From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966454AbcA1Kcd (ORCPT ); Thu, 28 Jan 2016 05:32:33 -0500 Received: from e06smtp13.uk.ibm.com ([195.75.94.109]:55907 "EHLO e06smtp13.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965960AbcA1KcY (ORCPT ); Thu, 28 Jan 2016 05:32:24 -0500 X-IBM-Helo: d06dlp03.portsmouth.uk.ibm.com X-IBM-MailFrom: holzheu@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-s390@vger.kernel.org Date: Thu, 28 Jan 2016 11:32:17 +0100 From: Michael Holzheu To: Andrew Morton Cc: Dmitry Safonov , , , , , , , , <0x7f454c46@gmail.com>, Xunlei Pang Subject: Re: [PATCH] kexec: unmap reserved pages for each error-return way Message-ID: <20160128113217.79d37ff5@holzheu> In-Reply-To: <20160127111546.2212f191f5f313b613f6b60b@linux-foundation.org> References: <1453895311-11087-1-git-send-email-dsafonov@virtuozzo.com> <20160127111546.2212f191f5f313b613f6b60b@linux-foundation.org> Organization: IBM X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16012810-0013-0000-0000-0000086FEA6C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 27 Jan 2016 11:15:46 -0800 Andrew Morton wrote: > On Wed, 27 Jan 2016 14:48:31 +0300 Dmitry Safonov wrote: > > > For allocation of kimage failure or kexec_prepare or load segments > > errors there is no need to keep crashkernel memory mapped. > > It will affect only s390 as map/unmap hook defined only for it. > > As on unmap s390 also changes os_info structure let's check return code > > and add info only on success. > > > > This conflicts (both mechanically and somewhat conceptually) with > Xunlei Pang's "kexec: Introduce a protection mechanism for the > crashkernel reserved memory" and "kexec: provide > arch_kexec_protect(unprotect)_crashkres()". > > http://ozlabs.org/~akpm/mmots/broken-out/kexec-introduce-a-protection-mechanism-for-the-crashkernel-reserved-memory.patch > http://ozlabs.org/~akpm/mmots/broken-out/kexec-introduce-a-protection-mechanism-for-the-crashkernel-reserved-memory-v4.patch > > and > > http://ozlabs.org/~akpm/mmots/broken-out/kexec-provide-arch_kexec_protectunprotect_crashkres.patch > http://ozlabs.org/~akpm/mmots/broken-out/kexec-provide-arch_kexec_protectunprotect_crashkres-v4.patch Hmm, It looks to me that arch_kexec_(un)protect_crashkres() has exactly the same semantics as crash_(un)map_reserved_pages(). On s390 we don't have the crashkernel memory mapped and therefore need crash_map_reserved_pages() before loading something into crashkernel memory. Perhaps I missed something? Michael