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{
    "id": 773,
    "url": "http://patchwork.ozlabs.org/api/patches/773/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/netdev/patch/20080920.225033.261544815.davem@davemloft.net/",
    "project": {
        "id": 7,
        "url": "http://patchwork.ozlabs.org/api/projects/7/?format=api",
        "name": "Linux network development",
        "link_name": "netdev",
        "list_id": "netdev.vger.kernel.org",
        "list_email": "netdev@vger.kernel.org",
        "web_url": null,
        "scm_url": null,
        "webscm_url": null,
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<20080920.225033.261544815.davem@davemloft.net>",
    "list_archive_url": null,
    "date": "2008-09-21T05:50:33",
    "name": "[take,2] pkt_sched: Fix qdisc_watchdog() vs. dev_deactivate() race",
    "commit_ref": null,
    "pull_url": null,
    "state": "rejected",
    "archived": true,
    "hash": "b3bc6f38dc4b98638201c276b35802f899c397c4",
    "submitter": {
        "id": 15,
        "url": "http://patchwork.ozlabs.org/api/people/15/?format=api",
        "name": "David Miller",
        "email": "davem@davemloft.net"
    },
    "delegate": {
        "id": 34,
        "url": "http://patchwork.ozlabs.org/api/users/34/?format=api",
        "username": "davem",
        "first_name": "David",
        "last_name": "Miller",
        "email": "davem@davemloft.net"
    },
    "mbox": "http://patchwork.ozlabs.org/project/netdev/patch/20080920.225033.261544815.davem@davemloft.net/mbox/",
    "series": [],
    "comments": "http://patchwork.ozlabs.org/api/patches/773/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/773/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<netdev-owner@vger.kernel.org>",
        "X-Original-To": "patchwork-incoming@ozlabs.org",
        "Delivered-To": "patchwork-incoming@ozlabs.org",
        "Received": [
            "from vger.kernel.org (vger.kernel.org [209.132.176.167])\n\tby ozlabs.org (Postfix) with ESMTP id 6B486DDE2A\n\tfor <patchwork-incoming@ozlabs.org>;\n\tSun, 21 Sep 2008 15:59:15 +1000 (EST)",
            "(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751007AbYIUFuq (ORCPT <rfc822;patchwork-incoming@ozlabs.org>);\n\tSun, 21 Sep 2008 01:50:46 -0400",
            "(majordomo@vger.kernel.org) by vger.kernel.org id S1751119AbYIUFuq\n\t(ORCPT <rfc822; netdev-outgoing>); Sun, 21 Sep 2008 01:50:46 -0400",
            "from 74-93-104-97-Washington.hfc.comcastbusiness.net\n\t([74.93.104.97]:39756\n\t\"EHLO sunset.davemloft.net\" rhost-flags-OK-FAIL-OK-OK)\n\tby vger.kernel.org with ESMTP id S1750997AbYIUFup (ORCPT\n\t<rfc822;netdev@vger.kernel.org>); Sun, 21 Sep 2008 01:50:45 -0400",
            "from localhost (localhost [127.0.0.1])\n\tby sunset.davemloft.net (Postfix) with ESMTP id 933A3C8C181;\n\tSat, 20 Sep 2008 22:50:33 -0700 (PDT)"
        ],
        "Date": "Sat, 20 Sep 2008 22:50:33 -0700 (PDT)",
        "Message-Id": "<20080920.225033.261544815.davem@davemloft.net>",
        "To": "jarkao2@gmail.com",
        "Cc": "herbert@gondor.apana.org.au, netdev@vger.kernel.org,\n\tkaber@trash.net",
        "Subject": "Re: [PATCH take 2] pkt_sched: Fix qdisc_watchdog() vs.\n\tdev_deactivate() race",
        "From": "David Miller <davem@davemloft.net>",
        "In-Reply-To": "<20080920.223538.130375517.davem@davemloft.net>",
        "References": "<20080920.002137.108837580.davem@davemloft.net>\n\t<20080920234843.GA2531@ami.dom.local>\n\t<20080920.223538.130375517.davem@davemloft.net>",
        "X-Mailer": "Mew version 6.1 on Emacs 22.1 / Mule 5.0 (SAKAKI)",
        "Mime-Version": "1.0",
        "Content-Type": "Text/Plain; charset=us-ascii",
        "Content-Transfer-Encoding": "7bit",
        "Sender": "netdev-owner@vger.kernel.org",
        "Precedence": "bulk",
        "List-ID": "<netdev.vger.kernel.org>",
        "X-Mailing-List": "netdev@vger.kernel.org"
    },
    "content": "From: David Miller <davem@davemloft.net>\nDate: Sat, 20 Sep 2008 22:35:38 -0700 (PDT)\n\n> Therefore it seems logical that what really needs to happen is that\n> we simply pick some new local special token value for 'ret' so that\n> we can handle that case.  \"-1\" would probably work fine.\n ...\n> I also think the qdisc_run() test needs to be there.  When the TX\n> queue fills up, we will doing tons of completely useless work going:\n\nOk, here is the kind of thing I'm suggesting in all of this.\n\nIt gets rid of bouncing unnecessarily into __qdisc_run() when\ndev_queue_xmit()'s finally selected TXQ is stopped.\n\nIt also gets rid of the dev_requeue_skb() looping case Jarek\ndiscovered.\n\n--\nTo unsubscribe from this list: send the line \"unsubscribe netdev\" in\nthe body of a message to majordomo@vger.kernel.org\nMore majordomo info at  http://vger.kernel.org/majordomo-info.html",
    "diff": "diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h\nindex b786a5b..4082f39 100644\n--- a/include/net/pkt_sched.h\n+++ b/include/net/pkt_sched.h\n@@ -90,10 +90,7 @@ extern void __qdisc_run(struct Qdisc *q);\n \n static inline void qdisc_run(struct Qdisc *q)\n {\n-\tstruct netdev_queue *txq = q->dev_queue;\n-\n-\tif (!netif_tx_queue_stopped(txq) &&\n-\t    !test_and_set_bit(__QDISC_STATE_RUNNING, &q->state))\n+\tif (!test_and_set_bit(__QDISC_STATE_RUNNING, &q->state))\n \t\t__qdisc_run(q);\n }\n \ndiff --git a/net/core/dev.c b/net/core/dev.c\nindex fdfc4b6..4654127 100644\n--- a/net/core/dev.c\n+++ b/net/core/dev.c\n@@ -1809,7 +1809,15 @@ gso:\n \t\t\trc = NET_XMIT_DROP;\n \t\t} else {\n \t\t\trc = qdisc_enqueue_root(skb, q);\n-\t\t\tqdisc_run(q);\n+\n+\t\t\ttxq = NULL;\n+\t\t\tif (rc == NET_XMIT_SUCCESS) {\n+\t\t\t\tint map = skb_get_queue_mapping(skb);\n+\t\t\t\ttxq = netdev_get_tx_queue(dev, map);\n+\t\t\t}\n+\n+\t\t\tif (!txq || !netif_tx_queue_stopped(txq))\n+\t\t\t\tqdisc_run(q);\n \t\t}\n \t\tspin_unlock(root_lock);\n \ndiff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c\nindex ec0a083..b6e6926 100644\n--- a/net/sched/sch_generic.c\n+++ b/net/sched/sch_generic.c\n@@ -117,7 +117,7 @@ static inline int handle_dev_cpu_collision(struct sk_buff *skb,\n static inline int qdisc_restart(struct Qdisc *q)\n {\n \tstruct netdev_queue *txq;\n-\tint ret = NETDEV_TX_BUSY;\n+\tint ret = -2;\n \tstruct net_device *dev;\n \tspinlock_t *root_lock;\n \tstruct sk_buff *skb;\n@@ -158,7 +158,7 @@ static inline int qdisc_restart(struct Qdisc *q)\n \t\tif (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))\n \t\t\tprintk(KERN_WARNING \"BUG %s code %d qlen %d\\n\",\n \t\t\t       dev->name, ret, q->q.qlen);\n-\n+\tcase -2:\n \t\tret = dev_requeue_skb(skb, q);\n \t\tbreak;\n \t}\n",
    "prefixes": [
        "take",
        "2"
    ]
}