From: "Stephen C. Tweedie" <sct@redhat.com>
To: Timur Tabi <ttabi@interactivesi.com>
Cc: "Stephen C. Tweedie" <sct@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: ioremap_nocache problem?
Date: Fri, 26 Jan 2001 10:37:14 +0000 [thread overview]
Message-ID: <20010126103714.B11607@redhat.com> (raw)
In-Reply-To: <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>
In-Reply-To: <200101251556.f0PFuPd01743@mail.redhat.com>; from ttabi@interactivesi.com on Thu, Jan 25, 2001 at 09:56:32AM -0600
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
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WARNING: multiple messages have this Message-ID (diff)
From: "Stephen C. Tweedie" <sct@redhat.com>
To: Timur Tabi <ttabi@interactivesi.com>
Cc: "Stephen C. Tweedie" <sct@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: ioremap_nocache problem?
Date: Fri, 26 Jan 2001 10:37:14 +0000 [thread overview]
Message-ID: <20010126103714.B11607@redhat.com> (raw)
In-Reply-To: <200101251556.f0PFuPd01743@mail.redhat.com>; from ttabi@interactivesi.com on Thu, Jan 25, 2001 at 09:56:32AM -0600
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/
next prev parent reply other threads:[~2001-01-26 10:40 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-01-23 10:30 ioremap_nocache problem? Mark Mokryn
2001-01-23 10:30 ` Mark Mokryn
2001-01-23 16:53 ` Timur Tabi
2001-01-25 15:16 ` Stephen C. Tweedie
2001-01-25 15:16 ` Stephen C. Tweedie
2001-01-25 15:56 ` Timur Tabi
2001-01-25 16:44 ` Roman Zippel
2001-01-25 16:44 ` Roman Zippel
2001-01-25 16:49 ` Timur Tabi
2001-01-26 10:39 ` Stephen C. Tweedie
2001-01-26 10:39 ` Stephen C. Tweedie
2001-01-25 16:49 ` Timur Tabi
2001-01-25 17:04 ` Jeff Hartmann
2001-01-25 17:04 ` Jeff Hartmann
2001-01-25 17:11 ` Timur Tabi
2001-01-25 17:11 ` Timur Tabi
[not found] ` <E14LpvQ-0008Pw-00@mail.valinux.com>
2001-01-25 17:47 ` Jeff Hartmann
2001-01-25 17:47 ` Jeff Hartmann
2001-01-25 17:53 ` Timur Tabi
2001-01-26 10:43 ` Stephen C. Tweedie
2001-01-26 10:43 ` Stephen C. Tweedie
2001-01-26 16:32 ` Eric W. Biederman
2001-01-26 19:22 ` Timur Tabi
2001-01-25 17:53 ` Timur Tabi
2001-01-25 18:13 ` Jeff Hartmann
2001-01-25 18:13 ` Jeff Hartmann
2001-01-25 18:18 ` Timur Tabi
2001-01-25 18:18 ` Timur Tabi
[not found] ` <E14Lqyt-0003z6-00@mail.valinux.com>
2001-01-25 18:46 ` Jeff Hartmann
2001-01-25 18:46 ` Jeff Hartmann
[not found] ` <200101251556.f0PFuPd01743@mail.redhat.com>
2001-01-26 10:37 ` Stephen C. Tweedie [this message]
2001-01-26 10:37 ` Stephen C. Tweedie
2001-01-25 15:56 ` Timur Tabi
2001-01-23 16:53 ` Timur Tabi
2001-01-23 18:12 ` Roman Zippel
2001-01-23 18:12 ` Roman Zippel
2001-01-23 18:38 ` Timur Tabi
2001-01-24 0:50 ` David Wragg
2001-01-24 0:50 ` David Wragg, David Wragg
2001-01-24 15:14 ` Timur Tabi
2001-01-24 15:14 ` Timur Tabi
[not found] ` <E14LRce-0008FU-00@diver.doc.ic.ac.uk>
2001-01-24 15:39 ` David Wragg
2001-01-24 15:39 ` David Wragg
2001-01-23 18:38 ` Timur Tabi
2001-01-24 1:01 ` David Wragg
2001-01-24 1:01 ` David Wragg
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