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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BED60C4167B for ; Tue, 28 Nov 2023 21:07:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346745AbjK1VHL (ORCPT ); Tue, 28 Nov 2023 16:07:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346614AbjK1VGi (ORCPT ); Tue, 28 Nov 2023 16:06:38 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3DE219BA for ; Tue, 28 Nov 2023 13:06:39 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76B61C433C9; Tue, 28 Nov 2023 21:06:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701205599; bh=ldiK7KuLUTDjHoUTrRv5GR28hpJAs7FlnaeFLTHn/uM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AD2hPT5xx2Bwf6lZlp/c+fcO5NUxuvSWifwH71NTsvBXV8SGI3QF+ZVIw385tN+WI aJBy643deBaLZKcsBB8o5z/1Qld5TCdV9KdYiHndaa8HPcNqhKfUVM5BoM79TqFeke cUqcs8SqO0AS4Z5Sn4tMduwljRaEXw359x24BzPDu7EM1k6QnX9dygDV8FTvwDWDKD USrFSp2YzQNcQ6f8D6Qmd+foMCJ6YZN1cans8E1I5IcC6qVkpZDFJ0qQM/xRu4UBvP jEvUTdjJX4aJKLlP1k5dfi8+XNYu/RTnOTzWxOJgPsQqzeQEcWv9whGuZE4U+WLeQ1 +KCLRkhHlVoUg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Li Nan , Josef Bacik , Jens Axboe , Sasha Levin , linux-block@vger.kernel.org, nbd@other.debian.org Subject: [PATCH AUTOSEL 6.6 12/40] nbd: factor out a helper to get nbd_config without holding 'config_lock' Date: Tue, 28 Nov 2023 16:05:18 -0500 Message-ID: <20231128210615.875085-12-sashal@kernel.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231128210615.875085-1-sashal@kernel.org> References: <20231128210615.875085-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.3 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Li Nan [ Upstream commit 3123ac77923341774ca3ad1196ad20bb0732bf70 ] There are no functional changes, just to make code cleaner and prepare to fix null-ptr-dereference while accessing 'nbd->config'. Signed-off-by: Li Nan Reviewed-by: Josef Bacik Link: https://lore.kernel.org/r/20231116162316.1740402-3-linan666@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/nbd.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 02f844832d912..daaf8805e876c 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -395,6 +395,14 @@ static u32 req_to_nbd_cmd_type(struct request *req) } } +static struct nbd_config *nbd_get_config_unlocked(struct nbd_device *nbd) +{ + if (refcount_inc_not_zero(&nbd->config_refs)) + return nbd->config; + + return NULL; +} + static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req) { struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req); @@ -409,13 +417,13 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req) return BLK_EH_DONE; } - if (!refcount_inc_not_zero(&nbd->config_refs)) { + config = nbd_get_config_unlocked(nbd); + if (!config) { cmd->status = BLK_STS_TIMEOUT; __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags); mutex_unlock(&cmd->lock); goto done; } - config = nbd->config; if (config->num_connections > 1 || (config->num_connections == 1 && nbd->tag_set.timeout)) { @@ -977,12 +985,12 @@ static int nbd_handle_cmd(struct nbd_cmd *cmd, int index) struct nbd_sock *nsock; int ret; - if (!refcount_inc_not_zero(&nbd->config_refs)) { + config = nbd_get_config_unlocked(nbd); + if (!config) { dev_err_ratelimited(disk_to_dev(nbd->disk), "Socks array is empty\n"); return -EINVAL; } - config = nbd->config; if (index >= config->num_connections) { dev_err_ratelimited(disk_to_dev(nbd->disk), @@ -1560,6 +1568,7 @@ static int nbd_alloc_and_init_config(struct nbd_device *nbd) static int nbd_open(struct gendisk *disk, blk_mode_t mode) { struct nbd_device *nbd; + struct nbd_config *config; int ret = 0; mutex_lock(&nbd_index_mutex); @@ -1572,7 +1581,9 @@ static int nbd_open(struct gendisk *disk, blk_mode_t mode) ret = -ENXIO; goto out; } - if (!refcount_inc_not_zero(&nbd->config_refs)) { + + config = nbd_get_config_unlocked(nbd); + if (!config) { mutex_lock(&nbd->config_lock); if (refcount_inc_not_zero(&nbd->config_refs)) { mutex_unlock(&nbd->config_lock); @@ -1588,7 +1599,7 @@ static int nbd_open(struct gendisk *disk, blk_mode_t mode) mutex_unlock(&nbd->config_lock); if (max_part) set_bit(GD_NEED_PART_SCAN, &disk->state); - } else if (nbd_disconnected(nbd->config)) { + } else if (nbd_disconnected(config)) { if (max_part) set_bit(GD_NEED_PART_SCAN, &disk->state); } @@ -2205,7 +2216,8 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info) } mutex_unlock(&nbd_index_mutex); - if (!refcount_inc_not_zero(&nbd->config_refs)) { + config = nbd_get_config_unlocked(nbd); + if (!config) { dev_err(nbd_to_dev(nbd), "not configured, cannot reconfigure\n"); nbd_put(nbd); @@ -2213,7 +2225,6 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info) } mutex_lock(&nbd->config_lock); - config = nbd->config; if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) || !nbd->pid) { dev_err(nbd_to_dev(nbd), -- 2.42.0