From nobody Wed Sep 17 19:24:37 2025 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 9783AC4332F for ; Fri, 16 Dec 2022 04:24:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229793AbiLPEYa (ORCPT ); Thu, 15 Dec 2022 23:24:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229762AbiLPEYE (ORCPT ); Thu, 15 Dec 2022 23:24:04 -0500 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A17E45FB9A for ; Thu, 15 Dec 2022 20:24:01 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4NYGFR3QPHz4f3kLC for ; Fri, 16 Dec 2022 12:23:55 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgD3Z9Xc8ptj4ChDCQ--.22309S4; Fri, 16 Dec 2022 12:23:58 +0800 (CST) From: Hou Tao To: dm-devel@redhat.com Cc: Alasdair Kergon , Mike Snitzer , linux-kernel@vger.kernel.org, houtao1@huawei.com Subject: [PATCH] dm: remove unnecessary check when using dm_get_mdptr() Date: Fri, 16 Dec 2022 12:23:53 +0800 Message-Id: <20221216042353.3132139-1-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgD3Z9Xc8ptj4ChDCQ--.22309S4 X-Coremail-Antispam: 1UD129KBjvJXoW7uw4DKFWUArWkJF1DGr4fuFg_yoW8AF4Dpr 4YgrWavrykJFsFgr4jvanxuF90gw1Yk3yUGryIk34Y93W5u3WUWay5GF92qFyrKFZ7AFWY gF1Ig3y5AF4DJwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUgCb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Cr0_Gr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I 0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Y z7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zV AF1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4l IxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWrZr1j6s 0DMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Jr0_GrUvcSsG vfC2KfnxnUUI43ZEXa7IU1zuWJUUUUU== X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Hou Tao __hash_remove() removes hash_cell with _hash_lock locked, so acquiring _hash_lock can guarantee no-NULL hc returned from dm_get_mdptr() must have not been removed and hc->md must still be md. __hash_remove() also acquires dm_hash_cells_mutex before setting mdptr as NULL, so in dm_copy_name_and_uuid() after acquiring dm_hash_cells_mutex and ensuring returned hc is not NULL, the returned hc must still be alive and hc->md must still be md. So removing these unnecessary hc->md !=3D md checks when using dm_get_mdptr() with _hash_lock or dm_hash_cells_mutex acquired. Signed-off-by: Hou Tao --- drivers/md/dm-ioctl.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 3bfc1583c20a..2a86524661d1 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -772,7 +772,7 @@ static struct dm_table *dm_get_inactive_table(struct ma= pped_device *md, int *src =20 down_read(&_hash_lock); hc =3D dm_get_mdptr(md); - if (!hc || hc->md !=3D md) { + if (!hc) { DMERR("device has been removed from the dev hash table."); goto out; } @@ -1476,7 +1476,7 @@ static int table_load(struct file *filp, struct dm_io= ctl *param, size_t param_si /* stage inactive table */ down_write(&_hash_lock); hc =3D dm_get_mdptr(md); - if (!hc || hc->md !=3D md) { + if (!hc) { DMERR("device has been removed from the dev hash table."); up_write(&_hash_lock); r =3D -ENXIO; @@ -2128,7 +2128,7 @@ int dm_copy_name_and_uuid(struct mapped_device *md, c= har *name, char *uuid) =20 mutex_lock(&dm_hash_cells_mutex); hc =3D dm_get_mdptr(md); - if (!hc || hc->md !=3D md) { + if (!hc) { r =3D -ENXIO; goto out; } --=20 2.29.2