Merge tag 'trace-v4.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...

[cascardo/linux.git] / kernel / trace / trace.c

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dade4c9..7bc5676 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5124,19 +5124,20 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
        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_init(&iter->seq);
-
        /*
         * Avoid more than one consumer on a single file descriptor
         * This is just a matter of traces coherency, the ring buffer itself
         * is protected.
         */
        mutex_lock(&iter->mutex);
+
+       /* return any leftover data */
+       sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+       if (sret != -EBUSY)
+               goto out;
+
+       trace_seq_init(&iter->seq);
+
        if (iter->trace->read) {
                sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
                if (sret)
@@ -6163,9 +6164,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
                return -EBUSY;
 #endif
 
-       if (splice_grow_spd(pipe, &spd))
-               return -ENOMEM;
-
        if (*ppos & (PAGE_SIZE - 1))
                return -EINVAL;
 
@@ -6175,6 +6173,9 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
                len &= PAGE_MASK;
        }
 
+       if (splice_grow_spd(pipe, &spd))
+               return -ENOMEM;
+
  again:
        trace_access_lock(iter->cpu_file);
        entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
@@ -6232,19 +6233,21 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
        /* did we read anything? */
        if (!spd.nr_pages) {
                if (ret)
-                       return ret;
+                       goto out;
 
+               ret = -EAGAIN;
                if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
-                       return -EAGAIN;
+                       goto out;
 
                ret = wait_on_pipe(iter, true);
                if (ret)
-                       return ret;
+                       goto out;
 
                goto again;
        }
 
        ret = splice_to_pipe(pipe, &spd);
+out:
        splice_shrink_spd(&spd);
 
        return ret;