From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 350D5C4167D for ; Wed, 15 Nov 2023 00:41:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234239AbjKOAlI (ORCPT ); Tue, 14 Nov 2023 19:41:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234221AbjKOAlF (ORCPT ); Tue, 14 Nov 2023 19:41:05 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACA9BDC for ; Tue, 14 Nov 2023 16:41:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1700008860; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=STT+ATW57rth6ZYo472RqzwfiLTSlBKOqun91LfAKSQ=; b=Meu3KzsBWv4UAB5vFCvO5/XTIFW+WL+gEqRRZAeNP/Ty9eZkHC9ev1ZvCsLu0j5EH1nIyb hUGAyUmsNh/6MqCbg9q4NpLUhIGnna6t+XELC/RIpZSc0ra/EuD1zGpwKR9G5gUrXxqovE z/CkrJSCBpA9lLVoJBR6AyCfpsirxWM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-154-77tfofzDNhCK4KwggBC1CQ-1; Tue, 14 Nov 2023 19:40:55 -0500 X-MC-Unique: 77tfofzDNhCK4KwggBC1CQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 04645185A780; Wed, 15 Nov 2023 00:40:55 +0000 (UTC) Received: from localhost (unknown [10.72.112.9]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D0446112130B; Wed, 15 Nov 2023 00:40:53 +0000 (UTC) Date: Wed, 15 Nov 2023 08:40:50 +0800 From: Baoquan He To: Andrew Morton Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, x86@kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, ebiederm@xmission.com, takahiro.akashi@linaro.org Subject: Re: [PATCH 1/2] resource: add walk_system_ram_res_rev() Message-ID: References: <20231114091658.228030-1-bhe@redhat.com> <20231114091658.228030-2-bhe@redhat.com> <20231114151745.e77ed504b3fce325f54ec08e@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231114151745.e77ed504b3fce325f54ec08e@linux-foundation.org> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/14/23 at 03:17pm, Andrew Morton wrote: > On Tue, 14 Nov 2023 17:16:57 +0800 Baoquan He 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 code to load kernel, initrd etc when > > preparing kexec reboot. > > > > ... > > > > +/* > > + * This function, being a variant of walk_system_ram_res(), calls the @func > > + * callback against all memory ranges of type System RAM which are marked as > > + * IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY in reversed order, i.e., from > > + * higher to lower. > > + */ > > +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; > > + unsigned long flags; > > + int ret = -1; > > + > > + /* create a list */ > > + rams = kvcalloc(rams_size, sizeof(struct resource), GFP_KERNEL); > > + if (!rams) > > + return ret; > > + > > + flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > > + i = 0; > > + while ((start < end) && > > + (!find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res))) { > > + if (i >= rams_size) { > > + /* re-alloc */ > > + struct resource *rams_new; > > + int rams_new_size; > > + > > + rams_new_size = rams_size + 16; > > + rams_new = kvcalloc(rams_new_size, sizeof(struct resource), > > + GFP_KERNEL); > > kvrealloc()? Exactly. Will udpate. Thanks for the great suggestion. > > > + if (!rams_new) > > + goto out; > > + > > + memcpy(rams_new, rams, > > + sizeof(struct resource) * rams_size); > > + kvfree(rams); > > + rams = rams_new; > > + rams_size = rams_new_size; > > + } > > + > > + rams[i].start = res.start; > > + rams[i++].end = res.end; > > + > > + start = res.end + 1; > > + } > > + > > + /* go reverse */ > > + for (i--; i >= 0; i--) { > > + ret = (*func)(&rams[i], arg); > > + if (ret) > > + break; > > + } > > + > > +out: > > + kvfree(rams); > > + return ret; > > +} > > + > > /* > > * This function calls the @func callback against all memory ranges, which > > * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY. > > -- > > 2.41.0 >