linux-kernel - [PATCH 3/3] __set_personality: no need to check the old ->exec

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Date:	Thu, 27 May 2010 17:36:39 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Roland McGrath <roland@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Andi Kleen <andi@...stfloor.org>, "H. Peter Anvin" <hpa@...or.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Richard Henderson <rth@...ddle.net>, wezhang@...hat.com,
	linux-kernel@...r.kernel.org,
	Michael Kerrisk <mtk.manpages@...il.com>,
	William Cohen <wcohen@...hat.com>
Subject: [PATCH 3/3] __set_personality: no need to check the old
	->exec_domain

Cleanup. __set_personality() always changes ->exec_domain/personality,
the special case when ->exec_domain remains the same buys nothing but
complicates the code.

I don't understand why lookup_exec_domain() always succeeds even if
the search in ->exec_domains list fails, we use default_exec_domain
in this case.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---

 kernel/exec_domain.c |   17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

--- 34-rc1/kernel/exec_domain.c~3_CLEANUP_SET_PERSONALITY	2010-05-27 15:54:33.000000000 +0200
+++ 34-rc1/kernel/exec_domain.c	2010-05-27 17:03:29.000000000 +0200
@@ -134,23 +134,14 @@ unregister:
 	return 0;
 }
 
-int
-__set_personality(u_long personality)
+int __set_personality(u_long personality)
 {
-	struct exec_domain	*ep, *oep;
-
-	ep = lookup_exec_domain(personality);
-	if (ep == current_thread_info()->exec_domain) {
-		current->personality = personality;
-		module_put(ep->module);
-		return 0;
-	}
+	struct exec_domain *oep = current_thread_info()->exec_domain;
 
+	current_thread_info()->exec_domain = lookup_exec_domain(personality);
 	current->personality = personality;
-	oep = current_thread_info()->exec_domain;
-	current_thread_info()->exec_domain = ep;
-
 	module_put(oep->module);
+
 	return 0;
 }
 

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