From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 3121B37E918 for ; Thu, 21 Aug 2025 20:08:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755806923; cv=none; b=qbLUOh2Wa0Wt0+gd9F26psTStx5qocXsQaexq03XhGovn/5nskuyAiAB3ufJ6K2DDQZ+VqK9+ttOVgcOAzm3mVrpfMcS9kE/Zs0H6XGd1pmB+zF5zAk0c2BJD6LhjTaCXewuvttDZz2mk00iZnAj1FJyo1sFZ4usf52hoC5N8Go= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755806923; c=relaxed/simple; bh=tCsSQl+WRq69JZRVPLbubBOBHgSgQIUjNop92vdLyr4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gQqI3vlIbOxwqyLuBHN5qq0s0EfPt5X2gKNdFonpAczEogSL6xE1lypHlGBMRc27jDBAZC0Jiu5jV2Gb4I3zaRB0r3aaX0DWDPoTdvMPgwkeZ2TwwYRadmpWE9alf6XxR3Un7CTrOopQDhJ4rMw4TcWCi6G00X0YgQDypnNvrH8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=eKP7XMSr; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eKP7XMSr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755806920; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wK69Pd9CHZjKZhmlaft7kkJNdToX7IH/S9WvVIRScQg=; b=eKP7XMSr7KOy3dO032vYUt593uSWd/F/NgSxCRL7ugc7RzVdNtzgoYDWE2MHUU3NJEpF+o kIc2CH/FvdUqBCduP4M73YGPZzf/qA1Qrzx0BD2ULlPYxpJ68JyOBHU6esM2Bra9vpWqZx tXg38RZ1YIHgczQCx7JdPrFm+l9AUko= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-18-lH4sgdsvMKGkw_WtU0OYmw-1; Thu, 21 Aug 2025 16:08:39 -0400 X-MC-Unique: lH4sgdsvMKGkw_WtU0OYmw-1 X-Mimecast-MFC-AGG-ID: lH4sgdsvMKGkw_WtU0OYmw_1755806918 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-3b9dc5c2820so445759f8f.1 for ; Thu, 21 Aug 2025 13:08:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755806918; x=1756411718; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=wK69Pd9CHZjKZhmlaft7kkJNdToX7IH/S9WvVIRScQg=; b=ZT561D/pbj03dcuMJl7v1Sk/5URsDZYUmcCLHtvKRFYsRBPemHhOvurGrkXzk8dFMg j0dnAXhzARFYXW9XDxehu9azzGAk6nLpQW82JC+fqNrSIRumqRzRod0V67ZmhjQ8Zn3A JKx4RtGboeednhNYdLZjsyXaRuLmuEn+9a7gegW97CKZ2p+Z4FXwKxSYlxJcdnV1r471 t2pJw7xYl6dZQ1WCv+5cLg+E0h/SPdkdiUWnIo6mtm4AEEGJsSaQqb4RoPbjUQRb17SQ vY1FMT2rBtF6ZHgBmLcooMAPJMTyXNPtm4iz0dBtHrtrm2jPoO4vzdZQMgj96yyAVBJ5 S7bA== X-Forwarded-Encrypted: i=1; AJvYcCVa4x+jKazH05Z1cWTqy1oT9kyPwd2tm5WYRHYWWLG9ax3UBZiC/o61J9KKNPJ93mi/R5wFx8obgeKg@vger.kernel.org X-Gm-Message-State: AOJu0YxTFHbUg0iYzFjIdQ/a7U6wjfgEt+eNlXWbGPaV92JgMDFQO2LQ l+5IbmjfQloC2Olad80h2yFWT+5nGqKZTSTV7EkvQHqS0LP7aUE9afiK4L1A1Z67yj/Wiikdzmf 1Go+0FpGF7yHD2ICoETc4IcJnPvBsdJwF67RmSWqLneAafltZYH5eLrILjReZETc= X-Gm-Gg: ASbGncuGncX+1yTbAMecX5q2pgpTcZL7UdqgZT3/3n5PQtIl6IvSovjDxacc8VmeAVF 4SiLdC1gzmK4/xGbKfPRMje1ZrW3yubKzfvG0jQmRij3MRnSoSyXJb+h8o9KZ0C+mTUqZ6FpT+w CMPZjoOIQJvFLUZOvUePr0gvxWKZLoJRgUIuOgWW6JF0fWF7dnajzqx0/Ou88BuGpJqL4JowKCZ 6g8FxC/1+vRZ3H5Auh5c+oFKK1JKQdDE2m0hp6QHS72yhGnPrOtdKQ8m+4th8wti0tW1lg5b8AB cMyLyQ1EIejJiylVJsfstmuZQN/lun/fR2VuzhO16b07Dy5DHVSG3kUCZ8cwSUpqmjhrqvZYO+O m70EhPTSWmNx9UyupDvUgrA== X-Received: by 2002:a5d:64e9:0:b0:3b8:d7c7:62d7 with SMTP id ffacd0b85a97d-3c5daefc298mr218318f8f.16.1755806917859; Thu, 21 Aug 2025 13:08:37 -0700 (PDT) X-Google-Smtp-Source: AGHT+IETBfJ8klmP3LMs+G3FmlUfLKA9Qlb/rzelQ5gyETYamNwKefh2PCq6Da3p1XS4Ia+K1NPGrw== X-Received: by 2002:a5d:64e9:0:b0:3b8:d7c7:62d7 with SMTP id ffacd0b85a97d-3c5daefc298mr218279f8f.16.1755806917364; Thu, 21 Aug 2025 13:08:37 -0700 (PDT) Received: from localhost (p200300d82f26ba0008036ec5991806fd.dip0.t-ipconnect.de. [2003:d8:2f26:ba00:803:6ec5:9918:6fd]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3c4ccbf04fasm3355197f8f.7.2025.08.21.13.08.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Aug 2025 13:08:36 -0700 (PDT) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: David Hildenbrand , Alexander Potapenko , Andrew Morton , Brendan Jackman , Christoph Lameter , Dennis Zhou , Dmitry Vyukov , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux.dev, io-uring@vger.kernel.org, Jason Gunthorpe , Jens Axboe , Johannes Weiner , John Hubbard , kasan-dev@googlegroups.com, kvm@vger.kernel.org, "Liam R. Howlett" , Linus Torvalds , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Lorenzo Stoakes , Marco Elver , Marek Szyprowski , Michal Hocko , Mike Rapoport , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, Zi Yan Subject: [PATCH RFC 32/35] mm/gup: drop nth_page() usage in unpin_user_page_range_dirty_lock() Date: Thu, 21 Aug 2025 22:06:58 +0200 Message-ID: <20250821200701.1329277-33-david@redhat.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250821200701.1329277-1-david@redhat.com> References: <20250821200701.1329277-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit There is the concern that unpin_user_page_range_dirty_lock() might do some weird merging of PFN ranges -- either now or in the future -- such that PFN range is contiguous but the page range might not be. Let's sanity-check for that and drop the nth_page() usage. Signed-off-by: David Hildenbrand --- mm/gup.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index f017ff6d7d61a..0a669a766204b 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -237,7 +237,7 @@ void folio_add_pin(struct folio *folio) static inline struct folio *gup_folio_range_next(struct page *start, unsigned long npages, unsigned long i, unsigned int *ntails) { - struct page *next = nth_page(start, i); + struct page *next = start + i; struct folio *folio = page_folio(next); unsigned int nr = 1; @@ -342,6 +342,9 @@ EXPORT_SYMBOL(unpin_user_pages_dirty_lock); * "gup-pinned page range" refers to a range of pages that has had one of the * pin_user_pages() variants called on that page. * + * The page range must be truly contiguous: the page range corresponds + * to a contiguous PFN range and all pages can be iterated naturally. + * * For the page ranges defined by [page .. page+npages], make that range (or * its head pages, if a compound page) dirty, if @make_dirty is true, and if the * page range was previously listed as clean. @@ -359,6 +362,8 @@ void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages, struct folio *folio; unsigned int nr; + VM_WARN_ON_ONCE(!page_range_contiguous(page, npages)); + for (i = 0; i < npages; i += nr) { folio = gup_folio_range_next(page, npages, i, &nr); if (make_dirty && !folio_test_dirty(folio)) { -- 2.50.1