On Mon, 17 Nov 2014 21:44:11 -0500
Steven Rostedt <rost...@goodmis.org> wrote:

> On Tue, 18 Nov 2014 09:49:12 +0900
> Namhyung Kim <namhy...@kernel.org> wrote:
> 

> > > - ret = trace_seq_printf(s, "%s(", entry->name);
> > > - if (!ret)
> > > -         return TRACE_TYPE_PARTIAL_LINE;
> > > + trace_seq_printf(s, "%s(", entry->name);
> > >  
> > >   for (i = 0; i < entry->nb_args; i++) {
> > 
> >             if (trace_seq_has_overflowed())
> >                     goto end;
> > ?
> 
> Yeah, I guess I can do that.
> 

Here's the update:

-- Steve

>From 17845179b46f3e8b849d06a9a0069fd0a085e666 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rost...@goodmis.org>
Date: Wed, 12 Nov 2014 17:41:33 -0500
Subject: [PATCH] tracing: Do not use return values of trace_seq_printf() in
 syscall tracing

The functions trace_seq_printf() and friends will not be returning values
soon and will be void functions. To know if they succeeded or not, the
functions trace_seq_has_overflowed() and trace_handle_return() should be
used instead.

Reviewed-by: Petr Mladek <pmla...@suse.cz>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
 kernel/trace/trace_syscalls.c | 47 +++++++++++++++++--------------------------
 1 file changed, 19 insertions(+), 28 deletions(-)

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 4dc8b79c5f75..a72f3d8d813e 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -114,7 +114,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
        struct trace_entry *ent = iter->ent;
        struct syscall_trace_enter *trace;
        struct syscall_metadata *entry;
-       int i, ret, syscall;
+       int i, syscall;
 
        trace = (typeof(trace))ent;
        syscall = trace->nr;
@@ -128,35 +128,28 @@ print_syscall_enter(struct trace_iterator *iter, int 
flags,
                goto end;
        }
 
-       ret = trace_seq_printf(s, "%s(", entry->name);
-       if (!ret)
-               return TRACE_TYPE_PARTIAL_LINE;
+       trace_seq_printf(s, "%s(", entry->name);
 
        for (i = 0; i < entry->nb_args; i++) {
+
+               if (trace_seq_has_overflowed(s))
+                       goto end;
+
                /* parameter types */
-               if (trace_flags & TRACE_ITER_VERBOSE) {
-                       ret = trace_seq_printf(s, "%s ", entry->types[i]);
-                       if (!ret)
-                               return TRACE_TYPE_PARTIAL_LINE;
-               }
+               if (trace_flags & TRACE_ITER_VERBOSE)
+                       trace_seq_printf(s, "%s ", entry->types[i]);
+
                /* parameter values */
-               ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
-                                      trace->args[i],
-                                      i == entry->nb_args - 1 ? "" : ", ");
-               if (!ret)
-                       return TRACE_TYPE_PARTIAL_LINE;
+               trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+                                trace->args[i],
+                                i == entry->nb_args - 1 ? "" : ", ");
        }
 
-       ret = trace_seq_putc(s, ')');
-       if (!ret)
-               return TRACE_TYPE_PARTIAL_LINE;
-
+       trace_seq_putc(s, ')');
 end:
-       ret =  trace_seq_putc(s, '\n');
-       if (!ret)
-               return TRACE_TYPE_PARTIAL_LINE;
+       trace_seq_putc(s, '\n');
 
-       return TRACE_TYPE_HANDLED;
+       return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -168,7 +161,6 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
        struct syscall_trace_exit *trace;
        int syscall;
        struct syscall_metadata *entry;
-       int ret;
 
        trace = (typeof(trace))ent;
        syscall = trace->nr;
@@ -176,7 +168,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 
        if (!entry) {
                trace_seq_putc(s, '\n');
-               return TRACE_TYPE_HANDLED;
+               goto out;
        }
 
        if (entry->exit_event->event.type != ent->type) {
@@ -184,12 +176,11 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
                return TRACE_TYPE_UNHANDLED;
        }
 
-       ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+       trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
                                trace->ret);
-       if (!ret)
-               return TRACE_TYPE_PARTIAL_LINE;
 
-       return TRACE_TYPE_HANDLED;
+ out:
+       return trace_handle_return(s);
 }
 
 extern char *__bad_type_size(void);
-- 
1.8.1.4


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