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Subject[PATCH 1/2] signals: introduce do_send_sig_info() helper
Introduce do_send_sig_info() and convert group_send_sig_info(),
send_sig_info(), do_send_specific() to use this helper.

Hopefully it will have more users soon, it allows to specify
specific/group behaviour via "bool group" argument.

Shaves 80 bytes from .text.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
include/linux/signal.h | 2 +
kernel/signal.c | 56 +++++++++++++++++++++++--------------------------
2 files changed, 29 insertions(+), 29 deletions(-)
--- WAIT/include/linux/signal.h~1_HELPER 2009-06-11 14:16:46.000000000 +0200
+++ WAIT/include/linux/signal.h 2009-08-01 02:26:41.000000000 +0200
@@ -233,6 +233,8 @@ static inline int valid_signal(unsigned
}

extern int next_signal(struct sigpending *pending, sigset_t *mask);
+extern int do_send_sig_info(int sig, struct siginfo *info,
+ struct task_struct *p, bool group);
extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
extern long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig,
--- WAIT/kernel/signal.c~1_HELPER 2009-07-01 20:22:44.000000000 +0200
+++ WAIT/kernel/signal.c 2009-08-01 02:21:27.000000000 +0200
@@ -971,6 +971,20 @@ specific_send_sig_info(int sig, struct s
return send_signal(sig, info, t, 0);
}

+int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
+ bool group)
+{
+ unsigned long flags;
+ int ret = -ESRCH;
+
+ if (lock_task_sighand(p, &flags)) {
+ ret = send_signal(sig, info, p, group);
+ unlock_task_sighand(p, &flags);
+ }
+
+ return ret;
+}
+
/*
* Force a signal that the process can't ignore: if necessary
* we unblock the signal and change any SIG_IGN to SIG_DFL.
@@ -1068,18 +1082,10 @@ struct sighand_struct *lock_task_sighand
*/
int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
- unsigned long flags;
- int ret;
-
- ret = check_kill_permission(sig, info, p);
+ int ret = check_kill_permission(sig, info, p);

- if (!ret && sig) {
- ret = -ESRCH;
- if (lock_task_sighand(p, &flags)) {
- ret = __group_send_sig_info(sig, info, p);
- unlock_task_sighand(p, &flags);
- }
- }
+ if (!ret && sig)
+ ret = do_send_sig_info(sig, info, p, true);

return ret;
}
@@ -1224,15 +1230,9 @@ static int kill_something_info(int sig,
* These are for backward compatibility with the rest of the kernel source.
*/

-/*
- * The caller must ensure the task can't exit.
- */
int
send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
- int ret;
- unsigned long flags;
-
/*
* Make sure legacy kernel users don't send in bad values
* (normal paths check this in check_kill_permission).
@@ -1240,10 +1240,7 @@ send_sig_info(int sig, struct siginfo *i
if (!valid_signal(sig))
return -EINVAL;

- spin_lock_irqsave(&p->sighand->siglock, flags);
- ret = specific_send_sig_info(sig, info, p);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- return ret;
+ return do_send_sig_info(sig, info, p, false);
}

#define __si_special(priv) \
@@ -2281,7 +2278,6 @@ static int
do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
{
struct task_struct *p;
- unsigned long flags;
int error = -ESRCH;

rcu_read_lock();
@@ -2291,14 +2287,16 @@ do_send_specific(pid_t tgid, pid_t pid,
/*
* The null signal is a permissions and process existence
* probe. No signal is actually delivered.
- *
- * If lock_task_sighand() fails we pretend the task dies
- * after receiving the signal. The window is tiny, and the
- * signal is private anyway.
*/
- if (!error && sig && lock_task_sighand(p, &flags)) {
- error = specific_send_sig_info(sig, info, p);
- unlock_task_sighand(p, &flags);
+ if (!error && sig) {
+ error = do_send_sig_info(sig, info, p, false);
+ /*
+ * If lock_task_sighand() failed we pretend the task
+ * dies after receiving the signal. The window is tiny,
+ * and the signal is private anyway.
+ */
+ if (unlikely(error == -ESRCH))
+ error = 0;
}
}
rcu_read_unlock();


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