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From: Kirill Tkhai <ktkhai@odin.com>
To: <linux-kernel@vger.kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	Michal Hocko <mhocko@suse.cz>, "Rik van Riel" <riel@redhat.com>,
	Ionut Alexa <ionut.m.alexa@gmail.com>,
	Peter Hurley <peter@hurleysoftware.com>,
	Kirill Tkhai <tkhai@yandex.ru>
Subject: [PATCH RFC 04/13] exit: Small refactoring mm_update_next_owner()
Date: Mon, 25 May 2015 20:44:41 +0300	[thread overview]
Message-ID: <1432575881.6866.36.camel@odin.com> (raw)
In-Reply-To: <20150525162722.5171.15901.stgit@pro>

This will be used in next patches. No functionality change.

Signed-off-by: Kirill Tkhai <ktkhai@odin.com>
---
 kernel/exit.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index a1b2bf7..5e82787 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -322,16 +322,20 @@ void mm_update_next_owner(struct mm_struct *mm)
 	 * Search in the children
 	 */
 	list_for_each_entry(c, &p->children, sibling) {
-		if (c->mm == mm)
+		if (c->mm == mm) {
+			get_task_struct(c);
 			goto assign_new_owner;
+		}
 	}
 
 	/*
 	 * Search in the siblings
 	 */
 	list_for_each_entry(c, &p->real_parent->children, sibling) {
-		if (c->mm == mm)
+		if (c->mm == mm) {
+			get_task_struct(c);
 			goto assign_new_owner;
+		}
 	}
 
 	/*
@@ -341,8 +345,10 @@ void mm_update_next_owner(struct mm_struct *mm)
 		if (g->flags & PF_KTHREAD)
 			continue;
 		for_each_thread(g, c) {
-			if (c->mm == mm)
+			if (c->mm == mm) {
+				get_task_struct(c);
 				goto assign_new_owner;
+			}
 			if (c->mm)
 				break;
 		}
@@ -358,7 +364,6 @@ void mm_update_next_owner(struct mm_struct *mm)
 
 assign_new_owner:
 	BUG_ON(c == p);
-	get_task_struct(c);
 	/*
 	 * The task_lock protects c->mm from changing.
 	 * We always want mm->owner->mm == mm




  parent reply	other threads:[~2015-05-25 17:44 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20150525162722.5171.15901.stgit@pro>
2015-05-25 17:44 ` [PATCH RFC 01/13] exit: Clarify choice of new parent in forget_original_parent() Kirill Tkhai
2015-05-25 17:44 ` [PATCH RFC 02/13] rwlock_t: Implement double_write_{,un}lock() Kirill Tkhai
2015-05-25 17:44 ` [PATCH RFC 03/13] pid_ns: Implement rwlock_t pid_ns::cr_lock for locking child_reaper Kirill Tkhai
2015-05-25 17:44 ` Kirill Tkhai [this message]
2015-05-25 17:45 ` [PATCH RFC 05/13] fs: Refactoring in get_children_pid() Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 06/13] core: Add rwlock_t task_list::kin_lock Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 07/13] kin_lock: Implement helpers for kin_lock locking Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 08/13] core: Use kin_lock synchronizations between parent and child and for thread group Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 09/13] exit: Use for_each_thread() in do_wait() Kirill Tkhai
2015-05-26 19:46   ` Oleg Nesterov
2015-05-27  9:33     ` Kirill Tkhai
2015-05-27  9:42       ` Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 10/13] exit: Add struct wait_opts's member held_lock and use it for tasklist_lock Kirill Tkhai
2015-05-25 17:46 ` [PATCH RFC 11/13] exit: Syncronize on kin_lock while do_notify_parent() Kirill Tkhai
2015-05-25 17:46 ` [PATCH RFC 12/13] exit: Delete write dependence on tasklist_lock in exit_notify() Kirill Tkhai
2015-05-25 17:46 ` [PATCH RFC 13/13] core: Nest tasklist_lock into task_struct::kin_lock Kirill Tkhai

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