From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELuM8c95jV91of5N2bYVZI7bd1jVD/VijnlcJ8IOkOMvq1uHJMjR9Ak4oajLGexYv1LTmadI ARC-Seal: i=1; a=rsa-sha256; t=1520641163; cv=none; d=google.com; s=arc-20160816; b=nJyt65iDJMC3oB7F6MqHFjJx4UmNb/hB88Qvwu0IvFoJwQeRIO5MDhBh9JJ5FtYT7r sQtvgFcDzqQm9ghFoVoc197+D4GmQ2l7YclaDpOF4dO1Xv/JA0NOeG1mslBENMIGqTvx c/2RaygRBrOgqKlZ6dt1ejBAM+XLHjgFiQXB+Hf4m82YCthmeS40yhFl/CNtNiAPBb8R kJf5L6xdC5xYB+nZhyIeBRm5kwmG5SoCnUnYMTvaxavb9IUK50Imrar2o/o1Onda2JfW AVWYsy1tWPJEUQTK4I3fxjGPQCvyXgZjZVkSCwlLajp9umIWjjNImHNRtV3/mGOWlG79 L9lQ== 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=c+JBkeiz8qvLHR0Hllk/oA44/Ckoh9y4eHBySFFg/Ug=; b=OMzqRsk9spSY//JbohB8BuwEBTMDyoNx5OvnqSs9M3r3tFMa93gBDYYpWzzLmgoYLF bD2tAI/AXVFw+SRupiFzldypXft54zRJgBs2moe/+jogErzruD7XBXsn+6Ra6mdZiWA7 rtS2tj85SkYZaEvZ9HN0AW8W2D2w+LT3P/YQyacJUQimuiQfcG76Q7Sofbl8HRDYBX33 zJs3UPNdw97suaGGZ6RfHVju46bsexxfBSFPRBn+TmysKbXFdvgurjbgVtnKYZ2Ea/IO AEe7aLgQwzAXA5djQqp2MWnTuEQqA1d99/7fD2aavG/M4t0M1gXrG3jDJ1t5BadVnkrY KBag== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 185.236.200.248 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 185.236.200.248 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, Julian Wiedmann , "David S. Miller" Subject: [PATCH 3.18 17/21] s390/qeth: fix IPA command submission race Date: Fri, 9 Mar 2018 16:18:39 -0800 Message-Id: <20180310001802.145536649@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180310001801.045114869@linuxfoundation.org> References: <20180310001801.045114869@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?1594507828423441186?= X-GMAIL-MSGID: =?utf-8?q?1594507828423441186?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Julian Wiedmann [ Upstream commit d22ffb5a712f9211ffd104c38fc17cbfb1b5e2b0 ] If multiple IPA commands are build & sent out concurrently, fill_ipacmd_header() may assign a seqno value to a command that's different from what send_control_data() later assigns to this command's reply. This is due to other commands passing through send_control_data(), and incrementing card->seqno.ipa along the way. So one IPA command has no reply that's waiting for its seqno, while some other IPA command has multiple reply objects waiting for it. Only one of those waiting replies wins, and the other(s) times out and triggers a recovery via send_ipa_cmd(). Fix this by making sure that the same seqno value is assigned to a command and its reply object. Do so immediately before submitting the command & while holding the irq_pending "lock", to produce nicely ascending seqnos. As a side effect, *all* IPA commands now use a reply object that's waiting for its actual seqno. Previously, early IPA commands that were submitted while the card was still DOWN used the "catch-all" IDX seqno. Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/s390/net/qeth_core_main.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -2037,25 +2037,26 @@ int qeth_send_control_data(struct qeth_c } reply->callback = reply_cb; reply->param = reply_param; - if (card->state == CARD_STATE_DOWN) - reply->seqno = QETH_IDX_COMMAND_SEQNO; - else - reply->seqno = card->seqno.ipa++; + init_waitqueue_head(&reply->wait_q); - spin_lock_irqsave(&card->lock, flags); - list_add_tail(&reply->list, &card->cmd_waiter_list); - spin_unlock_irqrestore(&card->lock, flags); QETH_DBF_HEX(CTRL, 2, iob->data, QETH_DBF_CTRL_LEN); while (atomic_cmpxchg(&card->write.irq_pending, 0, 1)) ; - qeth_prepare_control_data(card, len, iob); if (IS_IPA(iob->data)) { cmd = __ipa_cmd(iob); + cmd->hdr.seqno = card->seqno.ipa++; + reply->seqno = cmd->hdr.seqno; event_timeout = QETH_IPA_TIMEOUT; } else { + reply->seqno = QETH_IDX_COMMAND_SEQNO; event_timeout = QETH_TIMEOUT; } + qeth_prepare_control_data(card, len, iob); + + spin_lock_irqsave(&card->lock, flags); + list_add_tail(&reply->list, &card->cmd_waiter_list); + spin_unlock_irqrestore(&card->lock, flags); timeout = jiffies + event_timeout; @@ -2889,7 +2890,7 @@ static void qeth_fill_ipacmd_header(stru memset(cmd, 0, sizeof(struct qeth_ipa_cmd)); cmd->hdr.command = command; cmd->hdr.initiator = IPA_CMD_INITIATOR_HOST; - cmd->hdr.seqno = card->seqno.ipa; + /* cmd->hdr.seqno is set by qeth_send_control_data() */ cmd->hdr.adapter_type = qeth_get_ipa_adp_type(card->info.link_type); cmd->hdr.rel_adapter_no = (__u8) card->info.portno; if (card->options.layer2)