From patchwork Fri Nov 29 14:03:08 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 295385 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id EF5982C00CA for ; Sat, 30 Nov 2013 01:05:12 +1100 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1VmOgt-0004QH-4d; Fri, 29 Nov 2013 14:05:07 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1VmOf0-0002gQ-OL for kernel-team@lists.ubuntu.com; Fri, 29 Nov 2013 14:03:10 +0000 Received: from bl15-102-62.dsl.telepac.pt ([188.80.102.62] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1VmOf0-0005JI-0x; Fri, 29 Nov 2013 14:03:10 +0000 From: Luis Henriques To: Jan Kara Subject: [3.5.y.z extended stable] Patch "IB/ipath: Convert ipath_user_sdma_pin_pages() to use" has been added to staging queue Date: Fri, 29 Nov 2013 14:03:08 +0000 Message-Id: <1385733788-1360-1-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 X-Extended-Stable: 3.5 Cc: Roland Dreier , Mike Marciniszyn , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled IB/ipath: Convert ipath_user_sdma_pin_pages() to use to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From b8bb3664df3dcf6f53f64e098707b7923d6f60aa Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 4 Oct 2013 09:29:06 -0400 Subject: IB/ipath: Convert ipath_user_sdma_pin_pages() to use get_user_pages_fast() commit 4adcf7fb6783e354aab38824d803fa8c4f8e8a27 upstream. ipath_user_sdma_queue_pkts() gets called with mmap_sem held for writing. Except for get_user_pages() deep down in ipath_user_sdma_pin_pages() we don't seem to need mmap_sem at all. Even more interestingly the function ipath_user_sdma_queue_pkts() (and also ipath_user_sdma_coalesce() called somewhat later) call copy_from_user() which can hit a page fault and we deadlock on trying to get mmap_sem when handling that fault. So just make ipath_user_sdma_pin_pages() use get_user_pages_fast() and leave mmap_sem locking for mm. This deadlock has actually been observed in the wild when the node is under memory pressure. Signed-off-by: Jan Kara Signed-off-by: Mike Marciniszyn [ Merged in fix for call to get_user_pages_fast from Tetsuo Handa . - Roland ] Signed-off-by: Roland Dreier Signed-off-by: Luis Henriques --- drivers/infiniband/hw/ipath/ipath_user_sdma.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) -- 1.8.3.2 diff --git a/drivers/infiniband/hw/ipath/ipath_user_sdma.c b/drivers/infiniband/hw/ipath/ipath_user_sdma.c index f5cb13b..cc04b7b 100644 --- a/drivers/infiniband/hw/ipath/ipath_user_sdma.c +++ b/drivers/infiniband/hw/ipath/ipath_user_sdma.c @@ -280,9 +280,7 @@ static int ipath_user_sdma_pin_pages(const struct ipath_devdata *dd, int j; int ret; - ret = get_user_pages(current, current->mm, addr, - npages, 0, 1, pages, NULL); - + ret = get_user_pages_fast(addr, npages, 0, pages); if (ret != npages) { int i; @@ -811,10 +809,7 @@ int ipath_user_sdma_writev(struct ipath_devdata *dd, while (dim) { const int mxp = 8; - down_write(¤t->mm->mmap_sem); ret = ipath_user_sdma_queue_pkts(dd, pq, &list, iov, dim, mxp); - up_write(¤t->mm->mmap_sem); - if (ret <= 0) goto done_unlock; else {