signals: SEND_SIG_NOINFO should be considered as SI_FROMUSER()

No changes in compiled code. The patch adds the new helper, si_fromuser()
and changes check_kill_permission() to use this helper.

The real effect of this patch is that from now we "officially" consider
SEND_SIG_NOINFO signal as "from user-space" signals. This is already true
if we look at the code which uses SEND_SIG_NOINFO, except __send_signal()
has another opinion - see the next patch.

The naming of these special SEND_SIG_XXX siginfo's is really bad
imho.  From __send_signal()'s pov they mean

	SEND_SIG_NOINFO		from user
	SEND_SIG_PRIV		from kernel
	SEND_SIG_FORCED		no info

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Reviewed-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 5 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index f4c145410a8d..57b3516f055b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2102,11 +2102,6 @@ static inline int kill_cad_pid(int sig, int priv)
 #define SEND_SIG_PRIV   ((struct siginfo *) 1)
 #define SEND_SIG_FORCED ((struct siginfo *) 2)
 
-static inline int is_si_special(const struct siginfo *info)
-{
-        return info <= SEND_SIG_FORCED;
-}
-
 /*
  * True if we are on the alternate signal stack.
  */