Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v6 06/13] mm, dev_pagemap: Do not clear ->mapping on final
 put
To:     =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>
Cc:     Dan Williams <dan.j.williams@intel.com>, linux-nvdimm@lists.01.org,
        Jan Kara <jack@suse.cz>, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, linux-mm@kvack.org,
        =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>,
        linux-fsdevel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>, hch@lst.de
References: <153154376846.34503.15480221419473501643.stgit@dwillia2-desk3.amr.corp.intel.com>
 <153154380137.34503.3754023882460956800.stgit@dwillia2-desk3.amr.corp.intel.com>
From:   Dave Jiang <dave.jiang@intel.com>
Openpgp: preference=signencrypt
Autocrypt: addr=dave.jiang@intel.com; prefer-encrypt=mutual; keydata=
 xsPuBE6TbysRDACKOBHZT4ez/3/idMBVQP+cMIJAWfTTLqbHVYLdHMHh4h6IXWLqWgc9AYTx
 /ajdOrBVGSK9kMuvqRi0iRO1QLOMUAIc2n/44vh/3Fe54QYfgbndeXhHZi7YEwjiTCbpQ336
 pS0rS2qQaA8GzFwu96OslLI05j9Ygaqy73qmuk3wxomIYiu9a97aN3oVv1RyTp6gJK1NWT3J
 On17P1yWUYPvY3KJtpVqnRLkLZeOIiOahgf9+qiYqPhKQI1Ycx4YhbqkNmDG1VqdMtEWREZO
 DpTti6oecydN37MW1Y+YSzWYDVLWfoLUr2tBveGCRLf/U2n+Tm2PlJR0IZq+BhtuIUVcRLQW
 vI+XenR8j3vHVNHs9UXW/FPB8Xb5fwY2bJniZ+B4G67nwelhMNWe7H9IcEaI7Eo32fZk+9fo
 x6GDAhdT0pEetwuhkmI0YYD7cQj1mEx1oEbzX2p/HRW9sHTSv0V2zKbkPvii3qgvCoDb1uLd
 4661UoSG0CYaAx8TwBxUqjsBAO9FXDhLHZJadyHmWp64xQGnNgBathuqoSsIWgQWBpfhDACA
 OYftX52Wp4qc3ZT06NPzGTV35xr4DVftxxUHiwzB/bzARfK8tdoW4A44gN3P03DAu+UqLoqm
 UP/e8gSLEjoaebjMu8c2iuOhk1ayHkDPc2gugTgLLBWPkhvIEV4rUV9C7TsgAAvNNDAe8X00
 Tu1m01A4ToLpYsNWEtM9ZRdKXSo6YS45DFRhel29ZRz24j4ZNIxN9Bee/fn7FrL4HgO01yH+
 QULDAtU87AkVoBdU5xBJVj7tGosuV+ia4UCWXjTzb+ERek2503OvNq4xqche3RMoZLsSHiOj
 5PjMNX4EA6pf5kRWdNutjmAsXrpZrnviWMPy+zHUzHIw/gaI00lHMjS0P99A7ay/9BjtsIBx
 lJZ09Kp6SE0EiZpFIxB5D0ji6rHu3Qblwq+WjM2+1pydVxqt2vt7+IZgEB4Qm6rml835UB89
 TTkMtiIXJ+hMC/hajIuFSah+CDkfagcrt1qiaVoEAs/1cCuAER+h5ClMnLZPPxNxphsqkXxn
 3MVJcMEL/iaMimP3oDXJoK3O+u3gC3p55A/LYZJ7hP9lHTT4MtgwmgBp9xPeVFWx3rwQOKix
 SPONHlkjfvn4dUHmaOmJyKgtt5htpox+XhBkuCZ5UWpQ40/GyVypWyBXtqNx/0IKByXy4QVm
 QjUL/U2DchYhW+2w8rghIhkuHX2YOdldyEvXkzN8ysGR31TDwshg600k4Q/UF/MouC2ZNeMa
 y8I0whHBFTwSjN5T1F9cvko4PsHNB3QH4M4tbArwn4RzSX6Hfxoq59ziyI4Et6sE5SyiVEZQ
 DhKZ8VU61uUaYHDdid8xKU4sV5IFCERIoIwieEAkITNvCdFtuXl9gugzld7IHbOTRaGy4M+M
 gOyAvSe5ysBrXhY+B0d+EYif1I8s4PbnkH2xehof++lQuy3+1TZcweSx1f/uF6d92ZDkvJzQ
 QbkicMLaPy0IS5XIMkkpD1zIO0jeaHcTm3uzB9k8N9y4tA2ELWVR/iFZigrtrwpIJtJLUieB
 89EOJLR6xbksSrFhQ80oRGF2ZSBKaWFuZyAoV29yaykgPGRhdmUuamlhbmdAaW50ZWwuY29t
 PsJ9BBMRCAAlAhsjBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUCUZEwDwIZAQAKCRBkFcTx
 ZqO5Ps8HAP4kF/KAor80fNwT7osSHGG5rLFPR/Yc5V0QpqkU8DhZDgEAoStRa/a6Mtq3Ri1H
 B84kFIqSQ9ME5049k6k1K7wdXcvOwE0ETpNvKxAEANGHLx0q/R99wzbVdnRthIZttNQ6M4R8
 AAtEypE9JG3PLrEd9MUB5wf0fB/2Jypec3x935mRW3Zt1i+TrzjQDzMV5RyTtpWI7PwIh5IZ
 0h4OV2yQHFVViHi6lubCRypQYiMzTmEKua3LeBGvUR9vVmpPJZ/UP6VajKqywjPHYBwLAAMF
 A/9B/PdGc1sZHno0ezuwZO2J9BOsvASNUzamO9to5P9VHTA6UqRvyfXJpNxLF1HjT4ax7Xn4
 wGr6V1DCG3JYBmwIZjfinrLINKEK43L+sLbVVi8Mypc32HhNx/cPewROY2vPb4U7y3jhPBtt
 lt0ZMb75Lh7zY3TnGLOx1AEzmqwZSMJhBBgRCAAJBQJOk28rAhsMAAoJEGQVxPFmo7k+qiUB
 AKH0QWC+BBBn3pa9tzOz5hTrup+GIzf5TcuCsiAjISEqAPkBTGk5iiGrrHkxsz8VulDVpNxk
 o6nmKbYpUAltQObU2w==
Message-ID: <3fcb3c8a-2a41-7c78-edde-066c10110d34@intel.com>
Date:   Mon, 23 Jul 2018 09:12:06 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.8.0
MIME-Version: 1.0
In-Reply-To: <153154380137.34503.3754023882460956800.stgit@dwillia2-desk3.amr.corp.intel.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Jerome,
Is it possible to get an ack for this? Thanks!

On 07/13/2018 09:50 PM, Dan Williams wrote:
> MEMORY_DEVICE_FS_DAX relies on typical page semantics whereby ->mapping
> is only ever cleared by truncation, not final put.
> 
> Without this fix dax pages may forget their mapping association at the
> end of every page pin event.
> 
> Move this atypical behavior that HMM wants into the HMM ->page_free()
> callback.
> 
> Cc: <stable@vger.kernel.org>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Jérôme Glisse <jglisse@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> Fixes: d2c997c0f145 ("fs, dax: use page->mapping...")
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  kernel/memremap.c |    1 -
>  mm/hmm.c          |    2 ++
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/memremap.c b/kernel/memremap.c
> index 5857267a4af5..62603634a1d2 100644
> --- a/kernel/memremap.c
> +++ b/kernel/memremap.c
> @@ -339,7 +339,6 @@ void __put_devmap_managed_page(struct page *page)
>  		__ClearPageActive(page);
>  		__ClearPageWaiters(page);
>  
> -		page->mapping = NULL;
>  		mem_cgroup_uncharge(page);
>  
>  		page->pgmap->page_free(page, page->pgmap->data);
> diff --git a/mm/hmm.c b/mm/hmm.c
> index de7b6bf77201..f9d1d89dec4d 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -963,6 +963,8 @@ static void hmm_devmem_free(struct page *page, void *data)
>  {
>  	struct hmm_devmem *devmem = data;
>  
> +	page->mapping = NULL;
> +
>  	devmem->ops->free(devmem, page);
>  }
>  
> 
> _______________________________________________
> Linux-nvdimm mailing list
> Linux-nvdimm@lists.01.org
> https://lists.01.org/mailman/listinfo/linux-nvdimm
>