Message-ID: <c3cc49b6-1ad3-f5aa-50bb-a12f3bbb377a@collabora.com>
Date:   Mon, 30 Jan 2023 14:10:11 +0500
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Cc:     Muhammad Usama Anjum <usama.anjum@collabora.com>,
        David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
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        <emmir@google.com>, Andrei Vagin <avagin@gmail.com>,
        Danylo Mocherniuk <mdanylo@google.com>,
        Paul Gofman <pgofman@codeweavers.com>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Shuah Khan <shuah@kernel.org>,
        Christian Brauner <brauner@kernel.org>,
        Yang Shi <shy828301@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Liam R . Howlett" <Liam.Howlett@oracle.com>,
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        Alex Sierra <alex.sierra@amd.com>,
        Matthew Wilcox <willy@infradead.org>,
        Pasha Tatashin <pasha.tatashin@soleen.com>,
        Mike Rapoport <rppt@kernel.org>, Nadav Amit <namit@vmware.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        "Gustavo A . R . Silva" <gustavoars@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
        Greg KH <gregkh@linuxfoundation.org>, kernel@collabora.com
Subject: Re: [PATCH v8 2/4] userfaultfd: split mwriteprotect_range()
Content-Language: en-US
To:     Peter Xu <peterx@redhat.com>
References: <20230124084323.1363825-1-usama.anjum@collabora.com>
 <20230124084323.1363825-3-usama.anjum@collabora.com> <Y9QEdbkZxOJ10oEJ@x1n>
From:   Muhammad Usama Anjum <usama.anjum@collabora.com>
In-Reply-To: <Y9QEdbkZxOJ10oEJ@x1n>
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On 1/27/23 10:05 PM, Peter Xu wrote:
> On Tue, Jan 24, 2023 at 01:43:21PM +0500, Muhammad Usama Anjum wrote:
>> Split mwriteprotect_range() to create a unlocked version. This
>> will be used in the next patch to write protect a memory area.
>> Add a helper function, wp_range_async() as well.
>>
>> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
> 
> IIUC this patch is not needed.  You have a stable vma, so I think you can
> directly use uffd_wp_range(), while most of the mwriteprotect_range() is
> not needed.
> 
> There's one trivial detail of ignoring userfaultfd_ctx->mmap_changing when
> it's set to true, but I don't think it applies here either because it was
> used to resolve a problem in uffd non-cooperative mode on the predictable
> behavior of events, here I don't think it matters a lot either.
> 
Thanks, I'll drop this patch and do direct wiring to uffd_wp_range().

-- 
BR,
Muhammad Usama Anjum