[PATCH 48] introduce ptrace_lookup_engine()

[Oleg Nesterov]

The multi-line utrace_attach_task(a lot of args) looks really annoing,
add the trivial helper, ptrace_lookup_engine(tracee).

---

 kernel/ptrace.c |   32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

--- PU/kernel/ptrace.c~48_PTRACE_LOOKUP_ENGINE  2009-09-17 20:13:24.000000000 
+0200
+++ PU/kernel/ptrace.c  2009-09-17 20:35:09.000000000 +0200
@@ -98,13 +98,17 @@ static const struct utrace_engine_ops pt
 static int ptrace_attach_task(struct task_struct *tracee, int options);
 static void ptrace_abort_attach(struct task_struct *tracee);
 
+static struct utrace_engine *ptrace_lookup_engine(struct task_struct *tracee)
+{
+       return utrace_attach_task(tracee, UTRACE_ATTACH_MATCH_OPS,
+                                       &ptrace_utrace_ops, NULL);
+}
+
 static void ptrace_detach_task(struct task_struct *child, int sig)
 {
-       struct utrace_engine *engine;
+       struct utrace_engine *engine = ptrace_lookup_engine(child);
        int ret;
 
-       engine = utrace_attach_task(child, UTRACE_ATTACH_MATCH_OPS,
-                                   &ptrace_utrace_ops, NULL);
        if (unlikely(IS_ERR(engine)))
                return;
 
@@ -493,8 +497,7 @@ int ptrace_check_attach(struct task_stru
        if (child->parent != current)
                return -ESRCH;
 
-       engine = utrace_attach_task(child, UTRACE_ATTACH_MATCH_OPS,
-                                   &ptrace_utrace_ops, NULL);
+       engine = ptrace_lookup_engine(child);
        if (IS_ERR(engine))
                return -ESRCH;
 
@@ -805,10 +808,8 @@ int ptrace_writedata(struct task_struct 
 
 static int ptrace_set_options(struct task_struct *child, long data)
 {
-       struct utrace_engine *engine;
+       struct utrace_engine *engine = ptrace_lookup_engine(child);
 
-       engine = utrace_attach_task(child, UTRACE_ATTACH_MATCH_OPS,
-                                       &ptrace_utrace_ops, NULL);
        if (likely(!IS_ERR(engine))) {
                __ptrace_set_options(child, engine, data & PTRACE_O_MASK);
                utrace_engine_put(engine);
@@ -819,8 +820,7 @@ static int ptrace_set_options(struct tas
 
 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
 {
-       struct utrace_engine *engine = utrace_attach_task(child, 
UTRACE_ATTACH_MATCH_OPS,
-                                                               
&ptrace_utrace_ops, NULL);
+       struct utrace_engine *engine = ptrace_lookup_engine(child);
        unsigned long flags;
        int error = -ESRCH;
 
@@ -842,8 +842,7 @@ static int ptrace_getsiginfo(struct task
 
 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
 {
-       struct utrace_engine *engine = utrace_attach_task(child, 
UTRACE_ATTACH_MATCH_OPS,
-                                                               
&ptrace_utrace_ops, NULL);
+       struct utrace_engine *engine = ptrace_lookup_engine(child);
        unsigned long flags;
        int error = -ESRCH;
 
@@ -902,11 +901,9 @@ static void do_ptrace_notify_stop(struct
 
 void ptrace_notify_stop(struct task_struct *tracee)
 {
-       struct utrace_engine *engine;
+       struct utrace_engine *engine = ptrace_lookup_engine(tracee);
        struct ptrace_context *context;
 
-       engine = utrace_attach_task(tracee, UTRACE_ATTACH_MATCH_OPS,
-                                   &ptrace_utrace_ops, NULL);
        if (IS_ERR(engine)) {
                // XXX: temporary check, wrong with mutlitracing
                WARN_ON(tracee->state != TASK_RUNNING);
@@ -914,10 +911,8 @@ void ptrace_notify_stop(struct task_stru
        }
 
        context = ptrace_context(engine);
-
        if (WARN_ON(ev_empty(context)))
                return;
-
        do_ptrace_notify_stop(context, tracee);
 }
 
@@ -981,8 +976,7 @@ static int ptrace_resume(struct task_str
        if (!valid_signal(data))
                return -EIO;
 
-       engine = utrace_attach_task(child, UTRACE_ATTACH_MATCH_OPS,
-                                   &ptrace_utrace_ops, NULL);
+       engine = ptrace_lookup_engine(child);
        if (IS_ERR(engine))
                return -ESRCH;