We recently went back to implement a board reset. When we perform the
reset, we wanted to tear down the internal data structures and rebuild
them. Unfortunately, when it came to the rport structure, things were
odd. If we deleted them, the scsi targets and sdevs would be
torn down. Not a good thing for a temporary reset. We could block the
rports, but we either maintain the internal structures to keep the
rport reference (perhaps even replicating what's in the transport),
or we have to fatten the fc transport with new search routines to find
the rport (and deal with a case of a dangling rport that the driver
forgets).
It dawned on me that we had actually reached this state incorrectly.
When the fc transport first started, we did the block/unblock first, then
added the rport interface. The purpose of block/unblock is to hide the
temporary disappearance of the rport (e.g. being deleted, then readded).
Why are we making the driver do the block/unblock ? We should be making
the transport have only an rport add/delete, and the let the transport
handle the block/unblock.
So... This patch removes the existing fc_remote_port_block/unblock
functions. It moves the block/unblock functionality into the
fc_remote_port_add/delete functions. Updates for the lpfc driver are
included. Qlogic driver updates are also enclosed, thanks to the
contributions of Andrew Vasquez. [Note: the qla2xxx changes are
relative to the scsi-misc-2.6 tree as of this morning - which does
not include the recent patches sent by Andrew]. The zfcp driver does
not use the block/unblock functions.
One last comment: The resulting behavior feels very clean. The LLDD is
concerned only with add/delete, which corresponds to the physical
disappearance. However, the fact that the scsi target and sdevs are
not immediately torn down after the LLDD calls delete causes an
interesting scenario... the midlayer can call the xxx_slave_alloc and
xxx_queuecommand functions with a sdev that is at the location the
rport used to be. The driver must validate the device exists when it
first enters these functions. In thinking about it, this has always
been the case for the LLDD and these routines. The existing drivers
already check for existence. However, this highlights that simple
validation via data structure dereferencing needs to be watched.
To deal with this, a new transport function, fc_remote_port_chkready()
was created that LLDDs should call when they first enter these two
routines. It validates the rport state, and returns a scsi result
which could be returned. In addition to solving the above, it also
creates consistent behavior from the LLDD's when the block and deletes
are occuring.
Rejections fixed up and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Ok, here's a patch to add such a common API for fc transport users.
Relevant LLD changes (lpfc and qla2xxx) also present.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This should eliminate (at least in the mid layer) to make numeric
assumptions about any of the enumeration variables. As a side effect,
it will also make all the messages consistent and line us up nicely for
the error logging strategy (if it ever shows itself again).
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
I recently tried to construct a totally generic transport class and
found there were certain features missing from the current abstract
transport class. Most notable is that you have to hang the data on the
class_device but most of the API is framed in terms of the generic
device, not the class_device.
These changes are two fold
- Provide the class_device to all of the setup and configure APIs
- Provide and extra API to take the device and the attribute class and
return the corresponding class_device
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
We have some nasty issues with 2.6.12-rc6. Any request to scan on
the lpfc or qla2xxx FC adapters will oops. What is happening is the
system is defaulting to non-transport registered targets, which
inherit the parent of the scan. On this second scan, performed by
the attribute, the parent becomes the shost instead of the rport.
The slave functions in the 2 FC adapters use starget_to_rport()
routines, which incorrectly map the shost as an rport pointer.
Additionally, this pointed out other weaknesses:
- If the target structure is torn down outside of the transport,
we have no method for it to be regenerated at the proper parent.
- We have race conditions on the target being allocated by both
the midlayer scan (parent=shost) and by the fc transport
(parent=rport).
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
