From: Oleg Nesterov <oleg@redhat.com>
Date: Wed, 23 Sep 2009 22:56:48 +0000 (-0700)
Subject: do_wait-wakeup-optimization: fix child_wait_callback()->eligible_child() usage
X-Git-Tag: v2.6.32-rc1~108
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5c01ba49e6647d86bc7576105f82027200d1f303;p=pandora-kernel.git

do_wait-wakeup-optimization: fix child_wait_callback()->eligible_child() usage

child_wait_callback()->eligible_child() is not right, we can miss the
wakeup if the task was detached before __wake_up_parent() and the caller
of do_wait() didn't use __WALL.

Move ->wo_pid checks from eligible_child() to the new helper,
eligible_pid(), and change child_wait_callback() to use it instead of
eligible_child().

Note: actually I think it would be better to fix the __WCLONE check in
eligible_child(), it doesn't look exactly right.  But it is not clear what
is the supposed behaviour, and any change is user-visible.

Reported-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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