From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754060Ab3JBOb2 (ORCPT ); Wed, 2 Oct 2013 10:31:28 -0400 Received: from cantor2.suse.de ([195.135.220.15]:49029 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753339Ab3JBO3A (ORCPT ); Wed, 2 Oct 2013 10:29:00 -0400 From: Jan Kara To: LKML Cc: linux-mm@kvack.org, Jan Kara , Mike Marciniszyn , Roland Dreier , linux-rdma@vger.kernel.org Subject: [PATCH 22/26] ib: Convert ipath_user_sdma_pin_pages() to use get_user_pages_unlocked() Date: Wed, 2 Oct 2013 16:28:03 +0200 Message-Id: <1380724087-13927-23-git-send-email-jack@suse.cz> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1380724087-13927-1-git-send-email-jack@suse.cz> References: <1380724087-13927-1-git-send-email-jack@suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Function 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_unlocked() and leave mmap_sem locking for mm. CC: Mike Marciniszyn CC: Roland Dreier CC: linux-rdma@vger.kernel.org Signed-off-by: Jan Kara --- drivers/infiniband/hw/ipath/ipath_user_sdma.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/hw/ipath/ipath_user_sdma.c b/drivers/infiniband/hw/ipath/ipath_user_sdma.c index f5cb13b21445..462c9b136e85 100644 --- a/drivers/infiniband/hw/ipath/ipath_user_sdma.c +++ b/drivers/infiniband/hw/ipath/ipath_user_sdma.c @@ -280,8 +280,8 @@ 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_unlocked(current, current->mm, addr, + npages, 0, 1, pages); if (ret != npages) { int i; @@ -811,10 +811,7 @@ 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 { -- 1.8.1.4