From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D321C432BE for ; Tue, 31 Aug 2021 20:35:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 095C660ED4 for ; Tue, 31 Aug 2021 20:35:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232803AbhHaUgi (ORCPT ); Tue, 31 Aug 2021 16:36:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:53310 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230236AbhHaUgi (ORCPT ); Tue, 31 Aug 2021 16:36:38 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A6F606103A; Tue, 31 Aug 2021 20:35:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1630442142; bh=s85S8KQXJOb7b1xa7D+f7KxhW9Tjq4i09HM2JGNUPg8=; h=Date:From:To:Subject:From; b=Co8RIRTdtMUHvmbSciQ2jKc61oCL71nvG8zE6WkSY/bS6DP9nxw4uFw5fy9oyWfGT beLndQ5KJXWwIu6E/dvBorN9oc5QZX2IpB8t65aoC3j/LE5O7qA7tezASjnGrKdsnO k4vQ4ZggcrUfAM+/sFcAC9Zse9m+DdjNzZ0Sq3HM= Date: Tue, 31 Aug 2021 13:35:42 -0700 From: akpm@linux-foundation.org To: hch@lst.de, jgg@nvidia.com, lizhijian@cn.fujitsu.com, mm-commits@vger.kernel.org, stable@vger.kernel.org Subject: + mm-hmm-bypass-devmap-pte-when-all-pfn-requested-flags-are-fulfilled.patch added to -mm tree Message-ID: <20210831203542.aBJpj84ci%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled has been added to the -mm tree. Its filename is mm-hmm-bypass-devmap-pte-when-all-pfn-requested-flags-are-fulfilled.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-hmm-bypass-devmap-pte-when-all-pfn-requested-flags-are-fulfilled.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-hmm-bypass-devmap-pte-when-all-pfn-requested-flags-are-fulfilled.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Li Zhijian Subject: mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled Previously, we noticed the one rpma example was failed[1] since 36f30e486d, where it will use ODP feature to do RDMA WRITE between fsdax files. After digging into the code, we found hmm_vma_handle_pte() will still return EFAULT even though all the its requesting flags has been fulfilled. That's because a DAX page will be marked as (_PAGE_SPECIAL | PAGE_DEVMAP) by pte_mkdevmap(). [1]: https://github.com/pmem/rpma/issues/1142 Link: https://lkml.kernel.org/r/20210830094232.203029-1-lizhijian@cn.fujitsu.com Fixes: 405506274922 ("mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling") Signed-off-by: Li Zhijian Reviewed-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Cc: Signed-off-by: Andrew Morton --- mm/hmm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/mm/hmm.c~mm-hmm-bypass-devmap-pte-when-all-pfn-requested-flags-are-fulfilled +++ a/mm/hmm.c @@ -295,10 +295,13 @@ static int hmm_vma_handle_pte(struct mm_ goto fault; /* + * Bypass devmap pte such as DAX page when all pfn requested + * flags(pfn_req_flags) are fulfilled. * Since each architecture defines a struct page for the zero page, just * fall through and treat it like a normal page. */ - if (pte_special(pte) && !is_zero_pfn(pte_pfn(pte))) { + if (pte_special(pte) && !pte_devmap(pte) && + !is_zero_pfn(pte_pfn(pte))) { if (hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0)) { pte_unmap(ptep); return -EFAULT; _ Patches currently in -mm which might be from lizhijian@cn.fujitsu.com are mm-hmm-bypass-devmap-pte-when-all-pfn-requested-flags-are-fulfilled.patch