> -----Original Message-----
> From: James Bottomley [mailto:james.bottom...@hansenpartnership.com]
> Sent: Thursday, January 7, 2016 3:49 PM
> To: KY Srinivasan <k...@microsoft.com>; gre...@linuxfoundation.org; linux-
> ker...@vger.kernel.org; de...@linuxdriverproject.org; oher...@suse.com;
> jbottom...@parallels.com; h...@infradead.org; linux-s...@vger.kernel.org;
> a...@canonical.com; vkuzn...@redhat.com; jasow...@redhat.com;
> martin.peter...@oracle.com; h...@suse.de
> Cc: sta...@vger.kernel.org
> Subject: Re: [PATCH 1/1] scsi: scsi_transport_fc: Fix a bug in the error
> handling function
>
> On Thu, 2016-01-07 at 16:40 -0800, K. Y. Srinivasan wrote:
> > The macro startget_to_rport() can return NULL; handle that case
> > properly.
>
> OK, can we unwind why you think you could possibly need this? It would
> mean that fc_timed_out was called for a non-FC device, which was
> thought to be an impossibility when the fc transport class was
> designed.
As you know, on Hyper-V, FC devices are handled exactly like normal scsi
devices and the only additional information that is provided for FC devices
is the WWN for port and node. Till recently, I was not publishing the WWN in
the guest and so I was not even using the FC transport. Recently, I implemented
support for publishing the WWN in the guest and for that I am using the FC
transport
for FC hosts. When an FC LUN is dynamically removed, sometimes I see the timeout
occurring and since there is no rport associated with these devices I am
hitting the issue
this patch is addressing. I could have addressed this problem by establishing a
storvsc specific
time out function even for FC devices - the same timeout function that I
currently use for scsi
devices - storvsc_eh_timed_out(). I chose to instead fix the fc_timed_out()
function since
the code was not handling a possible condition.
Regards,
K. Y
>
> James
>
> > Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
> > Cc: <sta...@vger.kernel.org>
> > ---
> > drivers/scsi/scsi_transport_fc.c | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/scsi/scsi_transport_fc.c
> > b/drivers/scsi/scsi_transport_fc.c
> > index 24eaaf6..42a908f 100644
> > --- a/drivers/scsi/scsi_transport_fc.c
> > +++ b/drivers/scsi/scsi_transport_fc.c
> > @@ -2081,7 +2081,7 @@ fc_timed_out(struct scsi_cmnd *scmd)
> > {
> > struct fc_rport *rport = starget_to_rport(scsi_target(scmd
> > ->device));
> >
> > - if (rport->port_state == FC_PORTSTATE_BLOCKED)
> > + if ((rport == NULL) || (rport->port_state ==
> > FC_PORTSTATE_BLOCKED))
> > return BLK_EH_RESET_TIMER;
> >
> > return BLK_EH_NOT_HANDLED;
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