From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56453) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X2NlC-0003x1-Be for qemu-devel@nongnu.org; Wed, 02 Jul 2014 12:52:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X2Nl6-00084o-7U for qemu-devel@nongnu.org; Wed, 02 Jul 2014 12:51:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:64591) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X2Nl5-00084W-Uo for qemu-devel@nongnu.org; Wed, 02 Jul 2014 12:51:48 -0400 From: Andrea Arcangeli Date: Wed, 2 Jul 2014 18:50:09 +0200 Message-Id: <1404319816-30229-4-git-send-email-aarcange@redhat.com> In-Reply-To: <1404319816-30229-1-git-send-email-aarcange@redhat.com> References: <1404319816-30229-1-git-send-email-aarcange@redhat.com> Subject: [Qemu-devel] [PATCH 03/10] mm: PT lock: export double_pt_lock/unlock List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Robert Love , Dave Hansen , Jan Kara , Neil Brown , Stefan Hajnoczi , Andrew Jones , KOSAKI Motohiro , Michel Lespinasse , Andrea Arcangeli , Taras Glek , Juan Quintela , Hugh Dickins , Isaku Yamahata , Mel Gorman , Android Kernel Team , Mel Gorman , "\\\"Dr. David Alan Gilbert\\\"" , "Huangpeng (Peter)" , Anthony Liguori , Mike Hommey , Keith Packard , Wenchao Xia , Minchan Kim , Dmitry Adamushko , Johannes Weiner , Paolo Bonzini , Andrew Morton Those two helpers are needed by remap_anon_pages. Signed-off-by: Andrea Arcangeli --- include/linux/mm.h | 4 ++++ mm/fremap.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 33 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 00faeda..0a7f0e1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1401,6 +1401,10 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a } #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */ +/* mm/fremap.c */ +extern void double_pt_lock(spinlock_t *ptl1, spinlock_t *ptl2); +extern void double_pt_unlock(spinlock_t *ptl1, spinlock_t *ptl2); + #if USE_SPLIT_PTE_PTLOCKS #if ALLOC_SPLIT_PTLOCKS void __init ptlock_cache_init(void); diff --git a/mm/fremap.c b/mm/fremap.c index 72b8fa3..1e509f7 100644 --- a/mm/fremap.c +++ b/mm/fremap.c @@ -281,3 +281,32 @@ out_freed: return err; } + +void double_pt_lock(spinlock_t *ptl1, + spinlock_t *ptl2) + __acquires(ptl1) + __acquires(ptl2) +{ + spinlock_t *ptl_tmp; + + if (ptl1 > ptl2) { + /* exchange ptl1 and ptl2 */ + ptl_tmp = ptl1; + ptl1 = ptl2; + ptl2 = ptl_tmp; + } + /* lock in virtual address order to avoid lock inversion */ + spin_lock(ptl1); + if (ptl1 != ptl2) + spin_lock_nested(ptl2, SINGLE_DEPTH_NESTING); +} + +void double_pt_unlock(spinlock_t *ptl1, + spinlock_t *ptl2) + __releases(ptl1) + __releases(ptl2) +{ + spin_unlock(ptl1); + if (ptl1 != ptl2) + spin_unlock(ptl2); +}