[patch 0/3] zfcp FC BSG timeout fixes for 2.6.33-rc4

[Christof Schmitt <christof.schmitt@de.ibm.com>]

Here is the patch series for the FC BSG timeout problem. It is based
on the initial proposal here:
http://marc.info/?l=linux-scsi&m=126043474110957&w=2

To summarize the problem and the approach taken: The block layer runs
a timer for each FC BSG request. When the timer expires, the LLD's
bsg_timeout function is called to abort the request.  With zfcp, the
hardware does not support aborting the CT or ELS request. Instead the
hardware runs an internal timer that is setup from Linux for each CT
and BSG request. When the request times out in the block layer, the
request data structures are destroyed. When the still pending hardware
request returns, it will access already freed memory.

The solution taken here is to add a special return code to the
bsg_timeout callback to indicate that the block layer timer should be
reset. zfcp uses this to prevent the block layer timeout. To return
the FC BSG request in the time requested by the user, the hardware
timer is setup with the timeout value from the FC BSG request.

The patches apply cleanly on top of 2.6.33-rc4 and the zfcp fixes
posted yesterday.

--
Christof Schmitt