From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE3314248B1; Mon, 27 Jul 2026 16:36:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785170189; cv=none; b=YPGa7xPhQNZ+CuKoi12DurCnU4k1I48PYtZDzPzAdUKMEtI5BVl22UAY6SqWbxwcD4uKKSqdwQg3Yhc+kwksqcXVgALbHtyTSbJBVd8S+Sy7odWEn6fUoAud3/z3yzYkd5/KJUTkmiBmt4jYerHImgrkWZ3d1q+h1p8m1z8ZaNw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785170189; c=relaxed/simple; bh=tRlFV30ja/8brImGjZrmJZ/1eEggANfYU0WYaHOaBsM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rWU65Mhvw4ogyWBMCJ6T6EKgMkzLg/djYPoFlMiMYtMZnwTS1y1qVM+wb1I3AwCRcEAxS760L6EiOv10ivQvRcdEtD+3/fkifRSbdBhQXDEzaq+BcASxoYkw8Zrvd/McZWdOL4X9wRM06ksyJPx1Ait9o+C1a18Zktnmnvw+ovg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DHC5di3D; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DHC5di3D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFC261F00A3E; Mon, 27 Jul 2026 16:36:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785170188; bh=NwZp8vrcS5zNu4NMBMc7+FtncQiyjKLq2JUaAvCeOIM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=DHC5di3D1bGlMzcG7F1Nm23rfd1M/xEorCZ2zg2aJ4kfE3Ia7aVAOoCnNfdnUCb7u xvwTiIyUUZMVxSba/az3+UtCgzeobMK2K7uUXfMy+Fe5hcQ2pWc7ZdVLkHoR2yG5dr QmlOUpofMIT5FjH1AIflWD/OKts1pPW03Q58+kqfANSl6mi8WsYfNjhTk59EMDBkvD +A7BkHY1tQUPXQOU5XBIHE34ro+EVSnjYsSebzp4lUxOkDyhdHMm3ZUzOIMDbfMHw5 Pox+sEHGUSM1J/dSayDMcF7wZTwhgGGS6E5ymM+SFqBfPru1/PKFg3nrka9Er++OoM dcORIFdnznoYA== Message-ID: <06ead85a-59ef-4c1b-8bb6-8eee5c6a00bd@kernel.org> Date: Mon, 27 Jul 2026 18:36:19 +0200 Precedence: bulk X-Mailing-List: driver-core@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/3] 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" , Baoquan He , Pratyush Yadav , Pasha Tatashin , Jaroslav Kysela , Takashi Iwai , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Simona Vetter , Suren Baghdasaryan , Vlastimil Babka , Dave Young , linux-mm@kvack.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, kexec@lists.infradead.org, driver-core@lists.linux.dev References: <20260725210549.3716546-1-kwilczynski@kernel.org> <20260725210549.3716546-2-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: <20260725210549.3716546-2-kwilczynski@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 7/25/26 23:05, Krzysztof Wilczyński wrote: > Currently, unmap_mapping_pages() and unmap_mapping_range() unmap a > page offset window of an address_space, and code that removes a file, > such as kernfs_drain_open_files(), relies on them to unmap the pages > 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 unmapping the inode's address space cannot reach them, and they stay > live after the file is removed. These VMAs can only be selected by the > struct file they were created through, which is recorded in > vma->vm_file. > > Thus, add unmap_mapping_file(), which walks the VMA interval tree of the > file's f_mapping under i_mmap_lock_read() and unmaps the pages of the > VMAs selected by should_zap_file_vma(), using the same per-VMA zap as > unmap_mapping_pages(). When f_mapping is the file's own inode mapping, > every VMA is zapped, as unmap_mapping_range() does today. When f_mapping > was swapped, only the VMAs with vm_file set to that file are zapped, so > callers do not need to tell the two apart. > > HugeTLB VMAs are skipped with a WARN_ON_ONCE(), as zapping those takes > i_mmap_rwsem for write in hugetlb_zap_begin() and would deadlock against > the read lock held over the walk. > > Signed-off-by: Krzysztof Wilczyński > --- > include/linux/mm.h | 2 ++ > mm/memory.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 50 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..4a09d7b6aa6b 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4423,6 +4423,54 @@ void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, > } > EXPORT_SYMBOL_GPL(unmap_mapping_pages); > > +static inline bool should_zap_file_vma(struct file *file, > + struct vm_area_struct *vma) > +{ > + /* On the file's own inode mapping, zap every VMA */ > + if (file->f_mapping == file_inode(file)->i_mapping) > + return true; > + I assume Sashiko complain applies only when this function would be reuse in other context. But I wonder if that check is even required, shouldn't below check cover this already? I'd expect that "vma->vm_file == file" must always hold. > + /* A swapped mapping also holds VMAs of unrelated files, zap only ours */ > + return vma->vm_file == file; > +} > + > +/** > + * unmap_mapping_file() - Unmap folios from all mmaps of a file. > + * @file: The file to unmap. > + * > + * Unmap the folios of @file from every process that has them mapped. > + * > + * If f_mapping is the file's own inode mapping, they are unmapped > + * from every VMA on that mapping, as unmap_mapping_range() would do. > + * > + * However, if f_mapping was swapped to a different address space at > + * open time, only the VMAs with vm_file set to @file are considered, > + * since that address space also holds mappings of unrelated files. > + * > + * Must not be used on HugeTLB files. HugeTLB VMAs are skipped with > + * a warning. > + */ > +void unmap_mapping_file(struct file *file) > +{ > + struct address_space *mapping = file->f_mapping; > + struct vm_area_struct *vma; > + > + i_mmap_lock_read(mapping); > + if (unlikely(mapping_mapped(mapping))) { > + vma_interval_tree_foreach(vma, &mapping->i_mmap, 0, ULONG_MAX) { Can we just use mapping_rmap_tree_foreach() here, similar to unmap_mapping_range_tree() ? > + cond_resched(); Why that? unmap_mapping_range() doesn't seem to require one so far. -- Cheers, David