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 84A354F93B3 for ; Fri, 18 Sep 2026 13:47:25 +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=1789739246; cv=none; b=pUtKHgSNM+p4/K8LgKqwgcBB4x3MCf5ZAAuu3H0J7Ry2g8Ouzp/dRq/nIH/Yvt+Ow3XggX9eIFK/xjhiB7+4f46Hz3fzfrHx2xMkNILpGHoWee53had3cIFkUAs+n1jdrWy+FBdAs9/8Kt8Aqa++Vp3/JhjvJcyyMmddh9bzvJk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789739246; c=relaxed/simple; bh=NP4whSnqaZ2VBngE/e8wB2yHxsTbGNa+qsx2e5Ijrbg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OftwhqjB/gWVUisWlhAQowpvatoAN1WIO98ss1MSG6o+ZyqbeujX0ActQ4P+7FfX3xpyFx30xKXBMu11EtoBni/p5UYrGzlVEF13GMTC8CzEt+5/1MaPeyC1nlnJEEx73Mhy66JAIYvoaqkSuGKXwfOMoCQX4GVNx4vwCRRyp40= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=F9ZUhBUH; 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="F9ZUhBUH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F29A1F00898; Fri, 18 Sep 2026 13:47:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789739245; bh=zDB8ZNrlloa4K4BhhwSa+v9ApPYQhDBrcYUmm+5KlB4=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=F9ZUhBUHGtWbiYQJVewlMYWp6udci2KIiFZLV4F7Cxb0UcEtK9ErRh/K0jtkgbpzi 8czAX5BPGeqlacdyzDKafNHDHbtZdPv/ngZU5UcI/ERMTB6iwzpB+mnt7/iD+PIK52 Aw0IVWIxLOeb6jZwmtaCrvYB9AGdTS1qEFBeekYfe8GxFz7IvfsHeJD6nVvO6hfsgK MHj2AspFZHalCqpmD0C2+zmzFZEOyMbCRyR6x6awZa1lZNc+YvYIM3isj9p1OyGjzd YqhPXY5IEKN/uyEGBcjf1b7m6sLMKamDtFfnF/AfWv1ncitJ5NNZbvfK4UBXQKGaJi Nq3A15d1BYm5w== Message-ID: <813a2644-fa9f-4ee7-8655-ca69ef0e8a98@kernel.org> Date: Fri, 18 Sep 2026 15:47:18 +0200 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 11/15] filemap: Add hwpoison handling to filemap_read() To: Matthew Wilcox , Pedro Falcato Cc: Andrew Morton , Jane Chu , linux-mm@kvack.org, Muchun Song , Oscar Salvador , Miaohe Lin , Naoya Horiguchi , Jan Kara , linux-fsdevel@vger.kernel.org, Christian Brauner , Jiaqi Yan References: <20260805210557.1118966-1-willy@infradead.org> <20260805210557.1118966-12-willy@infradead.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/13/26 18:33, Matthew Wilcox wrote: > On Thu, Aug 13, 2026 at 11:55:44AM +0100, Pedro Falcato wrote: >>> +static size_t adjust_range_hwpoison(const struct folio *folio, size_t offset, >>> + size_t bytes) >>> +{ >>> + const struct page *page = folio_page(folio, offset / PAGE_SIZE); >>> + size_t safe_bytes; >> offset >> PAGE_SHIFT would probably be more idiomatic > > $ git grep '/ PAGE_SIZE' mm fs |wc -l > 116 > $ git grep '>> PAGE_SHIFT' mm fs |wc -l > 656 > > it seems relatively common. Personally I find / easier to understand > because I sometimes get confused between left and right shifts. I > don't think I've ever been confused between multiply and divide ;-) Linus once explained why ">> PAGE_SHIFT" is preferable when the type of the function might be signed, as the shift generates better code. I personally find "offset / PAGE_SIZE" more intuitive, but I also have sympathy for PHYS_PFN() to abstract the operation. (SIZE_TO_PAGES would be a bit mouthful so I wouldn't ever dare suggesting to introduce a new helper) -- Cheers, David