
+                        cpu_buffer->write_stamp += delta;
+                } else
+                        cpu_buffer->write_stamp += event->time_delta;
+        }
 }
 
 static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
@@ -2353,6 +2359,9 @@ EXPORT_SYMBOL_GPL(ring_buffer_unlock_commit);
 
 static inline void rb_event_discard(struct ring_buffer_event *event)
 {
+        if (event->type_len == RINGBUF_TYPE_TIME_EXTEND)
+                event = skip_time_extend(event);
+
         /* array[0] holds the actual length for the discarded event */
         event->array[0] = rb_event_data_length(event) - RB_EVNT_HDR_SIZE;
         event->type_len = RINGBUF_TYPE_PADDING;
@@ -3049,12 +3058,12 @@ rb_buffer_peek(struct ring_buffer_per_cpu *cpu_buffer, u64 *ts,
 
  again:
         /*
-         * We repeat when a timestamp is encountered. It is possible
-         * to get multiple timestamps from an interrupt entering just
-         * as one timestamp is about to be written, or from discarded
-         * commits. The most that we can have is the number on a single page.
+         * We repeat when a time extend is encountered.
+         * Since the time extend is always attached to a data event,
+         * we should never loop more than once.
+         * (We never hit the following condition more than twice).
          */
-        if (RB_WARN_ON(cpu_buffer, ++nr_loops > RB_TIMESTAMPS_PER_PAGE))
+        if (RB_WARN_ON(cpu_buffer, ++nr_loops > 2))
                 return NULL;
 
         reader = rb_get_reader_page(cpu_buffer);
@@ -3130,14 +3139,12 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
                 return NULL;
 
         /*
-         * We repeat when a timestamp is encountered.
-         * We can get multiple timestamps by nested interrupts or also
-         * if filtering is on (discarding commits). Since discarding
-         * commits can be frequent we can get a lot of timestamps.
-         * But we limit them by not adding timestamps if they begin
-         * at the start of a page.
+         * We repeat when a time extend is encountered.
+         * Since the time extend is always attached to a data event,
+         * we should never loop more than once.
+         * (We never hit the following condition more than twice).
          */
-        if (RB_WARN_ON(cpu_buffer, ++nr_loops > RB_TIMESTAMPS_PER_PAGE))
+        if (RB_WARN_ON(cpu_buffer, ++nr_loops > 2))
                 return NULL;
 
         if (rb_per_cpu_empty(cpu_buffer))
@@ -3835,7 +3842,8 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
                 if (len > (commit - read))
                         len = (commit - read);
 
-                size = rb_event_length(event);
+                /* Always keep the time extend and data together */
+                size = rb_event_ts_length(event);
 
                 if (len < size)
                         goto out_unlock;
@@ -3857,7 +3865,8 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
                                 break;
 
                         event = rb_reader_event(cpu_buffer);
-                        size = rb_event_length(event);
+                        /* Always keep the time extend and data together */
+                        size = rb_event_ts_length(event);
                 } while (len > size);
 
                 /* update bpage */
@@ -3974,6 +3983,7 @@ static const struct file_operations rb_simple_fops = {
         .open           = tracing_open_generic,
         .read           = rb_simple_read,
         .write          = rb_simple_write,
+        .llseek         = default_llseek,
 };
 
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 001bcd2ccf4..82d9b8106cd 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3996,13 +3996,9 @@ static void tracing_init_debugfs_percpu(long cpu)
 {
         struct dentry *d_percpu = tracing_dentry_percpu();
         struct dentry *d_cpu;
-        /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
-        char cpu_dir[7];
+        char cpu_dir[30]; /* 30 characters should be more than enough */
 
-        if (cpu > 999 || cpu < 0)
-                return;
-
-        sprintf(cpu_dir, "cpu%ld", cpu);
+        snprintf(cpu_dir, 30, "cpu%ld", cpu);
         d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
         if (!d_cpu) {
                 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 398c0e8b332..0725eeab193 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -932,6 +932,7 @@ static const struct file_operations ftrace_enable_fops = {
         .open = tracing_open_generic,
         .read = event_enable_read,
         .write = event_enable_write,
+        .llseek = default_llseek,
 };
 
 static const struct file_operations ftrace_event_format_fops = {
@@ -944,29 +945,34 @@ static const struct file_operations ftrace_event_format_fops = {
 static const struct file_operations ftrace_event_id_fops = {
         .open = tracing_open_generic,
         .read = event_id_read,
+        .llseek = default_llseek,
 };
 
 static const struct file_operations ftrace_event_filter_fops = {
         .open = tracing_open_generic,
         .read = event_filter_read,
         .write = event_filter_write,
+        .llseek = default_llseek,
 };
 
 static const struct file_operations ftrace_subsystem_filter_fops = {
         .open = tracing_open_generic,
         .read = subsystem_filter_read,
         .write = subsystem_filter_write,
+        .llseek = default_llseek,
 };
 
 static const struct file_operations ftrace_system_enable_fops = {
         .open = tracing_open_generic,
         .read = system_enable_read,
         .write = system_enable_write,
+        .llseek = default_llseek,
 };
 
 static const struct file_operations ftrace_show_header_fops = {
         .open = tracing_open_generic,
         .read = show_header,
+        .llseek = default_llseek,
 };
 
 static struct dentry *event_trace_events_dir(void)
diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c
index 7b8ecd751d9..3c5c5dfea0b 100644
--- a/kernel/trace/trace_kdb.c
+++ b/kernel/trace/trace_kdb.c
@@ -13,7 +13,6 @@
 #include <linux/kdb.h>
 #include <linux/ftrace.h>
 
-#include "../debug/kdb/kdb_private.h"
 #include "trace.h"
 #include "trace_output.h"
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 544301d29de..2dec9bcde8b 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -31,7 +31,6 @@
 #include <linux/perf_event.h>
 #include <linux/stringify.h>
 #include <linux/limits.h>
-#include <linux/uaccess.h>
 #include <asm/bitsperlong.h>
 
 #include "trace.h"
@@ -648,7 +647,7 @@ static int register_trace_probe(struct trace_probe *tp)
         }
         ret = register_probe_event(tp);
         if (ret) {
-                pr_warning("Faild to register probe event(%d)\n", ret);
+                pr_warning("Failed to register probe event(%d)\n", ret);
                 goto end;
         }
 
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index a6b7e0e0f3e..4c5dead0c23 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -195,6 +195,7 @@ static const struct file_operations stack_max_size_fops = {
         .open           = tracing_open_generic,
         .read           = stack_max_size_read,
         .write          = stack_max_size_write,
+        .llseek         = default_llseek,
 };
 
 static void *