ftrace: pipe fixes

Some fixes for better output with the trace pipe.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 7 insertions, 8 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 70f94fa92c10..c56fc5e60133 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -770,11 +770,6 @@ trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
 
         array = page_address(page);
 
-        /* Still possible to catch up to the tail */
-        if (iter->next_idx[cpu] && array == data->trace_tail &&
-            iter->next_page_idx[cpu] == data->trace_tail_idx)
-                return NULL;
-
         WARN_ON(iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE);
         return &array[iter->next_page_idx[cpu]];
 }
@@ -1921,7 +1916,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
         struct trace_iterator *iter = filp->private_data;
         struct trace_array_cpu *data;
         static cpumask_t mask;
-        struct trace_entry *entry;
         static int start;
         unsigned long flags;
         int read = 0;
@@ -2013,10 +2007,15 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
                 cpu_set(cpu, mask);
         }
 
-        while ((entry = find_next_entry_inc(iter)) != NULL) {
+        while (find_next_entry_inc(iter) != NULL) {
+                int len = iter->seq.len;
+
                 ret = print_trace_line(iter);
-                if (!ret)
+                if (!ret) {
+                        /* don't print partial lines */
+                        iter->seq.len = len;
                         break;
+                }
 
                 trace_consume(iter);