From: Oleg Nesterov Date: Wed, 26 May 2010 21:43:10 +0000 (-0700) Subject: exit: exit_notify() can trust signal->notify_count < 0 X-Git-Tag: v2.6.35-rc1~171 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9c3391684415c9dca239130d9e433a60a4edf04b;p=pandora-kernel.git exit: exit_notify() can trust signal->notify_count < 0 signal_struct->count in its current form must die. - it has no reasons to be atomic_t - it looks like a reference counter, but it is not - otoh, we really need to make task->signal refcountable, just look at the extremely ugly task_rq_unlock_wait() called from __exit_signals(). - we should change the lifetime rules for task->signal, it should be pinned to task_struct. We have a lot of code which can be simplified after that. - it is not needed! while the code is correct, any usage of this counter is artificial, except fs/proc uses it correctly to show the number of threads. This series removes the usage of sig->count from exit pathes. This patch: Now that Veaceslav changed copy_signal() to use zalloc(), exit_notify() can just check notify_count < 0 to ensure the execing sub-threads needs the notification from us. No need to do other checks, notify_count != 0 must always mean ->group_exit_task != NULL is waiting for us. Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath Cc: Veaceslav Falico Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed