From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+aV+3INT8jg3iNEbYSqOaIDqRSy1Cq5joQtuxXMaQKmV7WxkU+7ReUqAXTc0JEIIlx/ISn ARC-Seal: i=1; a=rsa-sha256; t=1523399432; cv=none; d=google.com; s=arc-20160816; b=f06KrzGKbSnDxhcKNNc/fua7EMxniSvsxCWG1z2JFPOVsNjDhelDq5zDpv3lkKJ97K wNk7zhNFlQW6WLSciFUHoOktLintpoaP3KOjCMQvuzUI9RQfpgGXz8tj1lZQl60N0Fff /3iOLb3Sae3y8+sk1AoDKuhiSZgSo7Y4k5+l+DxI0i0YUzrbKMC+6s68ujfqYW4EDqr/ X1nkkWCqc8bhpYRVdDYSGWkxBI9eb/5PqN9gxciSmDckBgX7rYAOCiZ3c6Qftaa3BeLC OxdHaYqpkDmnVFcYGSq6p1+FMN4PdilFk462NhAPkMb/CE9o3KQ7cUUvRKJP5MU8hpmG BTlA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=iAS4UHqg9i1jEDw3U1g7IFlexnpMJvfRnVeHtPZBYQ4=; b=XwQWcXl1vA+6SSjZNNf/ZBtpkCdGZcF1z083cc1Im3XqJj857nxCEoGiyH4ykF+0Sj JIjsmoSfZhiOXd8wVpi92JCbabwMUsDXxW1WE13dM4gPQM6TricO4JoVXmP6kUd2m+rd BpQAligyQemSOCiUssALOQLRJXAV96W0/GBpH0ciV7iiV0XwCBbvElRqojLYtX/ZZpg3 QpSsz3H2DiNgBtN7vXexQhNbtpry9UDsE5s56uS2aI6jt3s2jflbSPydtJO+WrDrCL2S ezhonuRujkjJEWt9gElnRoBOF2A0DxecbxSdDSaq9M7nBiIGJHpAMbszN9eFgrO6xoy1 GDVQ== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Christie , Nicholas Bellinger , Sasha Levin Subject: [PATCH 4.15 105/168] tcmu: release blocks for partially setup cmds Date: Wed, 11 Apr 2018 00:24:07 +0200 Message-Id: <20180410212804.710990639@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180410212800.144079021@linuxfoundation.org> References: <20180410212800.144079021@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597400083377091029?= X-GMAIL-MSGID: =?utf-8?q?1597400083377091029?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Christie [ Upstream commit 810b8153c4243d2012a6ec002ddd3bbc9a9ae8c2 ] If we cannot setup a cmd because we run out of ring space or global pages release the blocks before sleeping. This prevents a deadlock where dev0 has waiting_blocks set and needs N blocks, but dev1 to devX have each allocated N / X blocks and also hit the global block limit so they went to sleep. find_free_blocks is not able to take the sleeping dev's blocks becaause their waiting_blocks is set and even if it was not the block returned by find_last_bit could equal dbi_max. The latter will probably never happen because DATA_BLOCK_BITS is so high but in the next patches DATA_BLOCK_BITS and TCMU_GLOBAL_MAX_BLOCKS will be settable so it might be lower and could happen. Signed-off-by: Mike Christie Signed-off-by: Nicholas Bellinger Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/target/target_core_user.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -805,6 +805,13 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcm int ret; DEFINE_WAIT(__wait); + /* + * Don't leave commands partially setup because the unmap + * thread might need the blocks to make forward progress. + */ + tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cur); + tcmu_cmd_reset_dbi_cur(tcmu_cmd); + prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE); pr_debug("sleeping for ring space\n");