Merge tag 'spi-v4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

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

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dade4c9..37824d9 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4123,6 +4123,30 @@ static const char readme_msg[] =
        "\t\t\t  traces\n"
 #endif
 #endif /* CONFIG_STACK_TRACER */
+#ifdef CONFIG_KPROBE_EVENT
+       "  kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
+       "\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#ifdef CONFIG_UPROBE_EVENT
+       "  uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"
+       "\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#if defined(CONFIG_KPROBE_EVENT) || defined(CONFIG_UPROBE_EVENT)
+       "\t  accepts: event-definitions (one definition per line)\n"
+       "\t   Format: p|r[:[<group>/]<event>] <place> [<args>]\n"
+       "\t           -:[<group>/]<event>\n"
+#ifdef CONFIG_KPROBE_EVENT
+       "\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
+#endif
+#ifdef CONFIG_UPROBE_EVENT
+       "\t    place: <path>:<offset>\n"
+#endif
+       "\t     args: <name>=fetcharg[:type]\n"
+       "\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
+       "\t           $stack<index>, $stack, $retval, $comm\n"
+       "\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string,\n"
+       "\t           b<bit-width>@<bit-offset>/<container-size>\n"
+#endif
        "  events/\t\t- Directory containing all trace event subsystems:\n"
        "      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
        "  events/<system>/\t- Directory containing all trace events for <system>:\n"
@@ -5124,19 +5148,20 @@ 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 +6188,6 @@ 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 +6197,9 @@ 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 +6257,21 @@ 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;