From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: Re: e1000_netpoll(): disable_irq() triggers might_sleep() on linux-next Date: Wed, 29 Oct 2014 12:40:41 -0700 Message-ID: <1414611641.2420.54.camel@jtkirshe-mobl> References: <20141029155620.GA4886@kria> <20141029180734.GQ12706@worktop.programming.kicks-ass.net> <20141029193603.GS12706@worktop.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-O+sDjg7563QFZqVfM4eI" Cc: Thomas Gleixner , Sabrina Dubroca , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Peter Zijlstra Return-path: In-Reply-To: <20141029193603.GS12706@worktop.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --=-O+sDjg7563QFZqVfM4eI Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2014-10-29 at 20:36 +0100, Peter Zijlstra wrote: > On Wed, Oct 29, 2014 at 07:33:00PM +0100, Thomas Gleixner wrote: > > Yuck. No. You are just papering over the problem. > >=20 > > What happens if you add 'threadirqs' to the kernel command line? Or if > > the interrupt line is shared with a real threaded interrupt user? > >=20 > > The proper solution is to have a poll_lock for e1000 which serializes > > the hardware interrupt against netpoll instead of using > > disable/enable_irq(). > >=20 > > In fact that's less expensive than the disable/enable_irq() dance and > > the chance of contention is pretty low. If done right it will be a > > NOOP for the CONFIG_NET_POLL_CONTROLLER=3Dn case. > >=20 >=20 > OK a little something like so then I suppose.. But I suspect most all > the network drivers will need this and maybe more, disable_irq() is a > popular little thing and we 'just' changed semantics on them. Thomas- if you are fine with Peter's patch, I can get this under testing. >=20 > --- > drivers/net/ethernet/intel/e1000/e1000.h | 2 ++ > drivers/net/ethernet/intel/e1000/e1000_main.c | 22 +++++++++++++++++----= - > kernel/irq/manage.c | 2 +- > 3 files changed, 20 insertions(+), 6 deletions(-) >=20 > diff --git a/drivers/net/ethernet/intel/e1000/e1000.h b/drivers/net/ether= net/intel/e1000/e1000.h > index 69707108d23c..3f48609f2318 100644 > --- a/drivers/net/ethernet/intel/e1000/e1000.h > +++ b/drivers/net/ethernet/intel/e1000/e1000.h > @@ -323,6 +323,8 @@ struct e1000_adapter { > struct delayed_work watchdog_task; > struct delayed_work fifo_stall_task; > struct delayed_work phy_info_task; > + > + spinlock_t irq_lock; > }; > =20 > enum e1000_state_t { > diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/= ethernet/intel/e1000/e1000_main.c > index 5f6aded512f5..d12cbffe2149 100644 > --- a/drivers/net/ethernet/intel/e1000/e1000_main.c > +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c > @@ -1310,6 +1310,7 @@ static int e1000_sw_init(struct e1000_adapter *adap= ter) > e1000_irq_disable(adapter); > =20 > spin_lock_init(&adapter->stats_lock); > + spin_lock_init(&adapter->irq_lock); > =20 > set_bit(__E1000_DOWN, &adapter->flags); > =20 > @@ -3748,10 +3749,8 @@ void e1000_update_stats(struct e1000_adapter *adap= ter) > * @irq: interrupt number > * @data: pointer to a network interface device structure > **/ > -static irqreturn_t e1000_intr(int irq, void *data) > +static irqreturn_t __e1000_intr(int irq, struct e1000_adapter *adapter) > { > - struct net_device *netdev =3D data; > - struct e1000_adapter *adapter =3D netdev_priv(netdev); > struct e1000_hw *hw =3D &adapter->hw; > u32 icr =3D er32(ICR); > =20 > @@ -3793,6 +3792,19 @@ static irqreturn_t e1000_intr(int irq, void *data) > return IRQ_HANDLED; > } > =20 > +static irqreturn_t e1000_intr(int irq, void *data) > +{ > + struct net_device *netdev =3D data; > + struct e1000_adapter *adapter =3D netdev_priv(netdev); > + irqreturn_t ret; > + > + spin_lock(&adapter->irq_lock); > + ret =3D __e1000_intr(irq, adapter); > + spin_unlock(&adapter->irq_lock); > + > + return ret; > +} > + > /** > * e1000_clean - NAPI Rx polling callback > * @adapter: board private structure > @@ -5217,9 +5229,9 @@ static void e1000_netpoll(struct net_device *netdev= ) > { > struct e1000_adapter *adapter =3D netdev_priv(netdev); > =20 > - disable_irq(adapter->pdev->irq); > + spin_lock(&adapter->irq_lock) > e1000_intr(adapter->pdev->irq, netdev); > - enable_irq(adapter->pdev->irq); > + spin_unlock(&adapter->irq_lock) > } > #endif > =20 > diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c > index 0a9104b4608b..b5a4a06bf2fd 100644 > --- a/kernel/irq/manage.c > +++ b/kernel/irq/manage.c > @@ -427,7 +427,7 @@ EXPORT_SYMBOL(disable_irq_nosync); > * to complete before returning. If you use this function while > * holding a resource the IRQ handler may need you will deadlock. > * > - * This function may be called - with care - from IRQ context. > + * This function may _NOT_ be called from IRQ context. > */ > void disable_irq(unsigned int irq) > { --=-O+sDjg7563QFZqVfM4eI Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCgAGBQJUUUK5AAoJEOVv75VaS+3OpGIP/iKB0r5+6BIyFwQIsyOty24N Iw8/XdDuTef3taRouEJy+Du1sWHieId2XmnXBzxMEPSaFKheq/05Pck4E/kxwRai HYppl7pW9khTifoqLhsrjUdOE1is5E9K9rTQivkC6UZdMBqoap2lBI8cZaQeZmNm S1SEAF2xcr6DgVH84O5H1bPHYOC/FQB17Yzt5Xg9FXKm/u90jNoylUeEIl76H83A Bf/WP/Adb41sRgAjphR9ljaTDss3Dd+ar00DDTQkCDSFPQgtLl6Cmvw9LEXhXWth ADsxHYURRxhPTj+f1stfw8oT31gicwkKPUgWeMUJmMyNe2iZH0ZJBLMllBaIuaip ap5099MC9i2LvAcqzl4e83V2sgjjMnKFueN7awfLMUrN+YpxA7CLPzZV29xW8Lii IBeCKX4Tf3PAMlIfbcH2/kZreDyVKFbdsZE/Ggo+2vNEQunbVTqsZQy2rfU1OzM7 HwRxHX6iQSYpOHZSvgfSDIRLw7hpVrbX6kjexFuD6OgN15QEMsnmD/dXDsrsPKMI +qkegPfwAXT61QQBcBKuYN+QZp9esWFLmMs3C5GnNd8lDy2SiM8SQ09WFSvHO0wV F1CNBI3PKNkFJE8dQsQjyXNmNqlj5iHpaapwNE1Eh1tABAp8YTv6YH5OOKunZXnX mSkjlsqs2xaEn1o+egtP =Yms5 -----END PGP SIGNATURE----- --=-O+sDjg7563QFZqVfM4eI--