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Commit bb7efee2 authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

signal: cleanup sys_rt_sigprocmask() 



sys_rt_sigprocmask() looks unnecessarily complicated, simplify it.
We can just read current->blocked lockless unconditionally before
anything else and then copy-to-user it if needed.  At worst we
copy 4 words on mips.

We could copy-to-user the old mask first and simplify the code even
more, but the patch tries to keep the current behaviour: we change
current->block even if copy_to_user(oset) fails.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Reviewed-by: default avatarMatt Fleming <matt.fleming@linux.intel.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
parent e9bd3f0f

kernel/signal.c

+16 −22
Original line number Diff line number Diff line
@@ -2364,40 +2364,34 @@ int sigprocmask(int how, sigset_t *set, sigset_t *oldset) 
 *  @oset: previous value of signal mask if non-null

 *  @sigsetsize: size of sigset_t type

 */

SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,

SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,

		sigset_t __user *, oset, size_t, sigsetsize)

{

	int error = -EINVAL;

	sigset_t old_set, new_set;

	int error;



	/* XXX: Don't preclude handling different sized sigset_t's.  */

	if (sigsetsize != sizeof(sigset_t))

		goto out;

		return -EINVAL;



	if (set) {

		error = -EFAULT;

		if (copy_from_user(&new_set, set, sizeof(*set)))

			goto out;

	old_set = current->blocked;



	if (nset) {

		if (copy_from_user(&new_set, nset, sizeof(sigset_t)))

			return -EFAULT;

		sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));



		error = sigprocmask(how, &new_set, &old_set);

		error = sigprocmask(how, &new_set, NULL);

		if (error)

			goto out;

		if (oset)

			goto set_old;

	} else if (oset) {

		spin_lock_irq(&current->sighand->siglock);

		old_set = current->blocked;

		spin_unlock_irq(&current->sighand->siglock);

			return error;

	}



	set_old:

		error = -EFAULT;

		if (copy_to_user(oset, &old_set, sizeof(*oset)))

			goto out;

	if (oset) {

		if (copy_to_user(oset, &old_set, sizeof(sigset_t)))

			return -EFAULT;

	}

	error = 0;

out:

	return error;



	return 0;

}



long do_sigpending(void __user *set, unsigned long sigsetsize)