netdev - Re: [PATCH] cnic: Fix ISCSI_KEVENT_IF

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Message-ID: <4A70058F.50403@cs.wisc.edu>
Date:	Wed, 29 Jul 2009 03:17:19 -0500
From:	Mike Christie <michaelc@...wisc.edu>
To:	Michael Chan <mchan@...adcom.com>
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.

Michael Chan wrote:
> 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?
> 

Yes, I guess so.
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