From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 48ED73B9D8D for ; Thu, 30 Jul 2026 08:29:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785400203; cv=none; b=YsQyVLJf4EOpKvmIu+l1fVYbkl2mxk9fQBoEPf/JRZ6jPVXiXj7Jy6xarqiJgvjUUeT4y73FaOriGaR/0CiMOA3CzdrAiP3h5/i34lkoldtAqrF75mFMhdLskHjIrjmK4TTCRgl00qfT+ylHECVG6enkBzmxEZ1B7s5o+YjLvc8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785400203; c=relaxed/simple; bh=kv6a6LxiTWXL5U2GgJxzrIpyqlsIMoi3BKGbxX/asTM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Md3D22fbVYK3EbSYER4tj1kPKDd6iSfRKRqBagmtackmDpwwqkYEPmwcwi/+ybwgcDIvz0zHokhpKiz0QVHvOgRu6pVIrzctkJIdoNU0krs2gZmXE9T4CgSOCiZCBYOmWE4TfCQYjg9TdvoqlBjoxo9zl9+Lyqu6c6kG+ReAjCo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.170]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4h9j620xJYzKHMgL for ; Thu, 30 Jul 2026 16:28:58 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.252]) by mail.maildlp.com (Postfix) with ESMTP id 88D5B40575 for ; Thu, 30 Jul 2026 16:29:54 +0800 (CST) Received: from huaweicloud.com (unknown [10.50.85.155]) by APP3 (Coremail) with UTF8SMTPSA id _Ch0CgCnlkV9C2tqwObjAQ--.20420S5; Thu, 30 Jul 2026 16:29:54 +0800 (CST) From: Yang Erkun To: josef@toxicpanda.com, axboe@kernel.dk, hch@lst.de, yukuai@kernel.org Cc: yi.zhang@huawei.com, chengzhihao1@huawei.com, echo.chenlin@huawei.com, leo.lilong@huaweicloud.com, wangkefeng.wang@huawei.com, huawei.libin@huawei.com, leijitang@huawei.com, linux-block@vger.kernel.org, nbd@other.debian.org Subject: [PATCH v5 1/8] nbd: simplify find_fallback() by removing redundant logic Date: Thu, 30 Jul 2026 16:20:39 +0800 Message-ID: <20260730082046.3459239-2-yangerkun@huawei.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260730082046.3459239-1-yangerkun@huawei.com> References: <20260730082046.3459239-1-yangerkun@huawei.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_Ch0CgCnlkV9C2tqwObjAQ--.20420S5 X-Coremail-Antispam: 1UD129KBjvJXoW7Kr15ur1kWrW8uw1UKr45ZFb_yoW8tF1UpF WfZFyfKryUXF13uF43Za1UuF1rCan3Ga1UGFW8Ja4xuryDCryUuFZ3tF1ftayUJrZxZF9F vF1UGFy2kFn8Cw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUmmb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUGw A2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV WxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ew Av7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY 6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS14 v26r1q6r43MxAIw28IcxkI7VAKI48JMxAIw28IcVAKzI0EY4vE52x082I5MxC20s026xCa FVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_Jr Wlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j 6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr 0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1U YxBIdaVFxhVjvjDU0xZFpf9x07jnWrAUUUUU= Sender: yangerkun@huaweicloud.com X-CM-SenderInfo: 51dqwvhunx0q5kxd4v5lfo033gof0z/ From: Long Li The second conditional checking nsock->fallback_index validity is the logical inverse of the first, so drop it and let execution fall through naturally. Consolidate the two identical dev_err_ratelimited() + return paths into a single no_fallback label to reduce duplication. Signed-off-by: Long Li Reviewed-by: Yu Kuai --- drivers/block/nbd.c | 37 ++++++++++++++----------------------- 1 file changed, 14 insertions(+), 23 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 8f10762e90ef..b1a5acd57426 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1061,40 +1061,31 @@ static int find_fallback(struct nbd_device *nbd, int index) int new_index = -1; struct nbd_sock *nsock = config->socks[index]; int fallback = nsock->fallback_index; + int i; if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags)) return new_index; - if (config->num_connections <= 1) { - dev_err_ratelimited(disk_to_dev(nbd->disk), - "Dead connection, failed to find a fallback\n"); - return new_index; - } + if (config->num_connections <= 1) + goto no_fallback; if (fallback >= 0 && fallback < config->num_connections && !config->socks[fallback]->dead) return fallback; - if (nsock->fallback_index < 0 || - nsock->fallback_index >= config->num_connections || - config->socks[nsock->fallback_index]->dead) { - int i; - for (i = 0; i < config->num_connections; i++) { - if (i == index) - continue; - if (!config->socks[i]->dead) { - new_index = i; - break; - } - } - nsock->fallback_index = new_index; - if (new_index < 0) { - dev_err_ratelimited(disk_to_dev(nbd->disk), - "Dead connection, failed to find a fallback\n"); - return new_index; + for (i = 0; i < config->num_connections; i++) { + if (i != index && !config->socks[i]->dead) { + new_index = i; + break; } } - new_index = nsock->fallback_index; + nsock->fallback_index = new_index; + if (new_index >= 0) + return new_index; + +no_fallback: + dev_err_ratelimited(disk_to_dev(nbd->disk), + "Dead connection, failed to find a fallback\n"); return new_index; } -- 2.52.0