Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753820AbdIHCcF (ORCPT ); Thu, 7 Sep 2017 22:32:05 -0400 Received: from mail-pg0-f41.google.com ([74.125.83.41]:34997 "EHLO mail-pg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752093AbdIHCcE (ORCPT ); Thu, 7 Sep 2017 22:32:04 -0400 X-Google-Smtp-Source: ADKCNb6cVCnJRAfZeSRJUTcJg2TtQj+t5jlG241zs2FN/oo3XhJ0xH6S22qk1nbppxLjtJJEKPoVKQ== Date: Fri, 8 Sep 2017 11:33:47 +0900 From: AKASHI Takahiro To: Pratyush Anand 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, dyoung@redhat.com, bhe@redhat.com, arnd@arndb.de, ard.biesheuvel@linaro.org, Linus Torvalds , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 03/14] resource: add walk_system_ram_res_rev() Message-ID: <20170908023347.GB17186@linaro.org> Mail-Followup-To: AKASHI Takahiro , Pratyush Anand , 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, dyoung@redhat.com, bhe@redhat.com, arnd@arndb.de, ard.biesheuvel@linaro.org, Linus Torvalds , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20170824081811.19299-1-takahiro.akashi@linaro.org> <20170824081811.19299-4-takahiro.akashi@linaro.org> <5b6a0f9a-839a-ed57-e78e-88dbc9a7361c@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5b6a0f9a-839a-ed57-e78e-88dbc9a7361c@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3163 Lines: 109 On Thu, Aug 31, 2017 at 08:04:51AM +0530, Pratyush Anand wrote: > > > On Thursday 24 August 2017 01:48 PM, 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. > > > >Signed-off-by: AKASHI Takahiro > >Cc: Vivek Goyal > >Cc: Andrew Morton > >Cc: Linus Torvalds > >--- > > include/linux/ioport.h | 3 +++ > > kernel/resource.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 51 insertions(+) > > > >diff --git a/include/linux/ioport.h b/include/linux/ioport.h > >index 6230064d7f95..9a212266299f 100644 > >--- a/include/linux/ioport.h > >+++ b/include/linux/ioport.h > >@@ -271,6 +271,9 @@ extern int > > walk_system_ram_res(u64 start, u64 end, void *arg, > > int (*func)(u64, u64, void *)); > > extern int > >+walk_system_ram_res_rev(u64 start, u64 end, void *arg, > >+ int (*func)(u64, u64, void *)); > >+extern int > > walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, > > void *arg, int (*func)(u64, u64, void *)); > >diff --git a/kernel/resource.c b/kernel/resource.c > >index 9b5f04404152..1d6d734c75ac 100644 > >--- a/kernel/resource.c > >+++ b/kernel/resource.c > >@@ -23,6 +23,7 @@ > > #include > > #include > > #include > >+#include > > #include > >@@ -469,6 +470,53 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, > > return ret; > > } > >+int walk_system_ram_res_rev(u64 start, u64 end, void *arg, > >+ int (*func)(u64, u64, void *)) > >+{ > >+ struct resource res, *rams; > >+ u64 orig_end; > >+ int count, i; > >+ int ret = -1; > >+ > >+ count = 16; /* initial */ > >+again: > >+ /* create a list */ > >+ rams = vmalloc(sizeof(struct resource) * count); > >+ if (!rams) > >+ return ret; > >+ > >+ res.start = start; > >+ res.end = end; > >+ res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > >+ orig_end = res.end; > >+ i = 0; > >+ while ((res.start < res.end) && > >+ (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) { > >+ if (i >= count) { > >+ /* unlikely but */ > >+ vfree(rams); > >+ count += 16; > >+ goto again; > > Wounld't it be better to re-alloc a bigger space,copy previous values and > free the previous pointer, instead of going *again*. Okey, I will do that. Thanks, -Takahiro AKASHI > >+ } > >+ > >+ rams[i].start = res.start; > >+ rams[i++].end = res.end; > >+ > >+ res.start = res.end + 1; > >+ res.end = orig_end; > >+ } > >+ > >+ /* go reverse */ > >+ for (i--; i >= 0; i--) { > >+ ret = (*func)(rams[i].start, rams[i].end, arg); > >+ if (ret) > >+ break; > >+ } > >+ > >+ vfree(rams); > >+ return ret; > >+} > >+ > > #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) > > /* > > > > -- > Regards > Pratyush