From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 73209A0C41; Wed, 17 Nov 2021 17:42:53 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 0120340687; Wed, 17 Nov 2021 17:42:53 +0100 (CET) Received: from mail-ed1-f53.google.com (mail-ed1-f53.google.com [209.85.208.53]) by mails.dpdk.org (Postfix) with ESMTP id 8363F40040 for ; Wed, 17 Nov 2021 17:42:51 +0100 (CET) Received: by mail-ed1-f53.google.com with SMTP id y12so13786406eda.12 for ; Wed, 17 Nov 2021 08:42:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nfware.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=h6oZnf5A5LWZahhANzhmR3sajMgzhhltWNMBmGNiBS0=; b=W49EYGTtjdjAT414gmdG80DpL5MBv1OjxYJe8rMA9JMQDKsTaE/C8vNw9W8V9xP9Yd yzTisgVlyGOHfGo+f8zxHQKDJwxS9vOHAxeKo5x8dxEkGvh5N42X7LXQgU3cOCShnDNP zHi/VruM6WFuyeYirrR/5+TeJXr7OcFpNDSbMZEFKaVaiD3hdkASgwLkTGY5N4+0Om9f nw3F92XMDUEr/T8p4iW+N2UM06i66vOkvAlE1HxzZN1n6Q8dCJAurdg1d9gOn3FYhC9r IodUa6Av+zl4lBWzLQ7Srue911cqMteGSQP7K2w/Xaz9uzB0ha+v6qigyiK2H5PisNKl Mo8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=h6oZnf5A5LWZahhANzhmR3sajMgzhhltWNMBmGNiBS0=; b=xQNjUScxO+0Cgj0QmzDDk1PH35UXNtOMjv8MIIspexgmbyTGxuFz2thLwuMc3Aw1yI tUsvEqVvvjUWHuPRr16sD/3Zo8ep3pYTYjLgXwoJQ07ICxRXqqG+JoadGntX4OSp94g5 oVATR43XybWitm8ZNEbpr13HcJKcI2Dhv1yffipUWnXOwPsSU7hmF3pKpbQdxkVA4ZF9 mMoNosLCjlg0gNEUYiXt9a2nNEyPgY2OtPiauGgQMgsDNXWHVu76/bOu2FGgfZwGIrCA Tjiq7bZbSKNqmloLogKWv38we63nIlNs2vFmIH/RGISgRCBB0PzhjxXiA6QmJ0lOZDYK LKWA== X-Gm-Message-State: AOAM532bgt/rHHgnz7dz5p6miF36JMKxqEyo4MvMTzSfDIhLpshSCpo1 Aanoo+ECdvfhq2x+jh2BhyyXVzPpKgdFBiZbuZ3YSw== X-Google-Smtp-Source: ABdhPJzQGShf3oR6EZnMwDfC/dJUXfxFtoS9bg4tBdTF2gaepiQobnVzi9U4DCkp4H+kY6EG9h2XwiGtcMb/6Jxx+c8= X-Received: by 2002:aa7:cc82:: with SMTP id p2mr23754478edt.201.1637167371093; Wed, 17 Nov 2021 08:42:51 -0800 (PST) MIME-Version: 1.0 References: <20211008235830.127167-1-ferruh.yigit@intel.com> In-Reply-To: <20211008235830.127167-1-ferruh.yigit@intel.com> From: Igor Ryzhov Date: Wed, 17 Nov 2021 19:42:40 +0300 Message-ID: Subject: Re: [PATCH] kni: restrict bifurcated device support To: Ferruh Yigit Cc: Elad Nachman , dev@dpdk.org, stable@dpdk.org, Eric Christian , Stephen Hemminger Content-Type: multipart/alternative; boundary="00000000000097a04d05d0febbb0" X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org --00000000000097a04d05d0febbb0 Content-Type: text/plain; charset="UTF-8" Acked-by: Igor Ryzhov On Sat, Oct 9, 2021 at 2:58 AM Ferruh Yigit wrote: > To enable bifurcated device support, rtnl_lock is released before calling > userspace callbacks and asynchronous requests are enabled. > > But these changes caused more issues, like bug #809, #816. To reduce the > scope of the problems, the bifurcated device support related changes are > only enabled when it is requested explicitly with new 'enable_bifurcated' > module parameter. > And bifurcated device support is disabled by default. > > So the bifurcated device related problems are isolated and they can be > fixed without impacting all use cases. > > Bugzilla ID: 816 > Fixes: 631217c76135 ("kni: fix kernel deadlock with bifurcated device") > Cc: stable@dpdk.org > > Signed-off-by: Ferruh Yigit > --- > Cc: Igor Ryzhov > Cc: Elad Nachman > Cc: Eric Christian > Cc: Stephen Hemminger > --- > .../prog_guide/kernel_nic_interface.rst | 28 +++++++++++++ > kernel/linux/kni/kni_dev.h | 3 ++ > kernel/linux/kni/kni_misc.c | 36 ++++++++++++++++ > kernel/linux/kni/kni_net.c | 42 +++++++++++-------- > 4 files changed, 92 insertions(+), 17 deletions(-) > > diff --git a/doc/guides/prog_guide/kernel_nic_interface.rst > b/doc/guides/prog_guide/kernel_nic_interface.rst > index 1ce03ec1a374..771c7d7fdac4 100644 > --- a/doc/guides/prog_guide/kernel_nic_interface.rst > +++ b/doc/guides/prog_guide/kernel_nic_interface.rst > @@ -56,6 +56,12 @@ can be specified when the module is loaded to control > its behavior: > off Interfaces will be created with carrier state > set to off. > on Interfaces will be created with carrier state > set to on. > (charp) > + parm: enable_bifurcated: Enable request processing support > for > + bifurcated drivers, which means releasing rtnl_lock > before calling > + userspace callback and supporting async requests > (default=off): > + on Enable request processing support for > bifurcated drivers. > + (charp) > + > > Loading the ``rte_kni`` kernel module without any optional parameters is > the typical way a DPDK application gets packets into and out of the kernel > @@ -174,6 +180,28 @@ To set the default carrier state to *off*: > If the ``carrier`` parameter is not specified, the default carrier state > of KNI interfaces will be set to *off*. > > +.. _kni_bifurcated_device_support: > + > +Bifurcated Device Support > +~~~~~~~~~~~~~~~~~~~~~~~~~ > + > +User callbacks are executed while kernel module holds the ``rtnl`` lock, > this > +causes a deadlock when callbacks run control commands on another Linux > kernel > +network interface. > + > +Bifurcated devices has kernel network driver part and to prevent deadlock > for > +them ``enable_bifurcated`` is used. > + > +To enable bifurcated device support: > + > +.. code-block:: console > + > + # insmod /kernel/linux/kni/rte_kni.ko enable_bifurcated=on > + > +Enabling bifurcated device support releases ``rtnl`` lock before calling > +callback and locks it back after callback. Also enables asynchronous > request to > +support callbacks that requires rtnl lock to work (interface down). > + > KNI Creation and Deletion > ------------------------- > > diff --git a/kernel/linux/kni/kni_dev.h b/kernel/linux/kni/kni_dev.h > index c15da311ba25..e8633486eeb8 100644 > --- a/kernel/linux/kni/kni_dev.h > +++ b/kernel/linux/kni/kni_dev.h > @@ -34,6 +34,9 @@ > /* Default carrier state for created KNI network interfaces */ > extern uint32_t kni_dflt_carrier; > > +/* Request processing support for bifurcated drivers. */ > +extern uint32_t bifurcated_support; > + > /** > * A structure describing the private information for a kni device. > */ > diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c > index 2b464c438113..aae977c187a9 100644 > --- a/kernel/linux/kni/kni_misc.c > +++ b/kernel/linux/kni/kni_misc.c > @@ -41,6 +41,10 @@ static uint32_t multiple_kthread_on; > static char *carrier; > uint32_t kni_dflt_carrier; > > +/* Request processing support for bifurcated drivers. */ > +static char *enable_bifurcated; > +uint32_t bifurcated_support; > + > #define KNI_DEV_IN_USE_BIT_NUM 0 /* Bit number for device in use */ > > static int kni_net_id; > @@ -568,6 +572,22 @@ kni_parse_carrier_state(void) > return 0; > } > > +static int __init > +kni_parse_bifurcated_support(void) > +{ > + if (!enable_bifurcated) { > + bifurcated_support = 0; > + return 0; > + } > + > + if (strcmp(enable_bifurcated, "on") == 0) > + bifurcated_support = 1; > + else > + return -1; > + > + return 0; > +} > + > static int __init > kni_init(void) > { > @@ -593,6 +613,13 @@ kni_init(void) > else > pr_debug("Default carrier state set to on.\n"); > > + if (kni_parse_bifurcated_support() < 0) { > + pr_err("Invalid parameter for bifurcated support\n"); > + return -EINVAL; > + } > + if (bifurcated_support == 1) > + pr_debug("bifurcated support is enabled.\n"); > + > #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS > rc = register_pernet_subsys(&kni_net_ops); > #else > @@ -659,3 +686,12 @@ MODULE_PARM_DESC(carrier, > "\t\ton Interfaces will be created with carrier state set to on.\n" > "\t\t" > ); > + > +module_param(enable_bifurcated, charp, 0644); > +MODULE_PARM_DESC(enable_bifurcated, > +"Enable request processing support for bifurcated drivers, " > +"which means releasing rtnl_lock before calling userspace callback and " > +"supporting async requests (default=off):\n" > +"\t\ton Enable request processing support for bifurcated drivers.\n" > +"\t\t" > +); > diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c > index 611719b5ee27..29e5b9e21f9e 100644 > --- a/kernel/linux/kni/kni_net.c > +++ b/kernel/linux/kni/kni_net.c > @@ -113,12 +113,14 @@ kni_net_process_request(struct net_device *dev, > struct rte_kni_request *req) > > ASSERT_RTNL(); > > - /* If we need to wait and RTNL mutex is held > - * drop the mutex and hold reference to keep device > - */ > - if (req->async == 0) { > - dev_hold(dev); > - rtnl_unlock(); > + if (bifurcated_support) { > + /* If we need to wait and RTNL mutex is held > + * drop the mutex and hold reference to keep device > + */ > + if (req->async == 0) { > + dev_hold(dev); > + rtnl_unlock(); > + } > } > > mutex_lock(&kni->sync_lock); > @@ -132,12 +134,14 @@ kni_net_process_request(struct net_device *dev, > struct rte_kni_request *req) > goto fail; > } > > - /* No result available since request is handled > - * asynchronously. set response to success. > - */ > - if (req->async != 0) { > - req->result = 0; > - goto async; > + if (bifurcated_support) { > + /* No result available since request is handled > + * asynchronously. set response to success. > + */ > + if (req->async != 0) { > + req->result = 0; > + goto async; > + } > } > > ret_val = wait_event_interruptible_timeout(kni->wq, > @@ -160,9 +164,11 @@ kni_net_process_request(struct net_device *dev, > struct rte_kni_request *req) > > fail: > mutex_unlock(&kni->sync_lock); > - if (req->async == 0) { > - rtnl_lock(); > - dev_put(dev); > + if (bifurcated_support) { > + if (req->async == 0) { > + rtnl_lock(); > + dev_put(dev); > + } > } > return ret; > } > @@ -207,8 +213,10 @@ kni_net_release(struct net_device *dev) > /* Setting if_up to 0 means down */ > req.if_up = 0; > > - /* request async because of the deadlock problem */ > - req.async = 1; > + if (bifurcated_support) { > + /* request async because of the deadlock problem */ > + req.async = 1; > + } > > ret = kni_net_process_request(dev, &req); > > -- > 2.31.1 > > --00000000000097a04d05d0febbb0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Acked-by: Igor Ryzhov <iryzhov@nfware.com>

On Sat, Oct 9, 2021 at 2:58 AM Ferruh Yigit= <ferruh.yigit@intel.com&g= t; wrote:
To enable bifurcated device support, rt= nl_lock is released before calling
userspace callbacks and asynchronous requests are enabled.

But these changes caused more issues, like bug #809, #816. To reduce the scope of the problems, the bifurcated device support related changes are only enabled when it is requested explicitly with new 'enable_bifurcate= d'
module parameter.
And bifurcated device support is disabled by default.

So the bifurcated device related problems are isolated and they can be
fixed without impacting all use cases.

Bugzilla ID: 816
Fixes: 631217c76135 ("kni: fix kernel deadlock with bifurcated device&= quot;)
Cc: stable@dpdk.org

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
Cc: Igor Ryzhov <iryzhov@nfware.com>
Cc: Elad Nachman <= eladv6@gmail.com>
Cc: Eric Christian <erclists@gmail.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
---
=C2=A0.../prog_guide/kernel_nic_interface.rst=C2=A0 =C2=A0 =C2=A0 =C2=A0| 2= 8 +++++++++++++
=C2=A0kernel/linux/kni/kni_dev.h=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 |=C2=A0 3 ++
=C2=A0kernel/linux/kni/kni_misc.c=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0| 36 ++++++++++++++++
=C2=A0kernel/linux/kni/kni_net.c=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 | 42 +++++++++++--------
=C2=A04 files changed, 92 insertions(+), 17 deletions(-)

diff --git a/doc/guides/prog_guide/kernel_nic_interface.rst b/doc/guides/pr= og_guide/kernel_nic_interface.rst
index 1ce03ec1a374..771c7d7fdac4 100644
--- a/doc/guides/prog_guide/kernel_nic_interface.rst
+++ b/doc/guides/prog_guide/kernel_nic_interface.rst
@@ -56,6 +56,12 @@ can be specified when the module is loaded to control it= s behavior:
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0off=C2=A0 =C2=A0Interfaces will be created with carrier state set to off= .
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0on=C2=A0 =C2=A0 Interfaces will be created with carrier state set to on.=
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 (charp)
+=C2=A0 =C2=A0 parm:=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enable_bifurca= ted: Enable request processing support for
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 bifu= rcated drivers, which means releasing rtnl_lock before calling
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 user= space callback and supporting async requests (default=3Doff):
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 on= =C2=A0 =C2=A0 Enable request processing support for bifurcated drivers.
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0(charp)
+

=C2=A0Loading the ``rte_kni`` kernel module without any optional parameters= is
=C2=A0the typical way a DPDK application gets packets into and out of the k= ernel
@@ -174,6 +180,28 @@ To set the default carrier state to *off*:
=C2=A0If the ``carrier`` parameter is not specified, the default carrier st= ate
=C2=A0of KNI interfaces will be set to *off*.

+.. _kni_bifurcated_device_support:
+
+Bifurcated Device Support
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+User callbacks are executed while kernel module holds the ``rtnl`` lock, t= his
+causes a deadlock when callbacks run control commands on another Linux ker= nel
+network interface.
+
+Bifurcated devices has kernel network driver part and to prevent deadlock = for
+them ``enable_bifurcated`` is used.
+
+To enable bifurcated device support:
+
+.. code-block:: console
+
+=C2=A0 =C2=A0 # insmod <build_dir>/kernel/linux/kni/rte_kni.ko enabl= e_bifurcated=3Don
+
+Enabling bifurcated device support releases ``rtnl`` lock before calling +callback and locks it back after callback. Also enables asynchronous reque= st to
+support callbacks that requires rtnl lock to work (interface down).
+
=C2=A0KNI Creation and Deletion
=C2=A0-------------------------

diff --git a/kernel/linux/kni/kni_dev.h b/kernel/linux/kni/kni_dev.h
index c15da311ba25..e8633486eeb8 100644
--- a/kernel/linux/kni/kni_dev.h
+++ b/kernel/linux/kni/kni_dev.h
@@ -34,6 +34,9 @@
=C2=A0/* Default carrier state for created KNI network interfaces */
=C2=A0extern uint32_t kni_dflt_carrier;

+/* Request processing support for bifurcated drivers. */
+extern uint32_t bifurcated_support;
+
=C2=A0/**
=C2=A0 * A structure describing the private information for a kni device. =C2=A0 */
diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c
index 2b464c438113..aae977c187a9 100644
--- a/kernel/linux/kni/kni_misc.c
+++ b/kernel/linux/kni/kni_misc.c
@@ -41,6 +41,10 @@ static uint32_t multiple_kthread_on;
=C2=A0static char *carrier;
=C2=A0uint32_t kni_dflt_carrier;

+/* Request processing support for bifurcated drivers. */
+static char *enable_bifurcated;
+uint32_t bifurcated_support;
+
=C2=A0#define KNI_DEV_IN_USE_BIT_NUM 0 /* Bit number for device in use */
=C2=A0static int kni_net_id;
@@ -568,6 +572,22 @@ kni_parse_carrier_state(void)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 return 0;
=C2=A0}

+static int __init
+kni_parse_bifurcated_support(void)
+{
+=C2=A0 =C2=A0 =C2=A0 =C2=A0if (!enable_bifurcated) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0bifurcated_support = =3D 0;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return 0;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0}
+
+=C2=A0 =C2=A0 =C2=A0 =C2=A0if (strcmp(enable_bifurcated, "on") = =3D=3D 0)
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0bifurcated_support = =3D 1;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0else
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return -1;
+
+=C2=A0 =C2=A0 =C2=A0 =C2=A0return 0;
+}
+
=C2=A0static int __init
=C2=A0kni_init(void)
=C2=A0{
@@ -593,6 +613,13 @@ kni_init(void)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 else
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 pr_debug("Defa= ult carrier state set to on.\n");

+=C2=A0 =C2=A0 =C2=A0 =C2=A0if (kni_parse_bifurcated_support() < 0) { +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0pr_err("Invali= d parameter for bifurcated support\n");
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return -EINVAL;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0}
+=C2=A0 =C2=A0 =C2=A0 =C2=A0if (bifurcated_support =3D=3D 1)
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0pr_debug("bifu= rcated support is enabled.\n");
+
=C2=A0#ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
=C2=A0 =C2=A0 =C2=A0 =C2=A0 rc =3D register_pernet_subsys(&kni_net_ops)= ;
=C2=A0#else
@@ -659,3 +686,12 @@ MODULE_PARM_DESC(carrier,
=C2=A0"\t\ton=C2=A0 =C2=A0 Interfaces will be created with carrier sta= te set to on.\n"
=C2=A0"\t\t"
=C2=A0);
+
+module_param(enable_bifurcated, charp, 0644);
+MODULE_PARM_DESC(enable_bifurcated,
+"Enable request processing support for bifurcated drivers, "
+"which means releasing rtnl_lock before calling userspace callback an= d "
+"supporting async requests (default=3Doff):\n"
+"\t\ton=C2=A0 =C2=A0 Enable request processing support for bifurcated= drivers.\n"
+"\t\t"
+);
diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c
index 611719b5ee27..29e5b9e21f9e 100644
--- a/kernel/linux/kni/kni_net.c
+++ b/kernel/linux/kni/kni_net.c
@@ -113,12 +113,14 @@ kni_net_process_request(struct net_device *dev, struc= t rte_kni_request *req)

=C2=A0 =C2=A0 =C2=A0 =C2=A0 ASSERT_RTNL();

-=C2=A0 =C2=A0 =C2=A0 =C2=A0/* If we need to wait and RTNL mutex is held -=C2=A0 =C2=A0 =C2=A0 =C2=A0 * drop the mutex and hold reference to keep de= vice
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 */
-=C2=A0 =C2=A0 =C2=A0 =C2=A0if (req->async =3D=3D 0) {
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0dev_hold(dev);
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0rtnl_unlock();
+=C2=A0 =C2=A0 =C2=A0 =C2=A0if (bifurcated_support) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0/* If we need to wa= it and RTNL mutex is held
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 * drop the mutex a= nd hold reference to keep device
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 */
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (req->async = =3D=3D 0) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0dev_hold(dev);
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0rtnl_unlock();
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 }

=C2=A0 =C2=A0 =C2=A0 =C2=A0 mutex_lock(&kni->sync_lock);
@@ -132,12 +134,14 @@ kni_net_process_request(struct net_device *dev, struc= t rte_kni_request *req)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 goto fail;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 }

-=C2=A0 =C2=A0 =C2=A0 =C2=A0/* No result available since request is handled=
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 * asynchronously. set response to success.
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 */
-=C2=A0 =C2=A0 =C2=A0 =C2=A0if (req->async !=3D 0) {
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0req->result =3D = 0;
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0goto async;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0if (bifurcated_support) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0/* No result availa= ble since request is handled
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 * asynchronously. = set response to success.
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 */
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (req->async != =3D 0) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0req->result =3D 0;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0goto async;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 }

=C2=A0 =C2=A0 =C2=A0 =C2=A0 ret_val =3D wait_event_interruptible_timeout(kn= i->wq,
@@ -160,9 +164,11 @@ kni_net_process_request(struct net_device *dev, struct= rte_kni_request *req)

=C2=A0fail:
=C2=A0 =C2=A0 =C2=A0 =C2=A0 mutex_unlock(&kni->sync_lock);
-=C2=A0 =C2=A0 =C2=A0 =C2=A0if (req->async =3D=3D 0) {
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0rtnl_lock();
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0dev_put(dev);
+=C2=A0 =C2=A0 =C2=A0 =C2=A0if (bifurcated_support) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (req->async = =3D=3D 0) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0rtnl_lock();
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0dev_put(dev);
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 }
=C2=A0 =C2=A0 =C2=A0 =C2=A0 return ret;
=C2=A0}
@@ -207,8 +213,10 @@ kni_net_release(struct net_device *dev)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 /* Setting if_up to 0 means down */
=C2=A0 =C2=A0 =C2=A0 =C2=A0 req.if_up =3D 0;

-=C2=A0 =C2=A0 =C2=A0 =C2=A0/* request async because of the deadlock proble= m */
-=C2=A0 =C2=A0 =C2=A0 =C2=A0req.async =3D 1;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0if (bifurcated_support) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0/* request async be= cause of the deadlock problem */
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0req.async =3D 1; +=C2=A0 =C2=A0 =C2=A0 =C2=A0}

=C2=A0 =C2=A0 =C2=A0 =C2=A0 ret =3D kni_net_process_request(dev, &req);=

--
2.31.1

--00000000000097a04d05d0febbb0--