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Subject[PATCH RESEND2 06/11] signals: mv {dis,}allow_signal() from sched.h/exit.c to signal.[ch]
Move the declaration/definition of allow_signal/disallow_signal to
signal.h/signal.c. The new place is more logical and allows to use
the static helpers in signal.c (see the next changes).

While at it, make them return void and remove the valid_signal()
check. Nobody checks the returned value, and in-kernel users must
not pass the wrong signal number.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
include/linux/sched.h | 3 ---
include/linux/signal.h | 2 ++
kernel/exit.c | 39 ---------------------------------------
kernel/signal.c | 29 +++++++++++++++++++++++++++++
4 files changed, 31 insertions(+), 42 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index a04214f..82fe3da 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2360,9 +2360,6 @@ extern void flush_itimer_signals(void);

extern void do_group_exit(int);

-extern int allow_signal(int);
-extern int disallow_signal(int);
-
extern int do_execve(struct filename *,
const char __user * const __user *,
const char __user * const __user *);
diff --git a/include/linux/signal.h b/include/linux/signal.h
index ae744c3..ac83c59 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -284,6 +284,8 @@ extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
extern void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka, struct pt_regs *regs, int stepping);
extern void exit_signals(struct task_struct *tsk);
+extern void allow_signal(int);
+extern void disallow_signal(int);

/*
* Eventually that'll replace get_signal_to_deliver(); macro for now,
diff --git a/kernel/exit.c b/kernel/exit.c
index 6ed6a1d..ad7183a 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -313,45 +313,6 @@ kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
}
}

-/*
- * Let kernel threads use this to say that they allow a certain signal.
- * Must not be used if kthread was cloned with CLONE_SIGHAND.
- */
-int allow_signal(int sig)
-{
- if (!valid_signal(sig) || sig < 1)
- return -EINVAL;
-
- spin_lock_irq(&current->sighand->siglock);
- /* This is only needed for daemonize()'ed kthreads */
- sigdelset(&current->blocked, sig);
- /*
- * Kernel threads handle their own signals. Let the signal code
- * know it'll be handled, so that they don't get converted to
- * SIGKILL or just silently dropped.
- */
- current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
- recalc_sigpending();
- spin_unlock_irq(&current->sighand->siglock);
- return 0;
-}
-
-EXPORT_SYMBOL(allow_signal);
-
-int disallow_signal(int sig)
-{
- if (!valid_signal(sig) || sig < 1)
- return -EINVAL;
-
- spin_lock_irq(&current->sighand->siglock);
- current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
- recalc_sigpending();
- spin_unlock_irq(&current->sighand->siglock);
- return 0;
-}
-
-EXPORT_SYMBOL(disallow_signal);
-
#ifdef CONFIG_MM_OWNER
/*
* A task is exiting. If it owned this mm, find a new owner for the mm.
diff --git a/kernel/signal.c b/kernel/signal.c
index a58b0db..8a7ee44 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3065,6 +3065,35 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
}
#endif

+/*
+ * Let kernel threads use this to say that they allow a certain signal.
+ * Must not be used if kthread was cloned with CLONE_SIGHAND.
+ */
+void allow_signal(int sig)
+{
+ spin_lock_irq(&current->sighand->siglock);
+ /* This is only needed for daemonize()'ed kthreads */
+ sigdelset(&current->blocked, sig);
+ /*
+ * Kernel threads handle their own signals. Let the signal code
+ * know it'll be handled, so that they don't get converted to
+ * SIGKILL or just silently dropped.
+ */
+ current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+}
+EXPORT_SYMBOL(allow_signal);
+
+void disallow_signal(int sig)
+{
+ spin_lock_irq(&current->sighand->siglock);
+ current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+}
+EXPORT_SYMBOL(disallow_signal);
+
int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
{
struct task_struct *p = current, *t;
--
1.5.5.1


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