|| ||Robert Love <email@example.com> |
|| ||firstname.lastname@example.org |
|| ||[RFC PATCH 0/3] FC subsystem update |
|| ||Wed, 12 May 2010 13:20:03 -0700|
|| ||email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org|
|| ||Article, Thread
This series represents the continuation of the RFC archived here:
http://marc.info/?l=linux-scsi&m=126463466126962&w=2. The sysfs organization has
taken shape and object allocations make more sense than the previous RFC. The
patches have undergone my own developer testing, which has mostly focused on
NPIV port creation and deletion and some I/O.
This series creates a Fibre Channel subsystem that has an improved sysfs device
tree (the port's view of the fabric) and begins to abstract itself from SCSI.
This RFC is to solicit any feedback before I continue to refine these patches.
I've created two diagrams to help people understand the change. The first shows
the current sysfs device layout and the second shows the allocation scheme for
libfc and fcoe's primary data structures.
These patches apply to scsi-misc + the recently submitted fcoe patches, which
is the same as the fcoe-next tree on open-fcoe.org.
Overview of N_Port creation/login (for fcoe.ko):
1) First, fc.ko is installed and then scsi_transport_fcp.ko is installed.
scsi_transport_fcp.ko registers itself (SCSI initiator) as a FC4 with
2) When a fcoe port is "created" from
'echo ethX > /sys/module/fcoe/parameters/create' a fcport is allocated and
added to sysfs. All of the port's physical properties are added as
3) At this point libfc/libfcoe/fcoe needs an lport and an fcoe_port. The lport
and fcoe_ports are private data of a fcvport so a fcvport is allocated,
but not added to sysfs.
4) libfcoe.ko discovers FCFs and allocates/adds them as fcfabrics to sysfs
as they are discovered.
[ I think that we may want to revisit the idea of having a fcfport between
the fcport and fcfabric. Right now I'm creating a fcfabric for each FCF
that is discovered at the FIP phase, but that doesn't make much sense
since multiple FCFs on the same fabric can be discovered. Adding a fcfport
for each FCF discovered might be more correct. ]
5) libfc.ko will FLOGI into the fabric and upon the FLOGI ACC the fcvport
will be added to sysfs.
5.1) The FC layer will call fc4_init_add in the fc4_template. If SCSI
is the FC4, fcp_init_add (scsi_transport_fcp) will be called. This
routine calls scsi_host_alloc/scsi_add_host. There is also a callback
down to the LLD so that it can setup any SCSI-FCP private data.
[ I'm not sure how non-FCoE HBAs will do this. I imagine they will just
create all three sysfs devices (fcport, fcfabric and fcvport) on the
FLOGI ACC since they do not rely on a discovery protocol. ]
6) libfc will start discovery and as remote ports are discovered libfc will
notify FC to create and add fcrports to sysfs.
6.1) When the fcrports are created the FC layer will call fc4_targ_add in
the fc4_template. If SCSI is the FC4, fcp_targ_add (scsi_transport_fcp)
will be called. This routine will allocate a fcptarg device, add it to
sysfs and notify SCSI to scan it.
The current series shortcomings are:
1) The FC4 interface needs work to become more FC4 agnostic.
(end of include/fc/fc.h)
2) Point-to-Point mode needs to be addressed
3) BSG needs to be tested and STGT should become another FC4 that is
registered with FC. Since libfc/fcoe doesn't plug into STGT yet this
will be a challenge.
4) user space updates - For the fcoe-utils package, libhbalinux (user
space HBA API library) needs to be updated to read the new layout before
heavy testing of the new layout can be done.
5) Miscellaneous problems like error handling, fcfabric deletion cleaning
up vports, using attribute containers / scsi transport style for
SCSI-FCP devices, warnings, etc...
6) FCoE attributes...
I would love to collaborate with someone who maintains a HBA that supports
native FC since I'm not aware of the specific needs of traditional HBAs.
I would hope that this new layout could be added to the kernel (when
ready) and the existing FC Transport deprecated as I'm not sure how to get
all HBA maintainers to switch their drivers at the same time. I think that
only adding FCoE attributes to this layout would be an incentive to get LLDs
I've tried to keep this covermail brief, so there are plenty of details
left out. Please ask if you have a question.
Robert Love (3):
libfc, libfcoe, fcoe: Make use of FC subsystem
scsi_transport_fcp: Create FC/SCSI interaction layer
fc: Create FC sybsystem
drivers/Kconfig | 2
drivers/Makefile | 1
drivers/fc/Kconfig | 8
drivers/fc/Makefile | 7
drivers/fc/fcfabric.c | 425 ++++++++++
drivers/fc/fcport.c | 205 +++++
drivers/fc/fcrport.c | 1034 ++++++++++++++++++++++++
drivers/fc/fcsysfs.c | 180 ++++
drivers/fc/fcsysfs.h | 76 ++
drivers/fc/fcvport.c | 714 +++++++++++++++++
drivers/scsi/Kconfig | 11
drivers/scsi/Makefile | 1
drivers/scsi/fcoe/fcoe.c | 619 ++++++++------
drivers/scsi/fcoe/libfcoe.c | 167 +++-
drivers/scsi/libfc/fc_disc.c | 4
drivers/scsi/libfc/fc_exch.c | 2
drivers/scsi/libfc/fc_fcp.c | 130 +--
drivers/scsi/libfc/fc_libfc.h | 28 -
drivers/scsi/libfc/fc_lport.c | 195 ++---
drivers/scsi/libfc/fc_npiv.c | 44 -
drivers/scsi/libfc/fc_rport.c | 15
drivers/scsi/scsi_transport_fcp.c | 1598 +++++++++++++++++++++++++++++++++++++
include/fc/fc.h | 843 ++++++++++++++++++++
include/scsi/fc_encode.h | 34 -
include/scsi/libfc.h | 119 +--
include/scsi/libfcoe.h | 17
include/scsi/scsi_transport_fcp.h | 325 ++++++++
27 files changed, 6241 insertions(+), 563 deletions(-)
create mode 100644 drivers/fc/Kconfig
create mode 100644 drivers/fc/Makefile
create mode 100644 drivers/fc/fcfabric.c
create mode 100644 drivers/fc/fcport.c
create mode 100644 drivers/fc/fcrport.c
create mode 100644 drivers/fc/fcsysfs.c
create mode 100644 drivers/fc/fcsysfs.h
create mode 100644 drivers/fc/fcvport.c
create mode 100644 drivers/scsi/scsi_transport_fcp.c
create mode 100644 include/fc/fc.h
create mode 100644 include/scsi/scsi_transport_fcp.h
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