From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48275) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xa6YZ-0003Ik-3Y for qemu-devel@nongnu.org; Fri, 03 Oct 2014 13:22:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xa6YR-0001pC-2Q for qemu-devel@nongnu.org; Fri, 03 Oct 2014 13:22:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15029) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xa6YQ-0001p5-QW for qemu-devel@nongnu.org; Fri, 03 Oct 2014 13:22:07 -0400 From: Andrea Arcangeli Date: Fri, 3 Oct 2014 19:07:59 +0200 Message-Id: <1412356087-16115-10-git-send-email-aarcange@redhat.com> In-Reply-To: <1412356087-16115-1-git-send-email-aarcange@redhat.com> References: <1412356087-16115-1-git-send-email-aarcange@redhat.com> Subject: [Qemu-devel] [PATCH 09/17] 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-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org Cc: Robert Love , Dave Hansen , Jan Kara , Neil Brown , Stefan Hajnoczi , Andrew Jones , KOSAKI Motohiro , Michel Lespinasse , Taras Glek , Juan Quintela , Hugh Dickins , Isaku Yamahata , Mel Gorman , Sasha Levin , Android Kernel Team , "\\\"Dr. David Alan Gilbert\\\"" , "Huangpeng (Peter)" , Andres Lagar-Cavilla , Christopher Covington , Anthony Liguori , Paolo Bonzini , Keith Packard , Wenchao Xia , Andy Lutomirski , Minchan Kim , Dmitry Adamushko , Johannes Weiner , Mike Hommey , Andrew Morton , Linus Torvalds , Peter Feiner 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 bf3df07..71dbe03 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1408,6 +1408,10 @@ 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); +}