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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A355DC4451C for ; Tue, 21 Jul 2026 19:20:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3D2C26B007B; Tue, 21 Jul 2026 15:20:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3AB436B008A; Tue, 21 Jul 2026 15:20:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 299A26B008C; Tue, 21 Jul 2026 15:20:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id E708D6B007B for ; Tue, 21 Jul 2026 15:20:10 -0400 (EDT) Received: from smtpin19.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 6AD20A083F for ; Tue, 21 Jul 2026 19:20:10 +0000 (UTC) X-FDA: 85013749380.19.045BD07 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf13.hostedemail.com (Postfix) with ESMTP id A28DA20004 for ; Tue, 21 Jul 2026 19:20:08 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=SYK1MxMD; spf=pass (imf13.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1784661608; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=fbtv0vw1LlTZUCiZD8t3HdgT+DZEZ+c4X5oV0q2qGp0=; b=15YNu4VPZHWKRCDNpZNBHCMH0WPUuPMyQUj7yJphBw3q/OscjMH4JEjACOIxSq4U5x3qJ/ LLIW9U0HUqFDYvdLNZKshD9lHCNBOBQ+ZT1/IDl46MInSt4d7bduBiT7vkFIpnT9spDw25 pex5asIXsilxAYxdSPqy4HQFA/j2fvs= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=SYK1MxMD; spf=pass (imf13.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1784661608; b=cXdiCUaBNnTQOfDYuqUJnuUzM9fEnZFKEGWs292xSTeo5l4/hucAemW9bC8KdG4YdZ4A5l 1c/ty9K2omZqgy1BoIzdI4YkZ5Xa5MAOmSx3y76/+jE9E5dqKLwYHGdYQAOzPoielkz2Ao Q6BJF3fUaQwuyylm/Q/M+RN7+dvOTIc= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 20E7C404E1; Tue, 21 Jul 2026 19:20:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A36DF1F00A3A; Tue, 21 Jul 2026 19:20:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784661607; bh=fbtv0vw1LlTZUCiZD8t3HdgT+DZEZ+c4X5oV0q2qGp0=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=SYK1MxMDQ4Ju4xurEh0nrhuHZHxv4A0QZ1Bge1pFLQOi9VrJbPQfw3EqoddRVH9IO 6qInYd0gsSaFvE9ucIK/mVz1sGl/97DH+imBNDenFeN7hpzhC120OKnvcYr2t1IyWa nIzrT1Ud8MvuGarRrIfFx7677btQhuLafF+A+z7w8x55g4FkmQfrt42NQW/Slyu49P 22gtk6y36rTnkTapLdn/0cWqAdHD5ECZom4JJCrIS+zi/+YqPRDqBrpBegikW7jyIC FT9IrELkmXzXY+JvPJ4YvLcfCJYg1V3xYawMu/U2m+vpNvLzDUeyZPcZ/BL7uX0fBH YRPirVPljhpIA== Message-ID: <5a43053d-8d08-4fda-82e3-bda10ca79c92@kernel.org> Date: Tue, 21 Jul 2026 21:19:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] mm: Add unmap_mapping_file() helper To: =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Andrew Morton , Greg Kroah-Hartman , Tejun Heo , Bjorn Helgaas Cc: Bjorn Helgaas , Manivannan Sadhasivam , Lorenzo Pieralisi , "Liam R . Howlett" , Dan Williams , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Simona Vetter , Suren Baghdasaryan , Vlastimil Babka , linux-pci@vger.kernel.org, linux-mm@kvack.org, driver-core@lists.linux.dev, Christian Brauner References: <20260721185252.1670958-1-kwilczynski@kernel.org> <20260721185252.1670958-2-kwilczynski@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260721185252.1670958-2-kwilczynski@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: A28DA20004 X-Rspamd-Server: rspam01 X-Stat-Signature: pe5uixxf33kwue7a3rca1ax6rssk58i1 X-HE-Tag: 1784661608-988194 X-HE-Meta: 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 wu/Xs6XC DffBo0yKXYcszqur80Wasv42+K31n/xrR8EYM9w4eEeScds3fpRR2tPHoDPnjQ/FHElU+jIewafKmRvhMIFjvN9LNiDfXqtzzcYe0fgmdXu/2m4NjccwpHmKzOXwanqJifqnRkBiDssAiZGeUG+5GruxxFtY64CQ5eqRX5E1MCQy9KsU+IwU57SNhgvh7nER55EZFg1TYDrKEvRv0mrrHQ6ODc0R+WuBC34egDULXbYYgtG/a/yY6KkBY0YhzOP2X/VFNemJRJ8sqzGqL9alx2ZCiRtwLWLPD5OlTVpAYOH4Ww5szwNyZSurteHXHjntQfaoXfAaQWrrjRVRsxxYUCBTknc2cvHc7nUXD Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/21/26 20:52, Krzysztof Wilczyński wrote: > Currently, unmap_mapping_pages() and unmap_mapping_range() unmap > a page offset window of an address_space, and teardown paths such > as kernfs_drain_open_files() rely on them to remove the mappings > of a file that is going away. > > Files with f_mapping swapped to a shared address space at open time, > such as PCI resource files using iomem_get_mapping(), have their > VMAs attached to the shared mapping instead of the file's own inode > mapping, so a teardown that unmaps the inode's address space cannot > reach them, and they stay live after the file is removed. As such, > the only correct discriminator for these VMAs is the originating > struct file recorded in vma->vm_file. > > Add unmap_mapping_file(), which walks the VMA interval tree of the > file's f_mapping under i_mmap_lock_read() and zaps every VMA with > vm_file set to the given file, using the same per-VMA zap teardown > as unmap_mapping_pages(). > > Signed-off-by: Krzysztof Wilczyński > --- > include/linux/mm.h | 2 ++ > mm/memory.c | 26 ++++++++++++++++++++++++++ > 2 files changed, 28 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 485df9c2dbdd..e882a03eaddd 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3183,6 +3183,7 @@ extern int fixup_user_fault(struct mm_struct *mm, > bool *unlocked); > void unmap_mapping_pages(struct address_space *mapping, > pgoff_t start, pgoff_t nr, bool even_cows); > +void unmap_mapping_file(struct file *file); > void unmap_mapping_range(struct address_space *mapping, > loff_t const holebegin, loff_t const holelen, int even_cows); > #else > @@ -3203,6 +3204,7 @@ static inline int fixup_user_fault(struct mm_struct *mm, unsigned long address, > } > static inline void unmap_mapping_pages(struct address_space *mapping, > pgoff_t start, pgoff_t nr, bool even_cows) { } > +static inline void unmap_mapping_file(struct file *file) { } > static inline void unmap_mapping_range(struct address_space *mapping, > loff_t const holebegin, loff_t const holelen, int even_cows) { } > #endif > diff --git a/mm/memory.c b/mm/memory.c > index ff338c2abe92..f9cfb88ac4f7 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4423,6 +4423,32 @@ void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, > } > EXPORT_SYMBOL_GPL(unmap_mapping_pages); > > +/** > + * unmap_mapping_file() - Unmap all mmaps of an open file. > + * @file: The file to unmap. We are unmapping pages/folios, not really mmaps. "Unmap folio from all mmaps of a file." ? > + * > + * Unmap every VMA with vm_file set to @file, regardless of the address Again, we are not unmapping VMAs, we are unmapping pages/folios within all VMAs that map the file. > + * space it is attached to. This also covers files with f_mapping > + * swapped to a different address space at open time, since such VMAs > + * cannot be found through the file's own inode mapping. God this is confusing :) Sorry for the stupid question, but why can't we call unmap_mapping_range(file->f_mapping, 0, 0, 1); What is a bit annoying is that you now do in the caller: if (of->file->f_mapping != inode->i_mapping) unmap_mapping_file(of->file); else unmap_mapping_range(inode->i_mapping, 0, 0, 1); Shouldn't we just have one function that takes care of that internally ... so it's harder to get wrong? -- Cheers, David