From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: semantics of dma_map_single() Date: Mon, 17 Jul 2017 08:42:20 +0200 Message-ID: <20170717064220.GA15807@lst.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Vineet Gupta Cc: "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , Christoph Hellwig , bart.vanassche@sandisk.com, Alexander Duyck , Krzysztof Kozlowski , Andrew Morton , lkml , arcml List-Id: linux-arch.vger.kernel.org I would expect that it would support any contiguous range in the kernel mapping (e.g. no vmalloc and friends). But it's not documented anywhere, and if no in kernel users makes use of that fact at the moment it might be better to document a page size limitation and add asserts to enforce it. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:49594 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253AbdGQGmW (ORCPT ); Mon, 17 Jul 2017 02:42:22 -0400 Date: Mon, 17 Jul 2017 08:42:20 +0200 From: Christoph Hellwig Subject: Re: semantics of dma_map_single() Message-ID: <20170717064220.GA15807@lst.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Vineet Gupta Cc: "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , Christoph Hellwig , bart.vanassche@sandisk.com, Alexander Duyck , Krzysztof Kozlowski , Andrew Morton , lkml , arcml Message-ID: <20170717064220.8mkkLBJ3exp_15qun5mkPt8RjWwhkb6Jzi0Xakw743o@z> I would expect that it would support any contiguous range in the kernel mapping (e.g. no vmalloc and friends). But it's not documented anywhere, and if no in kernel users makes use of that fact at the moment it might be better to document a page size limitation and add asserts to enforce it.