From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 2E4254A21 for ; Tue, 25 Nov 2025 11:31:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764070308; cv=none; b=qUyi5603xwQSSKbmG5JCdO8FWtU6x/JQBfJp5+wSQaY0pFOpmUbKpPFV8ggOaIzAOy+YxJwWh/VpGul5bq5/zLjs5Sj0QqCQ5fSBRjaGM8Qd7aOQrsUrU3/RgJOvx2wrmIQYRpuIPo+QRu046CfJsEiBvDJVfaMycdCP+408Vow= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764070308; c=relaxed/simple; bh=YLCa0KGEOXMfFb8UjNiMVXlPlvjXuBIpYEPA70WntSE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tqHD/naxQeZ3GIFZI6iB7ssO6/sFu9HJx7SeSIMzLtt39dLdu0Y9ivhOYh49ZGjBpCknLylhFpfIpAdVL6aCDeM1Q8fRBXpHBJPH6tSuISQ964DjmuHv+VUM+6iNWJv3QyHMIdtftOCDQJANtEFIf7z5iQ6Um3l4rI65e4T8W6A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 617E068B05; Tue, 25 Nov 2025 12:31:44 +0100 (CET) Date: Tue, 25 Nov 2025 12:31:44 +0100 From: Christoph Hellwig To: Caleb Sander Mateos Cc: Keith Busch , Keith Busch , linux-block@vger.kernel.org, axboe@kernel.dk, hch@lst.de, ebiggers@kernel.org, "Martin K. Petersen" Subject: Re: [PATCHv6] blk-integrity: support arbitrary buffer alignment Message-ID: <20251125113144.GA22938@lst.de> References: <20251124161707.3491456-1-kbusch@meta.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) On Mon, Nov 24, 2025 at 07:41:16PM -0800, Caleb Sander Mateos wrote: > > Compare kmap_local_page() with kmap_local_folio(). They both resolve to > > the same lower level mapping function, and folios have no problem > > spanning pages. > > Documentation/mm/highmem.rst seems to suggest that kmap_local_folio() > only maps the page that contains the specified offset, not the whole > folio: Yes. Additionally multi-page bvecs aren't folios, they just are physically contiguous ranges. So I don't think we could even use any folio helpers if they worked, as a single range might consist of multiple folios. (Sorry for not spotting this earlier)