From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ve0-f176.google.com (mail-ve0-f176.google.com [209.85.128.176]) by kanga.kvack.org (Postfix) with ESMTP id 161B56B004D for ; Mon, 12 May 2014 21:45:09 -0400 (EDT) Received: by mail-ve0-f176.google.com with SMTP id jz11so9878668veb.35 for ; Mon, 12 May 2014 18:45:08 -0700 (PDT) Received: from mail-vc0-x242.google.com (mail-vc0-x242.google.com [2607:f8b0:400c:c03::242]) by mx.google.com with ESMTPS id uv3si2375839vdc.95.2014.05.12.18.45.08 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 12 May 2014 18:45:08 -0700 (PDT) Received: by mail-vc0-f194.google.com with SMTP id hr9so1767621vcb.9 for ; Mon, 12 May 2014 18:45:08 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <5146762.jba3IJe7xt@wuerfel> References: <1399861195-21087-1-git-send-email-superlibj8301@gmail.com> <1399861195-21087-3-git-send-email-superlibj8301@gmail.com> <5146762.jba3IJe7xt@wuerfel> Date: Tue, 13 May 2014 09:45:08 +0800 Message-ID: Subject: Re: [RFC][PATCH 2/2] ARM: ioremap: Add IO mapping space reused support. From: Richard Lee Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, linux@arm.linux.org.uk, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Richard Lee > On Mon, May 12, 2014 at 3:51 PM, Arnd Bergmann wrote: > On Monday 12 May 2014 10:19:55 Richard Lee wrote: >> For the IO mapping, for the same physical address space maybe >> mapped more than one time, for example, in some SoCs: >> 0x20000000 ~ 0x20001000: are global control IO physical map, >> and this range space will be used by many drivers. >> And then if each driver will do the same ioremap operation, we >> will waste to much malloc virtual spaces. >> >> This patch add IO mapping space reused support. >> >> Signed-off-by: Richard Lee > > What happens if the first driver then unmaps the area? > If the first driver will unmap the area, it shouldn't do any thing except decreasing the 'used' counter. Thanks, BRs Richard Lee > Arnd -- 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