From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 5 Jan 2017 17:27:34 -0800 From: Andrew Morton To: Ross Zwisler Cc: linux-kernel@vger.kernel.org, Alexander Viro , Arnd Bergmann , Christoph Hellwig , Dan Williams , Dave Chinner , Dave Hansen , Jan Kara , Matthew Wilcox , linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@ml01.01.org Subject: Re: [PATCH v2 0/4] Write protect DAX PMDs in *sync path Message-Id: <20170105172734.23a7603ff19006b49e9ba01a@linux-foundation.org> In-Reply-To: <20170104001349.GA8176@linux.intel.com> References: <1482441536-14550-1-git-send-email-ross.zwisler@linux.intel.com> <20170104001349.GA8176@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: On Tue, 3 Jan 2017 17:13:49 -0700 Ross Zwisler wrote: > On Thu, Dec 22, 2016 at 02:18:52PM -0700, Ross Zwisler wrote: > > Currently dax_mapping_entry_mkclean() fails to clean and write protect the > > pmd_t of a DAX PMD entry during an *sync operation. This can result in > > data loss, as detailed in patch 4. > > > > You can find a working tree here: > > > > https://git.kernel.org/cgit/linux/kernel/git/zwisler/linux.git/log/?h=dax_pmd_clean_v2 > > > > This series applies cleanly to mmotm-2016-12-19-16-31. > > > > Changes since v1: > > - Included Dan's patch to kill DAX support for UML. > > - Instead of wrapping the DAX PMD code in dax_mapping_entry_mkclean() in > > an #ifdef, we now create a stub for pmdp_huge_clear_flush() for the case > > when CONFIG_TRANSPARENT_HUGEPAGE isn't defined. (Dan & Jan) > > > > Dan Williams (1): > > dax: kill uml support > > > > Ross Zwisler (3): > > dax: add stub for pmdp_huge_clear_flush() > > mm: add follow_pte_pmd() > > dax: wrprotect pmd_t in dax_mapping_entry_mkclean > > > > fs/Kconfig | 2 +- > > fs/dax.c | 49 ++++++++++++++++++++++++++++++------------- > > include/asm-generic/pgtable.h | 10 +++++++++ > > include/linux/mm.h | 4 ++-- > > mm/memory.c | 41 ++++++++++++++++++++++++++++-------- > > 5 files changed, 79 insertions(+), 27 deletions(-) > > Well, 0-day found another architecture that doesn't define pmd_pfn() et al., > so we'll need some more fixes. (Thank you, 0-day, for the coverage!) > > I have to apologize, I didn't understand that Dan intended his "dax: kill uml > support" patch to land in v4.11. I thought he intended it as a cleanup to my > series, which really needs to land in v4.10. That's why I folded them > together into this v2, along with the wrapper suggested by Jan. > > Andrew, does it work for you to just keep v1 of this series, and eventually > send that to Linus for v4.10? > > https://lkml.org/lkml/2016/12/20/649 > > You've already pulled that one into -mm, and it does correctly solve the data > loss issue. > > That would let us deal with getting rid of the #ifdef, blacklisting > architectures and introducing the pmdp_huge_clear_flush() strub in a follow-on > series for v4.11. I have mm-add-follow_pte_pmd.patch and dax-wrprotect-pmd_t-in-dax_mapping_entry_mkclean.patch queued for 4.10. Please (re)send any additional patches, indicating for each one whether you believe it should also go into 4.10? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org