netdev - Re: [PATCH] cnic: Fix ISCSI_KEVENT_IF

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Message-ID: <C27F8246C663564A84BB7AB343977242178EE780E1@IRVEXCHCCR01.corp.ad.broadcom.com>
Date:	Wed, 29 Jul 2009 00:55:26 -0700
From:	"Michael Chan" <mchan@...adcom.com>
To:	"'Mike Christie'" <michaelc@...wisc.edu>
cc:	"davem@...emloft.net" <davem@...emloft.net>,
	"James.Bottomley@...senPartnership.com" 
	<James.Bottomley@...senPartnership.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
	"open-iscsi@...glegroups.com" <open-iscsi@...glegroups.com>
Subject: Re: [PATCH] cnic: Fix ISCSI_KEVENT_IF_DOWN message handling.

Mike Christie wrote:

> Michael Chan wrote:
> > When a net device goes down or when the bnx2i driver is unloaded,
> > the code was not generating the ISCSI_KEVENT_IF_DOWN message
> > properly and this could cause the userspace driver to crash.
> >
> > This is fixed by sending the message properly in the shutdown path.
> > cnic_uio_stop() is also added to send the message when bnx2i is
> > unregistering.
> >
> > Signed-off-by: Michael Chan <mchan@...adcom.com>
> > ---
> >  drivers/net/cnic.c |   23 +++++++++++++++++++++--
> >  1 files changed, 21 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/cnic.c b/drivers/net/cnic.c
> > index 4d1515f..4869d77 100644
> > --- a/drivers/net/cnic.c
> > +++ b/drivers/net/cnic.c
> > @@ -227,7 +227,7 @@ static int cnic_send_nlmsg(struct
> cnic_local *cp, u32 type,
> >     }
> >
> >     rcu_read_lock();
> > -   ulp_ops = rcu_dereference(cp->ulp_ops[CNIC_ULP_ISCSI]);
> > +   ulp_ops = rcu_dereference(cnic_ulp_tbl[CNIC_ULP_ISCSI]);
> >     if (ulp_ops)
> >             ulp_ops->iscsi_nl_send_msg(cp->dev, msg_type, buf, len);
> >     rcu_read_unlock();
> > @@ -319,6 +319,20 @@ static int cnic_abort_prep(struct
> cnic_sock *csk)
> >     return 0;
> >  }
> >
> > +static void cnic_uio_stop(void)
> > +{
> > +   struct cnic_dev *dev;
> > +
> > +   read_lock(&cnic_dev_lock);
> > +   list_for_each_entry(dev, &cnic_dev_list, list) {
> > +           struct cnic_local *cp = dev->cnic_priv;
> > +
> > +           if (cp->cnic_uinfo)
> > +                   cnic_send_nlmsg(cp, ISCSI_KEVENT_IF_DOWN, NULL);
>
> I don't think you can call this with the cnic_dev_lock held.
> They have
> the same sleeping restrictions as a spin_lock right? If so,
> the problem
> is that iscsi_nl_send_ms calls iscsi_offload_mesg which uses GFP_NOIO
> and can sleep.
>
>
In that case, can I send in a patch to change iscsi_offload_mesg() to
use GFP_ATOMIC?

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