- SCSI FC Tansport
- =============================================
+.. SPDX-License-Identifier: GPL-2.0
+
+================
+SCSI FC Tansport
+================
Date: 11/18/2008
-Kernel Revisions for features:
+
+Kernel Revisions for features::
+
rports : <<TBS>>
vports : 2.6.22
bsg support : 2.6.30 (?TBD?)
============
This file documents the features and components of the SCSI FC Transport.
It also provides documents the API between the transport and FC LLDDs.
-The FC transport can be found at:
+
+The FC transport can be found at::
+
drivers/scsi/scsi_transport_fc.c
include/scsi/scsi_transport_fc.h
include/scsi/scsi_netlink_fc.h
include/scsi/scsi_bsg_fc.h
-This file is found at Documentation/scsi/scsi_fc_transport.txt
+This file is found at Documentation/scsi/scsi_fc_transport.rst
FC Remote Ports (rports)
-========================================================================
+========================
<< To Be Supplied >>
FC Virtual Ports (vports)
-========================================================================
+=========================
-Overview:
--------------------------------
+Overview
+--------
New FC standards have defined mechanisms which allows for a single physical
port to appear on as multiple communication ports. Using the N_Port Id
Thus, whether a FC port is based on a physical port or on a virtual port,
each will appear as a unique scsi_host with its own target and lun space.
- Note: At this time, the transport is written to create only NPIV-based
+ .. Note::
+ At this time, the transport is written to create only NPIV-based
vports. However, consideration was given to VF-based vports and it
should be a minor change to add support if needed. The remaining
discussion will concentrate on NPIV.
- Note: World Wide Name assignment (and uniqueness guarantees) are left
+ .. Note::
+ World Wide Name assignment (and uniqueness guarantees) are left
up to an administrative entity controlling the vport. For example,
if vports are to be associated with virtual machines, a XEN mgmt
utility would be responsible for creating wwpn/wwnn's for the vport,
port's scsi_host.
Here's what to expect in the device tree :
- The typical Physical Port's Scsi_Host:
+
+ The typical Physical Port's Scsi_Host::
+
/sys/devices/.../host17/
- and it has the typical descendant tree:
+
+ and it has the typical descendant tree::
+
/sys/devices/.../host17/rport-17:0-0/target17:0:0/17:0:0:0:
- and then the vport is created on the Physical Port:
+
+ and then the vport is created on the Physical Port::
+
/sys/devices/.../host17/vport-17:0-0
- and the vport's Scsi_Host is then created:
+
+ and the vport's Scsi_Host is then created::
+
/sys/devices/.../host17/vport-17:0-0/host18
- and then the rest of the tree progresses, such as:
+
+ and then the rest of the tree progresses, such as::
+
/sys/devices/.../host17/vport-17:0-0/host18/rport-18:0-0/target18:0:0/18:0:0:0:
- Here's what to expect in the sysfs tree :
+ Here's what to expect in the sysfs tree::
+
scsi_hosts:
/sys/class/scsi_host/host17 physical port's scsi_host
/sys/class/scsi_host/host18 vport's scsi_host
/sys/class/fc_remote_ports/rport-18:0-0 rport on the vport
-Vport Attributes:
--------------------------------
+Vport Attributes
+----------------
The new fc_vport class object has the following attributes
(e.g. 0x, x, etc).
-Vport States:
--------------------------------
+Vport States
+------------
Vport instantiation consists of two parts:
+
- Creation with the kernel and LLDD. This means all transport and
driver data structures are built up, and device objects created.
This is equivalent to a driver "attach" on an adapter, which is
independent of the adapter's link state.
- Instantiation of the vport on the FC link via ELS traffic, etc.
This is equivalent to a "link up" and successful link initialization.
+
Further information can be found in the interfaces section below for
Vport Creation.
FC_VPORT_NO_FABRIC_SUPP - No Fabric Support
The vport is not operational. One of the following conditions were
encountered:
+
- The FC topology is not Point-to-Point
- The FC port is not connected to an F_Port
- The F_Port has indicated that NPIV is not supported.
The following state table indicates the different state transitions:
- State Event New State
- --------------------------------------------------------------------
- n/a Initialization Unknown
- Unknown: Link Down Linkdown
- Link Up & Loop No Fabric Support
- Link Up & no Fabric No Fabric Support
- Link Up & FLOGI response No Fabric Support
- indicates no NPIV support
- Link Up & FDISC being sent Initializing
- Disable request Disable
- Linkdown: Link Up Unknown
- Initializing: FDISC ACC Active
- FDISC LS_RJT w/ no resources No Fabric Resources
- FDISC LS_RJT w/ invalid Fabric Rejected WWN
- pname or invalid nport_id
- FDISC LS_RJT failed for Vport Failed
- other reasons
- Link Down Linkdown
- Disable request Disable
- Disable: Enable request Unknown
- Active: LOGO received from fabric Fabric Logout
- Link Down Linkdown
- Disable request Disable
- Fabric Logout: Link still up Unknown
+ +------------------+--------------------------------+---------------------+
+ | State | Event | New State |
+ +==================+================================+=====================+
+ | n/a | Initialization | Unknown |
+ +------------------+--------------------------------+---------------------+
+ | Unknown: | Link Down | Linkdown |
+ | +--------------------------------+---------------------+
+ | | Link Up & Loop | No Fabric Support |
+ | +--------------------------------+---------------------+
+ | | Link Up & no Fabric | No Fabric Support |
+ | +--------------------------------+---------------------+
+ | | Link Up & FLOGI response | No Fabric Support |
+ | | indicates no NPIV support | |
+ | +--------------------------------+---------------------+
+ | | Link Up & FDISC being sent | Initializing |
+ | +--------------------------------+---------------------+
+ | | Disable request | Disable |
+ +------------------+--------------------------------+---------------------+
+ | Linkdown: | Link Up | Unknown |
+ +------------------+--------------------------------+---------------------+
+ | Initializing: | FDISC ACC | Active |
+ | +--------------------------------+---------------------+
+ | | FDISC LS_RJT w/ no resources | No Fabric Resources |
+ | +--------------------------------+---------------------+
+ | | FDISC LS_RJT w/ invalid | Fabric Rejected WWN |
+ | | pname or invalid nport_id | |
+ | +--------------------------------+---------------------+
+ | | FDISC LS_RJT failed for | Vport Failed |
+ | | other reasons | |
+ | +--------------------------------+---------------------+
+ | | Link Down | Linkdown |
+ | +--------------------------------+---------------------+
+ | | Disable request | Disable |
+ +------------------+--------------------------------+---------------------+
+ | Disable: | Enable request | Unknown |
+ +------------------+--------------------------------+---------------------+
+ | Active: | LOGO received from fabric | Fabric Logout |
+ | +--------------------------------+---------------------+
+ | | Link Down | Linkdown |
+ | +--------------------------------+---------------------+
+ | | Disable request | Disable |
+ +------------------+--------------------------------+---------------------+
+ | Fabric Logout: | Link still up | Unknown |
+ +------------------+--------------------------------+---------------------+
+
+The following 4 error states all have the same transitions::
- The following 4 error states all have the same transitions:
No Fabric Support:
No Fabric Resources:
Fabric Rejected WWN:
Link goes down Linkdown
-Transport <-> LLDD Interfaces :
--------------------------------
+Transport <-> LLDD Interfaces
+-----------------------------
Vport support by LLDD:
Vport Creation:
- The LLDD vport_create() syntax is:
+ The LLDD vport_create() syntax is::
int vport_create(struct fc_vport *vport, bool disable)
- where:
- vport: Is the newly allocated vport object
- disable: If "true", the vport is to be created in a disabled stated.
+ where:
+
+ ======= ===========================================================
+ vport Is the newly allocated vport object
+ disable If "true", the vport is to be created in a disabled stated.
If "false", the vport is to be enabled upon creation.
+ ======= ===========================================================
When a request is made to create a new vport (via sgio/netlink, or the
vport_create fc_host attribute), the transport will validate that the LLDD
LLDD's vport_create() function with the newly allocated vport object.
As mentioned above, vport creation is divided into two parts:
+
- Creation with the kernel and LLDD. This means all transport and
driver data structures are built up, and device objects created.
This is equivalent to a driver "attach" on an adapter, which is
infrastructure exists to support NPIV, and complete the first part of
vport creation (data structure build up) before returning. We do not
hinge vport_create() on the link-side operation mainly because:
+
- The link may be down. It is not a failure if it is. It simply
means the vport is in an inoperable state until the link comes up.
This is consistent with the link bouncing post vport creation.
FC adapter. The vport_create is synonymous with driver attachment
to the adapter, which is independent of link state.
- Note: special error codes have been defined to delineate infrastructure
+ .. Note::
+
+ special error codes have been defined to delineate infrastructure
failure cases for quicker resolution.
The expected behavior for the LLDD's vport_create() function is:
+
- Validate Infrastructure:
+
- If the driver or adapter cannot support another vport, whether
due to improper firmware, (a lie about) max_npiv, or a lack of
some other resource - return VPCERR_UNSUPPORTED.
the adapter and detects an overlap - return VPCERR_BAD_WWN.
- If the driver detects the topology is loop, non-fabric, or the
FLOGI did not support NPIV - return VPCERR_NO_FABRIC_SUPP.
+
- Allocate data structures. If errors are encountered, such as out
of memory conditions, return the respective negative Exxx error code.
- If the role is FCP Initiator, the LLDD is to :
+
- Call scsi_host_alloc() to allocate a scsi_host for the vport.
- Call scsi_add_host(new_shost, &vport->dev) to start the scsi_host
and bind it as a child of the vport device.
- Initializes the fc_host attribute values.
+
- Kick of further vport state transitions based on the disable flag and
link state - and return success (zero).
LLDD Implementers Notes:
+
- It is suggested that there be a different fc_function_templates for
the physical port and the virtual port. The physical port's template
would have the vport_create, vport_delete, and vport_disable functions,
Vport Disable/Enable:
- The LLDD vport_disable() syntax is:
+ The LLDD vport_disable() syntax is::
int vport_disable(struct fc_vport *vport, bool disable)
- where:
- vport: Is vport to be enabled or disabled
- disable: If "true", the vport is to be disabled.
+ where:
+
+ ======= =======================================
+ vport Is vport to be enabled or disabled
+ disable If "true", the vport is to be disabled.
If "false", the vport is to be enabled.
+ ======= =======================================
When a request is made to change the disabled state on a vport, the
transport will validate the request against the existing vport state.
Vport Deletion:
- The LLDD vport_delete() syntax is:
+ The LLDD vport_delete() syntax is::
int vport_delete(struct fc_vport *vport)
- where:
+ where:
+
vport: Is vport to delete
When a request is made to delete a vport (via sgio/netlink, or via the
The following functions are supplied by the FC-transport for use by LLDs.
- fc_vport_create - create a vport
- fc_vport_terminate - detach and remove a vport
-
-Details:
-
-/**
- * fc_vport_create - Admin App or LLDD requests creation of a vport
- * @shost: scsi host the virtual port is connected to.
- * @ids: The world wide names, FC4 port roles, etc for
- * the virtual port.
- *
- * Notes:
- * This routine assumes no locks are held on entry.
- */
-struct fc_vport *
-fc_vport_create(struct Scsi_Host *shost, struct fc_vport_identifiers *ids)
-
-/**
- * fc_vport_terminate - Admin App or LLDD requests termination of a vport
- * @vport: fc_vport to be terminated
- *
- * Calls the LLDD vport_delete() function, then deallocates and removes
- * the vport from the shost and object tree.
- *
- * Notes:
- * This routine assumes no locks are held on entry.
- */
-int
-fc_vport_terminate(struct fc_vport *vport)
+ ================== =========================
+ fc_vport_create create a vport
+ fc_vport_terminate detach and remove a vport
+ ================== =========================
+
+Details::
+
+ /**
+ * fc_vport_create - Admin App or LLDD requests creation of a vport
+ * @shost: scsi host the virtual port is connected to.
+ * @ids: The world wide names, FC4 port roles, etc for
+ * the virtual port.
+ *
+ * Notes:
+ * This routine assumes no locks are held on entry.
+ */
+ struct fc_vport *
+ fc_vport_create(struct Scsi_Host *shost, struct fc_vport_identifiers *ids)
+
+ /**
+ * fc_vport_terminate - Admin App or LLDD requests termination of a vport
+ * @vport: fc_vport to be terminated
+ *
+ * Calls the LLDD vport_delete() function, then deallocates and removes
+ * the vport from the shost and object tree.
+ *
+ * Notes:
+ * This routine assumes no locks are held on entry.
+ */
+ int
+ fc_vport_terminate(struct fc_vport *vport)
FC BSG support (CT & ELS passthru, and more)
-========================================================================
+============================================
+
<< To Be Supplied >>
projects / users / hch / dma-mapping.git / commitdiff