From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 26 Jan 2001 10:37:14 +0000 From: "Stephen C. Tweedie" Subject: Re: ioremap_nocache problem? Message-ID: <20010126103714.B11607@redhat.com> References: <3A6D5D28.C132D416@sangate.com> <20010123165117Z131182-221+34@kanga.kvack.org> <20010123165117Z131182-221+34@kanga.kvack.org> <20010125151655.V11607@redhat.com> <200101251556.f0PFuPd01743@mail.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200101251556.f0PFuPd01743@mail.redhat.com>; from ttabi@interactivesi.com on Thu, Jan 25, 2001 at 09:56:32AM -0600 Sender: owner-linux-mm@kvack.org Return-Path: To: Timur Tabi Cc: "Stephen C. Tweedie" , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: Hi, On Thu, Jan 25, 2001 at 09:56:32AM -0600, Timur Tabi wrote: > > ioremap*() is only supposed to be used on IO regions or reserved > > pages. If you haven't marked the pages as reserved, then iounmap will > > do the wrong thing, so it's up to you to reserve the pages. > > Au contraire! > > I mark the page as reserved when I ioremap() it. However, if I leave it marked > reserved, then iounmap() will not unmap it. It certainly should do, and the 2.4 source certainly looks as if it does. At least on i386, iounmap calls vfree, which ends up in free_area_pte(), which will unconditionally clear the pte (hence unmapping the page). Cheers, Stephen -- 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.eu.org/Linux-MM/