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 X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A21D5C433E0 for ; Mon, 22 Feb 2021 05:02:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 61D7664E76 for ; Mon, 22 Feb 2021 05:02:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61D7664E76 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=phytium.com.cn Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A64866B006C; Mon, 22 Feb 2021 00:02:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A14DE6B0070; Mon, 22 Feb 2021 00:02:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 92BAB6B0071; Mon, 22 Feb 2021 00:02:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0043.hostedemail.com [216.40.44.43]) by kanga.kvack.org (Postfix) with ESMTP id 7CE5E6B006C for ; Mon, 22 Feb 2021 00:02:56 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 336F8908E for ; Mon, 22 Feb 2021 05:02:56 +0000 (UTC) X-FDA: 77844709152.17.C4B558E Received: from azure-sdnproxy-1.icoremail.net (azure-sdnproxy.icoremail.net [52.187.6.220]) by imf26.hostedemail.com (Postfix) with SMTP id AAA37407F8FA for ; Mon, 22 Feb 2021 05:02:46 +0000 (UTC) Received: from centos7u5.localdomain (unknown [202.43.158.76]) by c1app2 (Coremail) with SMTP id AgINCgDn7Ey0OjNgVh0UAw--.24169S3; Mon, 22 Feb 2021 13:01:40 +0800 (CST) From: Zhiyuan Dai To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zhiyuan Dai Subject: [PATCH] mm/ioremap: remove volatile keyword in iounmap function Date: Mon, 22 Feb 2021 13:01:35 +0800 Message-Id: <1613970095-22577-1-git-send-email-daizhiyuan@phytium.com.cn> X-Mailer: git-send-email 1.8.3.1 X-CM-TRANSID:AgINCgDn7Ey0OjNgVh0UAw--.24169S3 X-Coremail-Antispam: 1UD129KBjvdXoWrKFykWF1DXF43WrW3Xr1fWFg_yoWDCrg_Za 4jgFW8Kas8tas3Zr1j9F4furnYvw4q9r4vvrWxuFyft3s8JFnxJF4Dur9rXr15Xw4vvry3 Wr4FqrW3Cr4avjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbckFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8w A2z4x0Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Jr0_ Gr1l84ACjcxK6I8E87Iv67AKxVWxJr0_GcWl84ACjcxK6I8E87Iv6xkF7I0E14v26F4UJV W0owAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY02Avz4vE14v_GrWl 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r 4UMIIF0xvE42xK8VAvwI8IcIk0rVWrZr1j6s0DMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF 0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JU4a09UUUUU= X-Originating-IP: [202.43.158.76] X-CM-SenderInfo: hgdl6xpl1xt0o6sk53xlxphulrpou0/ X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: AAA37407F8FA X-Stat-Signature: rc379c48woyonrzzze69537gjdrxjdm8 Received-SPF: none (phytium.com.cn>: No applicable sender policy available) receiver=imf26; identity=mailfrom; envelope-from=""; helo=azure-sdnproxy-1.icoremail.net; client-ip=52.187.6.220 X-HE-DKIM-Result: none/none X-HE-Tag: 1613970166-764154 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000032, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Like volatile, the kernel primitives which make concurrent access to data safe (spinlocks, mutexes, memory barriers, etc.) are designed to prevent unwanted optimization. If they are being used properly, there will be no need to use volatile as well. If volatile is still necessary, there is almost certainly a bug in the code somewhere. In properly-written kernel code, volatile can only serve to slow things down. see: Documentation/process/volatile-considered-harmful.rst Signed-off-by: Zhiyuan Dai --- mm/ioremap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/ioremap.c b/mm/ioremap.c index 5fa1ab4..c49dd41 100644 --- a/mm/ioremap.c +++ b/mm/ioremap.c @@ -281,7 +281,7 @@ void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot) } EXPORT_SYMBOL(ioremap_prot); -void iounmap(volatile void __iomem *addr) +void iounmap(void __iomem *addr) { vunmap((void *)((unsigned long)addr & PAGE_MASK)); } -- 1.8.3.1