From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751680AbeBWIgc (ORCPT ); Fri, 23 Feb 2018 03:36:32 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:60828 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751273AbeBWIgb (ORCPT ); Fri, 23 Feb 2018 03:36:31 -0500 Date: Fri, 23 Feb 2018 16:36:19 +0800 From: Dave Young To: AKASHI Takahiro Cc: catalin.marinas@arm.com, will.deacon@arm.com, bauerman@linux.vnet.ibm.com, dhowells@redhat.com, vgoyal@redhat.com, herbert@gondor.apana.org.au, davem@davemloft.net, akpm@linux-foundation.org, mpe@ellerman.id.au, bhe@redhat.com, arnd@arndb.de, ard.biesheuvel@linaro.org, julien.thierry@arm.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Linus Torvalds Subject: Re: [PATCH v8 01/13] resource: add walk_system_ram_res_rev() Message-ID: <20180223083619.GA4433@dhcp-128-65.nay.redhat.com> References: <20180222111732.23051-1-takahiro.akashi@linaro.org> <20180222111732.23051-2-takahiro.akashi@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180222111732.23051-2-takahiro.akashi@linaro.org> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi AKASHI, On 02/22/18 at 08:17pm, AKASHI Takahiro wrote: > This function, being a variant of walk_system_ram_res() introduced in > commit 8c86e70acead ("resource: provide new functions to walk through > resources"), walks through a list of all the resources of System RAM > in reversed order, i.e., from higher to lower. > > It will be used in kexec_file implementation on arm64. I remember there was an old discussion about this, it should be added in patch log why this is needed. > > Signed-off-by: AKASHI Takahiro > Cc: Vivek Goyal > Cc: Andrew Morton > Cc: Linus Torvalds > --- > include/linux/ioport.h | 3 +++ > kernel/resource.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 60 insertions(+) > > diff --git a/include/linux/ioport.h b/include/linux/ioport.h > index da0ebaec25f0..f12d95fe038b 100644 > --- a/include/linux/ioport.h > +++ b/include/linux/ioport.h > @@ -277,6 +277,9 @@ extern int > walk_system_ram_res(u64 start, u64 end, void *arg, > int (*func)(struct resource *, void *)); > extern int > +walk_system_ram_res_rev(u64 start, u64 end, void *arg, > + int (*func)(struct resource *, void *)); > +extern int > walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, > void *arg, int (*func)(struct resource *, void *)); > > diff --git a/kernel/resource.c b/kernel/resource.c > index e270b5048988..bdaa93407f4c 100644 > --- a/kernel/resource.c > +++ b/kernel/resource.c > @@ -23,6 +23,8 @@ > #include > #include > #include > +#include > +#include > #include > > > @@ -486,6 +488,61 @@ int walk_mem_res(u64 start, u64 end, void *arg, > arg, func); > } > > +int walk_system_ram_res_rev(u64 start, u64 end, void *arg, > + int (*func)(struct resource *, void *)) > +{ > + struct resource res, *rams; > + int rams_size = 16, i; > + int ret = -1; > + > + /* create a list */ > + rams = vmalloc(sizeof(struct resource) * rams_size); > + if (!rams) > + return ret; > + > + res.start = start; > + res.end = end; > + res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > + i = 0; > + while ((res.start < res.end) && > + (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) { > + if (i >= rams_size) { > + /* re-alloc */ > + struct resource *rams_new; > + int rams_new_size; > + > + rams_new_size = rams_size + 16; > + rams_new = vmalloc(sizeof(struct resource) > + * rams_new_size); > + if (!rams_new) > + goto out; > + > + memcpy(rams_new, rams, > + sizeof(struct resource) * rams_size); > + vfree(rams); > + rams = rams_new; > + rams_size = rams_new_size; > + } > + > + rams[i].start = res.start; > + rams[i++].end = res.end; > + > + res.start = res.end + 1; > + res.end = end; > + } > + > + /* go reverse */ > + for (i--; i >= 0; i--) { > + ret = (*func)(&rams[i], arg); > + if (ret) > + break; > + } > + > +out: > + vfree(rams); > + return ret; > +} > + > #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) > > /* > -- > 2.16.2 > Thanks Dave