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signals: mv {dis,}allow_signal() from sched.h/exit.c to signal.[ch]

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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>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2014-06-06 14:36:53 -07:00 committed by Linus Torvalds
parent afe2b0386a
commit 0341729b4b
4 changed files with 31 additions and 42 deletions
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3
include/linux/sched.h
View file

@ -2414,9 +2414,6 @@ 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 *);

2
include/linux/signal.h
View file

@ -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,

39
kernel/exit.c
View file

@ -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_MEMCG
/*
* A task is exiting. If it owned this mm, find a new owner for the mm.

29
kernel/signal.c
View file

@ -3066,6 +3066,35 @@ 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;