tracing: fix typos in comments
[pandora-kernel.git] / kernel / trace / trace.c
index 5822ff4..d7c175a 100644 (file)
@@ -31,6 +31,7 @@
 #include <linux/fs.h>
 #include <linux/kprobes.h>
 #include <linux/writeback.h>
+#include <linux/splice.h>
 
 #include <linux/stacktrace.h>
 #include <linux/ring_buffer.h>
@@ -364,6 +365,25 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
        return cnt;
 }
 
+ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
+{
+       int len;
+       void *ret;
+
+       if (s->len <= s->readpos)
+               return -EBUSY;
+
+       len = s->len - s->readpos;
+       if (cnt > len)
+               cnt = len;
+       ret = memcpy(buf, s->buffer + s->readpos, cnt);
+       if (!ret)
+               return -EFAULT;
+
+       s->readpos += len;
+       return cnt;
+}
+
 static void
 trace_print_seq(struct seq_file *m, struct trace_seq *s)
 {
@@ -522,23 +542,24 @@ int register_tracer(struct tracer *type)
        tracing_selftest_running = false;
        mutex_unlock(&trace_types_lock);
 
-       if (!ret && default_bootup_tracer) {
-               if (!strncmp(default_bootup_tracer, type->name,
-                            BOOTUP_TRACER_SIZE)) {
-                       printk(KERN_INFO "Starting tracer '%s'\n",
-                              type->name);
-                       /* Do we want this tracer to start on bootup? */
-                       tracing_set_tracer(type->name);
-                       default_bootup_tracer = NULL;
-                       /* disable other selftests, since this will break it. */
-                       tracing_selftest_disabled = 1;
+       if (ret || !default_bootup_tracer)
+               goto out_unlock;
+
+       if (strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE))
+               goto out_unlock;
+
+       printk(KERN_INFO "Starting tracer '%s'\n", type->name);
+       /* Do we want this tracer to start on bootup? */
+       tracing_set_tracer(type->name);
+       default_bootup_tracer = NULL;
+       /* disable other selftests, since this will break it. */
+       tracing_selftest_disabled = 1;
 #ifdef CONFIG_FTRACE_STARTUP_TEST
-                       printk(KERN_INFO "Disabling FTRACE selftests due"
-                              " to running tracer '%s'\n", type->name);
+       printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
+              type->name);
 #endif
-               }
-       }
 
+ out_unlock:
        lock_kernel();
        return ret;
 }
@@ -558,6 +579,15 @@ void unregister_tracer(struct tracer *type)
 
  found:
        *t = (*t)->next;
+
+       if (type == current_trace && tracer_enabled) {
+               tracer_enabled = 0;
+               tracing_stop();
+               if (current_trace->stop)
+                       current_trace->stop(&global_trace);
+               current_trace = &nop_trace;
+       }
+
        if (strlen(type->name) != max_tracer_type_len)
                goto out;
 
@@ -775,78 +805,100 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
                (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
 }
 
+struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
+                                                   unsigned char type,
+                                                   unsigned long len,
+                                                   unsigned long flags, int pc)
+{
+       struct ring_buffer_event *event;
+
+       event = ring_buffer_lock_reserve(tr->buffer, len);
+       if (event != NULL) {
+               struct trace_entry *ent = ring_buffer_event_data(event);
+
+               tracing_generic_entry_update(ent, flags, pc);
+               ent->type = type;
+       }
+
+       return event;
+}
+static void ftrace_trace_stack(struct trace_array *tr,
+                              unsigned long flags, int skip, int pc);
+static void ftrace_trace_userstack(struct trace_array *tr,
+                                  unsigned long flags, int pc);
+
+void trace_buffer_unlock_commit(struct trace_array *tr,
+                               struct ring_buffer_event *event,
+                               unsigned long flags, int pc)
+{
+       ring_buffer_unlock_commit(tr->buffer, event);
+
+       ftrace_trace_stack(tr, flags, 6, pc);
+       ftrace_trace_userstack(tr, flags, pc);
+       trace_wake_up();
+}
+
 void
-trace_function(struct trace_array *tr, struct trace_array_cpu *data,
+trace_function(struct trace_array *tr,
               unsigned long ip, unsigned long parent_ip, unsigned long flags,
               int pc)
 {
        struct ring_buffer_event *event;
        struct ftrace_entry *entry;
-       unsigned long irq_flags;
 
        /* If we are reading the ring buffer, don't trace */
        if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                return;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
-                                        &irq_flags);
+       event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry),
+                                         flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_FN;
        entry->ip                       = ip;
        entry->parent_ip                = parent_ip;
-       ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+       ring_buffer_unlock_commit(tr->buffer, event);
 }
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static void __trace_graph_entry(struct trace_array *tr,
-                               struct trace_array_cpu *data,
                                struct ftrace_graph_ent *trace,
                                unsigned long flags,
                                int pc)
 {
        struct ring_buffer_event *event;
        struct ftrace_graph_ent_entry *entry;
-       unsigned long irq_flags;
 
        if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                return;
 
-       event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry),
-                                        &irq_flags);
+       event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_ENT,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_GRAPH_ENT;
        entry->graph_ent                        = *trace;
-       ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags);
+       ring_buffer_unlock_commit(global_trace.buffer, event);
 }
 
 static void __trace_graph_return(struct trace_array *tr,
-                               struct trace_array_cpu *data,
                                struct ftrace_graph_ret *trace,
                                unsigned long flags,
                                int pc)
 {
        struct ring_buffer_event *event;
        struct ftrace_graph_ret_entry *entry;
-       unsigned long irq_flags;
 
        if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
                return;
 
-       event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry),
-                                        &irq_flags);
+       event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_RET,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_GRAPH_RET;
        entry->ret                              = *trace;
-       ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags);
+       ring_buffer_unlock_commit(global_trace.buffer, event);
 }
 #endif
 
@@ -856,11 +908,10 @@ ftrace(struct trace_array *tr, struct trace_array_cpu *data,
        int pc)
 {
        if (likely(!atomic_read(&data->disabled)))
-               trace_function(tr, data, ip, parent_ip, flags, pc);
+               trace_function(tr, ip, parent_ip, flags, pc);
 }
 
 static void __ftrace_trace_stack(struct trace_array *tr,
-                                struct trace_array_cpu *data,
                                 unsigned long flags,
                                 int skip, int pc)
 {
@@ -868,16 +919,12 @@ static void __ftrace_trace_stack(struct trace_array *tr,
        struct ring_buffer_event *event;
        struct stack_entry *entry;
        struct stack_trace trace;
-       unsigned long irq_flags;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
-                                        &irq_flags);
+       event = trace_buffer_lock_reserve(tr, TRACE_STACK,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type         = TRACE_STACK;
-
        memset(&entry->caller, 0, sizeof(entry->caller));
 
        trace.nr_entries        = 0;
@@ -886,49 +933,43 @@ static void __ftrace_trace_stack(struct trace_array *tr,
        trace.entries           = entry->caller;
 
        save_stack_trace(&trace);
-       ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+       ring_buffer_unlock_commit(tr->buffer, event);
 #endif
 }
 
 static void ftrace_trace_stack(struct trace_array *tr,
-                              struct trace_array_cpu *data,
                               unsigned long flags,
                               int skip, int pc)
 {
        if (!(trace_flags & TRACE_ITER_STACKTRACE))
                return;
 
-       __ftrace_trace_stack(tr, data, flags, skip, pc);
+       __ftrace_trace_stack(tr, flags, skip, pc);
 }
 
 void __trace_stack(struct trace_array *tr,
-                  struct trace_array_cpu *data,
                   unsigned long flags,
                   int skip, int pc)
 {
-       __ftrace_trace_stack(tr, data, flags, skip, pc);
+       __ftrace_trace_stack(tr, flags, skip, pc);
 }
 
 static void ftrace_trace_userstack(struct trace_array *tr,
-                  struct trace_array_cpu *data,
-                  unsigned long flags, int pc)
+                                  unsigned long flags, int pc)
 {
 #ifdef CONFIG_STACKTRACE
        struct ring_buffer_event *event;
        struct userstack_entry *entry;
        struct stack_trace trace;
-       unsigned long irq_flags;
 
        if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
                return;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
-                                        &irq_flags);
+       event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type         = TRACE_USER_STACK;
 
        memset(&entry->caller, 0, sizeof(entry->caller));
 
@@ -938,70 +979,56 @@ static void ftrace_trace_userstack(struct trace_array *tr,
        trace.entries           = entry->caller;
 
        save_stack_trace_user(&trace);
-       ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+       ring_buffer_unlock_commit(tr->buffer, event);
 #endif
 }
 
-void __trace_userstack(struct trace_array *tr,
-                  struct trace_array_cpu *data,
-                  unsigned long flags)
+void __trace_userstack(struct trace_array *tr, unsigned long flags)
 {
-       ftrace_trace_userstack(tr, data, flags, preempt_count());
+       ftrace_trace_userstack(tr, flags, preempt_count());
 }
 
 static void
-ftrace_trace_special(void *__tr, void *__data,
+ftrace_trace_special(void *__tr,
                     unsigned long arg1, unsigned long arg2, unsigned long arg3,
                     int pc)
 {
        struct ring_buffer_event *event;
-       struct trace_array_cpu *data = __data;
        struct trace_array *tr = __tr;
        struct special_entry *entry;
-       unsigned long irq_flags;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
-                                        &irq_flags);
+       event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL,
+                                         sizeof(*entry), 0, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, 0, pc);
-       entry->ent.type                 = TRACE_SPECIAL;
        entry->arg1                     = arg1;
        entry->arg2                     = arg2;
        entry->arg3                     = arg3;
-       ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
-       ftrace_trace_stack(tr, data, irq_flags, 4, pc);
-       ftrace_trace_userstack(tr, data, irq_flags, pc);
-
-       trace_wake_up();
+       trace_buffer_unlock_commit(tr, event, 0, pc);
 }
 
 void
 __trace_special(void *__tr, void *__data,
                unsigned long arg1, unsigned long arg2, unsigned long arg3)
 {
-       ftrace_trace_special(__tr, __data, arg1, arg2, arg3, preempt_count());
+       ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count());
 }
 
 void
 tracing_sched_switch_trace(struct trace_array *tr,
-                          struct trace_array_cpu *data,
                           struct task_struct *prev,
                           struct task_struct *next,
                           unsigned long flags, int pc)
 {
        struct ring_buffer_event *event;
        struct ctx_switch_entry *entry;
-       unsigned long irq_flags;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
-                                          &irq_flags);
+       event = trace_buffer_lock_reserve(tr, TRACE_CTX,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_CTX;
        entry->prev_pid                 = prev->pid;
        entry->prev_prio                = prev->prio;
        entry->prev_state               = prev->state;
@@ -1009,29 +1036,23 @@ tracing_sched_switch_trace(struct trace_array *tr,
        entry->next_prio                = next->prio;
        entry->next_state               = next->state;
        entry->next_cpu = task_cpu(next);
-       ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
-       ftrace_trace_stack(tr, data, flags, 5, pc);
-       ftrace_trace_userstack(tr, data, flags, pc);
+       trace_buffer_unlock_commit(tr, event, flags, pc);
 }
 
 void
 tracing_sched_wakeup_trace(struct trace_array *tr,
-                          struct trace_array_cpu *data,
                           struct task_struct *wakee,
                           struct task_struct *curr,
                           unsigned long flags, int pc)
 {
        struct ring_buffer_event *event;
        struct ctx_switch_entry *entry;
-       unsigned long irq_flags;
 
-       event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
-                                          &irq_flags);
+       event = trace_buffer_lock_reserve(tr, TRACE_WAKE,
+                                         sizeof(*entry), flags, pc);
        if (!event)
                return;
        entry   = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, flags, pc);
-       entry->ent.type                 = TRACE_WAKE;
        entry->prev_pid                 = curr->pid;
        entry->prev_prio                = curr->prio;
        entry->prev_state               = curr->state;
@@ -1039,11 +1060,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
        entry->next_prio                = wakee->prio;
        entry->next_state               = wakee->state;
        entry->next_cpu                 = task_cpu(wakee);
-       ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
-       ftrace_trace_stack(tr, data, flags, 6, pc);
-       ftrace_trace_userstack(tr, data, flags, pc);
-
-       trace_wake_up();
+       trace_buffer_unlock_commit(tr, event, flags, pc);
 }
 
 void
@@ -1064,7 +1081,7 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
        data = tr->data[cpu];
 
        if (likely(atomic_inc_return(&data->disabled) == 1))
-               ftrace_trace_special(tr, data, arg1, arg2, arg3, pc);
+               ftrace_trace_special(tr, arg1, arg2, arg3, pc);
 
        atomic_dec(&data->disabled);
        local_irq_restore(flags);
@@ -1092,7 +1109,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
        disabled = atomic_inc_return(&data->disabled);
        if (likely(disabled == 1)) {
                pc = preempt_count();
-               __trace_graph_entry(tr, data, trace, flags, pc);
+               __trace_graph_entry(tr, trace, flags, pc);
        }
        /* Only do the atomic if it is not already set */
        if (!test_tsk_trace_graph(current))
@@ -1118,7 +1135,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
        disabled = atomic_inc_return(&data->disabled);
        if (likely(disabled == 1)) {
                pc = preempt_count();
-               __trace_graph_return(tr, data, trace, flags, pc);
+               __trace_graph_return(tr, trace, flags, pc);
        }
        if (!trace->depth)
                clear_tsk_trace_graph(current);
@@ -1412,7 +1429,7 @@ static enum print_line_t print_lat_fmt(struct trace_iterator *iter)
                        goto partial;
        }
 
-       if (event && event->latency_trace)
+       if (event)
                return event->latency_trace(iter, sym_flags);
 
        if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
@@ -1441,7 +1458,7 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
                        goto partial;
        }
 
-       if (event && event->trace)
+       if (event)
                return event->trace(iter, sym_flags);
 
        if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
@@ -1467,7 +1484,7 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
        }
 
        event = ftrace_find_event(entry->type);
-       if (event && event->raw)
+       if (event)
                return event->raw(iter, 0);
 
        if (!trace_seq_printf(s, "%d ?\n", entry->type))
@@ -1494,8 +1511,8 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
        }
 
        event = ftrace_find_event(entry->type);
-       if (event && event->hex) {
-               int ret = event->hex(iter, 0);
+       if (event) {
+               enum print_line_t ret = event->hex(iter, 0);
                if (ret != TRACE_TYPE_HANDLED)
                        return ret;
        }
@@ -1531,15 +1548,12 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
 
        if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
                SEQ_PUT_FIELD_RET(s, entry->pid);
-               SEQ_PUT_FIELD_RET(s, entry->cpu);
+               SEQ_PUT_FIELD_RET(s, iter->cpu);
                SEQ_PUT_FIELD_RET(s, iter->ts);
        }
 
        event = ftrace_find_event(entry->type);
-       if (event && event->binary)
-               return event->binary(iter, 0);
-
-       return TRACE_TYPE_HANDLED;
+       return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED;
 }
 
 static int trace_empty(struct trace_iterator *iter)
@@ -1949,7 +1963,7 @@ tracing_trace_options_read(struct file *filp, char __user *ubuf,
        struct tracer_opt *trace_opts = current_trace->flags->opts;
 
 
-       /* calulate max size */
+       /* calculate max size */
        for (i = 0; trace_options[i]; i++) {
                len += strlen(trace_options[i]);
                len += 3; /* "no" and space */
@@ -2186,6 +2200,12 @@ tracing_set_trace_read(struct file *filp, char __user *ubuf,
        return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 
+int tracer_init(struct tracer *t, struct trace_array *tr)
+{
+       tracing_reset_online_cpus(tr);
+       return t->init(tr);
+}
+
 static int tracing_set_tracer(const char *buf)
 {
        struct trace_array *tr = &global_trace;
@@ -2210,7 +2230,7 @@ static int tracing_set_tracer(const char *buf)
 
        current_trace = t;
        if (t->init) {
-               ret = t->init(tr);
+               ret = tracer_init(t, tr);
                if (ret)
                        goto out;
        }
@@ -2368,37 +2388,15 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table)
        }
 }
 
-/*
- * Consumer reader.
- */
-static ssize_t
-tracing_read_pipe(struct file *filp, char __user *ubuf,
-                 size_t cnt, loff_t *ppos)
+/* Must be called with trace_types_lock mutex held. */
+static int tracing_wait_pipe(struct file *filp)
 {
        struct trace_iterator *iter = filp->private_data;
-       ssize_t sret;
-
-       /* return any leftover data */
-       sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
-       if (sret != -EBUSY)
-               return sret;
-
-       trace_seq_reset(&iter->seq);
-
-       mutex_lock(&trace_types_lock);
-       if (iter->trace->read) {
-               sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
-               if (sret)
-                       goto out;
-       }
 
-waitagain:
-       sret = 0;
        while (trace_empty(iter)) {
 
                if ((filp->f_flags & O_NONBLOCK)) {
-                       sret = -EAGAIN;
-                       goto out;
+                       return -EAGAIN;
                }
 
                /*
@@ -2423,12 +2421,11 @@ waitagain:
                iter->tr->waiter = NULL;
 
                if (signal_pending(current)) {
-                       sret = -EINTR;
-                       goto out;
+                       return -EINTR;
                }
 
                if (iter->trace != current_trace)
-                       goto out;
+                       return 0;
 
                /*
                 * We block until we read something and tracing is disabled.
@@ -2445,9 +2442,43 @@ waitagain:
                continue;
        }
 
+       return 1;
+}
+
+/*
+ * Consumer reader.
+ */
+static ssize_t
+tracing_read_pipe(struct file *filp, char __user *ubuf,
+                 size_t cnt, loff_t *ppos)
+{
+       struct trace_iterator *iter = filp->private_data;
+       ssize_t sret;
+
+       /* return any leftover data */
+       sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+       if (sret != -EBUSY)
+               return sret;
+
+       trace_seq_reset(&iter->seq);
+
+       mutex_lock(&trace_types_lock);
+       if (iter->trace->read) {
+               sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
+               if (sret)
+                       goto out;
+       }
+
+waitagain:
+       sret = tracing_wait_pipe(filp);
+       if (sret <= 0)
+               goto out;
+
        /* stop when tracing is finished */
-       if (trace_empty(iter))
+       if (trace_empty(iter)) {
+               sret = 0;
                goto out;
+       }
 
        if (cnt >= PAGE_SIZE)
                cnt = PAGE_SIZE - 1;
@@ -2468,8 +2499,8 @@ waitagain:
                        iter->seq.len = len;
                        break;
                }
-
-               trace_consume(iter);
+               if (ret != TRACE_TYPE_NO_CONSUME)
+                       trace_consume(iter);
 
                if (iter->seq.len >= cnt)
                        break;
@@ -2493,6 +2524,135 @@ out:
        return sret;
 }
 
+static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
+                                    struct pipe_buffer *buf)
+{
+       __free_page(buf->page);
+}
+
+static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
+                                    unsigned int idx)
+{
+       __free_page(spd->pages[idx]);
+}
+
+static struct pipe_buf_operations tracing_pipe_buf_ops = {
+       .can_merge              = 0,
+       .map                    = generic_pipe_buf_map,
+       .unmap                  = generic_pipe_buf_unmap,
+       .confirm                = generic_pipe_buf_confirm,
+       .release                = tracing_pipe_buf_release,
+       .steal                  = generic_pipe_buf_steal,
+       .get                    = generic_pipe_buf_get,
+};
+
+static size_t
+tracing_fill_pipe_page(struct page *pages, size_t rem,
+                       struct trace_iterator *iter)
+{
+       size_t count;
+       int ret;
+
+       /* Seq buffer is page-sized, exactly what we need. */
+       for (;;) {
+               count = iter->seq.len;
+               ret = print_trace_line(iter);
+               count = iter->seq.len - count;
+               if (rem < count) {
+                       rem = 0;
+                       iter->seq.len -= count;
+                       break;
+               }
+               if (ret == TRACE_TYPE_PARTIAL_LINE) {
+                       iter->seq.len -= count;
+                       break;
+               }
+
+               trace_consume(iter);
+               rem -= count;
+               if (!find_next_entry_inc(iter)) {
+                       rem = 0;
+                       iter->ent = NULL;
+                       break;
+               }
+       }
+
+       return rem;
+}
+
+static ssize_t tracing_splice_read_pipe(struct file *filp,
+                                       loff_t *ppos,
+                                       struct pipe_inode_info *pipe,
+                                       size_t len,
+                                       unsigned int flags)
+{
+       struct page *pages[PIPE_BUFFERS];
+       struct partial_page partial[PIPE_BUFFERS];
+       struct trace_iterator *iter = filp->private_data;
+       struct splice_pipe_desc spd = {
+               .pages          = pages,
+               .partial        = partial,
+               .nr_pages       = 0, /* This gets updated below. */
+               .flags          = flags,
+               .ops            = &tracing_pipe_buf_ops,
+               .spd_release    = tracing_spd_release_pipe,
+       };
+       ssize_t ret;
+       size_t rem;
+       unsigned int i;
+
+       mutex_lock(&trace_types_lock);
+
+       if (iter->trace->splice_read) {
+               ret = iter->trace->splice_read(iter, filp,
+                                              ppos, pipe, len, flags);
+               if (ret)
+                       goto out_err;
+       }
+
+       ret = tracing_wait_pipe(filp);
+       if (ret <= 0)
+               goto out_err;
+
+       if (!iter->ent && !find_next_entry_inc(iter)) {
+               ret = -EFAULT;
+               goto out_err;
+       }
+
+       /* Fill as many pages as possible. */
+       for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) {
+               pages[i] = alloc_page(GFP_KERNEL);
+               if (!pages[i])
+                       break;
+
+               rem = tracing_fill_pipe_page(pages[i], rem, iter);
+
+               /* Copy the data into the page, so we can start over. */
+               ret = trace_seq_to_buffer(&iter->seq,
+                                         page_address(pages[i]),
+                                         iter->seq.len);
+               if (ret < 0) {
+                       __free_page(pages[i]);
+                       break;
+               }
+               partial[i].offset = 0;
+               partial[i].len = iter->seq.len;
+
+               trace_seq_reset(&iter->seq);
+       }
+
+       mutex_unlock(&trace_types_lock);
+
+       spd.nr_pages = i;
+
+       return splice_to_pipe(pipe, &spd);
+
+out_err:
+       mutex_unlock(&trace_types_lock);
+
+       return ret;
+}
+
 static ssize_t
 tracing_entries_read(struct file *filp, char __user *ubuf,
                     size_t cnt, loff_t *ppos)
@@ -2656,6 +2816,7 @@ static struct file_operations tracing_pipe_fops = {
        .open           = tracing_open_pipe,
        .poll           = tracing_poll_pipe,
        .read           = tracing_read_pipe,
+       .splice_read    = tracing_splice_read_pipe,
        .release        = tracing_release_pipe,
 };
 
@@ -2854,18 +3015,16 @@ int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
        trace_buf[len] = 0;
 
        size = sizeof(*entry) + len + 1;
-       event = ring_buffer_lock_reserve(tr->buffer, size, &irq_flags);
+       event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
        if (!event)
                goto out_unlock;
        entry = ring_buffer_event_data(event);
-       tracing_generic_entry_update(&entry->ent, irq_flags, pc);
-       entry->ent.type                 = TRACE_PRINT;
        entry->ip                       = ip;
        entry->depth                    = depth;
 
        memcpy(&entry->buf, trace_buf, len);
        entry->buf[len] = 0;
-       ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+       ring_buffer_unlock_commit(tr->buffer, event);
 
  out_unlock:
        spin_unlock_irqrestore(&trace_buf_lock, irq_flags);