From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 153E84657F5 for ; Wed, 5 Aug 2026 12:39:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785933546; cv=none; b=AgVJzLuAdQQWfx1Wl0i6aF4Z07aOrV8gcjm8mrivx1OY5mTLogPkaSVeHx0/hoNOG6USq27vGF5UwsdD08n51csQ2TLjOdZvBlBEkQUJzorKkQ4jJS6yuwhHILmRTbwHd2Mx5XPuf98IprH1IbeCasCirUybEnIrCXprDgAZNL8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785933546; c=relaxed/simple; bh=N5biFNBr62yZe8gEJEP404p720ir8MesthgLLy3nc+o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Uj7UnJFj85OTiZVO2g9ROhME+uTFGvmQ5bXELGGVCbcsdm9qoTiwZvKdQgyIYjY9FZUdLKsAFcu0xPRZXcZ5fbgIrbIrp4lIVQu15q8gtIXifKZXCJOkQv4QxLApTNB4j6MyQEnzd+zp6EXrZ0ntPS+2puGymova8j+a49nWuXI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com; spf=none smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.198]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4hFVLj2GCyzYQvVd for ; Wed, 5 Aug 2026 20:38:05 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.252]) by mail.maildlp.com (Postfix) with ESMTP id 571C84087D for ; Wed, 5 Aug 2026 20:38:58 +0800 (CST) Received: from huaweicloud.com (unknown [10.50.85.155]) by APP3 (Coremail) with UTF8SMTPSA id _Ch0CgC3pkXfLnNqRJjWBA--.10386S5; Wed, 05 Aug 2026 20:38:58 +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 v8 1/8] nbd: simplify find_fallback() by removing redundant logic Date: Wed, 5 Aug 2026 20:29:23 +0800 Message-ID: <20260805122930.57647-2-yangerkun@huawei.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260805122930.57647-1-yangerkun@huawei.com> References: <20260805122930.57647-1-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:_Ch0CgC3pkXfLnNqRJjWBA--.10386S5 X-Coremail-Antispam: 1UD129KBjvJXoW7Kr15ur1kWrW8uw1UKr45ZFb_yoW8tF1UpF WfZFyfKryUXF13ur43Za1UuF1rCws3Ga1UGFW8Ja4xuryDCryUuFZ3tF1ftayUJrZxZF9F vF1UGFy2kFn8Cw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUmvb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUGw A2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWUCVW8JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV WxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVWxJr0_GcWl84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AFwI 0_Jw0_GFyl42xK82IYc2Ij64vIr41l42xK82IY64kExVAvwVAq07x20xyl4I8I3I0E4IkC 6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWw C2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_ JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJV WUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E14v26r4UJVWxJrUv cSsGvfC2KfnxnUUI43ZEXa7IU8epB3UUUUU== 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. Reviewed-by: Yu Kuai Signed-off-by: Long Li --- 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