tracing: Use trace_seq instead of open code string appending

The filter code does open code string appending to produce an error message.
Instead it can be simplified by using trace_seq function helpers.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 819a13c3e13cfbdf062a45332b983ea85d805153..f42442cd423a8fd10bcd87fe814cc4c541ed3d25 100644 (file)
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -675,47 +675,36 @@ static int replace_filter_string(struct event_filter *filter,
        return 0;
 }
 
-static int append_filter_string(struct event_filter *filter,
-                               char *string)
-{
-       int newlen;
-       char *new_filter_string;
-
-       if (WARN_ON(!filter->filter_string))
-               return -EINVAL;
-       newlen = strlen(filter->filter_string) + strlen(string) + 1;
-       new_filter_string = kmalloc(newlen, GFP_KERNEL);
-       if (!new_filter_string)
-               return -ENOMEM;
-
-       strcpy(new_filter_string, filter->filter_string);
-       strcat(new_filter_string, string);
-       kfree(filter->filter_string);
-       filter->filter_string = new_filter_string;
-
-       return 0;
-}
-
 static void append_filter_err(struct filter_parse_state *ps,
                              struct event_filter *filter)
 {
+       struct trace_seq *s;
        int pos = ps->lasterr_pos;
-       char *buf, *pbuf;
+       char *buf;
+       int len;
 
-       buf = (char *)__get_free_page(GFP_KERNEL);
-       if (!buf)
+       if (WARN_ON(!filter->filter_string))
                return;
 
-       append_filter_string(filter, "\n");
-       memset(buf, ' ', PAGE_SIZE);
-       if (pos > PAGE_SIZE - 128)
-               pos = 0;
-       buf[pos] = '^';
-       pbuf = &buf[pos] + 1;
-
-       sprintf(pbuf, "\nparse_error: %s\n", err_text[ps->lasterr]);
-       append_filter_string(filter, buf);
-       free_page((unsigned long) buf);
+       s = kmalloc(sizeof(*s), GFP_KERNEL);
+       if (!s)
+               return;
+       trace_seq_init(s);
+
+       len = strlen(filter->filter_string);
+       if (pos > len)
+               len = pos;
+
+       trace_seq_puts(s, filter->filter_string);
+       trace_seq_printf(s, "\n%*s", pos, "^");
+       trace_seq_printf(s, "\nparse_error: %s\n", err_text[ps->lasterr]);
+       trace_seq_putc(s, 0);
+       buf = kmemdup_nul(s->buffer, s->seq.len, GFP_KERNEL);
+       if (buf) {
+               kfree(filter->filter_string);
+               filter->filter_string = buf;
+       }
+       kfree(s);
 }
 
 static inline struct event_filter *event_filter(struct trace_event_file *file)