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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DDC66C7EE37 for ; Sat, 27 May 2023 12:36:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Zij9UW8CaM7T9eSxBbq/JyfIHmsxov9Qof+or7HTQh4=; b=xgHknL+g8O20p7 YzwZUe7sAgz2usxq8BC2341WR29xxfNeZJ7CC4ax6O9ypJSl4EnMAuURH5inuUpdZsbcX1iuby2/e LbrIMuqFSUy1BbJZSTtR4/yEVUeYH7PijrzdJ4Wh2x6i6oIDvIxMqzP2MyTPKvtpPiNH7OF87FVnX /xb1sXeig40rXE0Gut38NWfJzb31Y802b/sxvlh2s4+JHj3k488T0j/QvJWWiztmLhNoHB60HJQQX 0XltqGQNJ2u0zp5xQKQq7WYLWnlPuR7SI6i7Mr4h4Ji2NGjQT+3R+v3mRPcaJPeys73omOxHELPDq vpxZu2Lx51wj//YFZ5Xw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q2t9R-005ioZ-0y; Sat, 27 May 2023 12:36:05 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q2t9L-005ijN-2F for kexec@lists.infradead.org; Sat, 27 May 2023 12:36:01 +0000 Received: from dggpemm500006.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4QT1Nz25QszqScm; Sat, 27 May 2023 20:31:15 +0800 (CST) Received: from thunder-town.china.huawei.com (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Sat, 27 May 2023 20:35:48 +0800 From: Zhen Lei To: Eric Biederman , Baoquan He , , CC: Zhen Lei , Michael Holzheu , Andrew Morton , Amerigo Wang Subject: [PATCH 4/6] kexec: improve the readability of crash_shrink_memory() Date: Sat, 27 May 2023 20:34:37 +0800 Message-ID: <20230527123439.772-5-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.37.3.windows.1 In-Reply-To: <20230527123439.772-1-thunder.leizhen@huawei.com> References: <20230527123439.772-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230527_053559_919859_E6459859 X-CRM114-Status: GOOD ( 12.82 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org The major adjustments are: 1. end = start + new_size. The 'end' here is not an accurate representation, because it is not the new end of crashk_res, but the start of ram_res, difference 1. So eliminate it and replace it with ram_res->start. 2. Use 'ram_res->start' and 'ram_res->end' as arguments to crash_free_reserved_phys_range() to indicate that the memory covered by 'ram_res' is released from the crashk. And keep it close to insert_resource(). 3. Replace 'if (start == end)' with 'if (!new_size)', clear indication that all crashk memory will be shrunken. No functional change. Signed-off-by: Zhen Lei --- kernel/kexec_core.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index bcc86a250ab3bf9..69fe92141b0b62d 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1108,7 +1108,6 @@ ssize_t crash_get_memory_size(void) int crash_shrink_memory(unsigned long new_size) { int ret = 0; - unsigned long start, end; unsigned long old_size; struct resource *ram_res; @@ -1119,9 +1118,7 @@ int crash_shrink_memory(unsigned long new_size) ret = -ENOENT; goto unlock; } - start = crashk_res.start; - end = crashk_res.end; - old_size = (end == 0) ? 0 : end - start + 1; + old_size = !crashk_res.end ? 0 : resource_size(&crashk_res); new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN); if (new_size >= old_size) { ret = (new_size == old_size) ? 0 : -EINVAL; @@ -1134,22 +1131,20 @@ int crash_shrink_memory(unsigned long new_size) goto unlock; } - end = start + new_size; - crash_free_reserved_phys_range(end, crashk_res.end); - - ram_res->start = end; + ram_res->start = crashk_res.start + new_size; ram_res->end = crashk_res.end; ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM; ram_res->name = "System RAM"; - if (start == end) { + if (!new_size) { release_resource(&crashk_res); crashk_res.start = 0; crashk_res.end = 0; } else { - crashk_res.end = end - 1; + crashk_res.end = ram_res->start - 1; } + crash_free_reserved_phys_range(ram_res->start, ram_res->end); insert_resource(&iomem_resource, ram_res); unlock: -- 2.25.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec