[PATCH 29/42] docs: scsi: convert scsi_fc_transport.txt to ReST

Mauro Carvalho Chehab
2020-03-02T08:17:02Z

...fc_transport.txt => scsi_fc_transport.rst} | 236 +++++++++++-------
2 files changed, 151 insertions(+), 86 deletions(-)
rename Documentation/scsi/{scsi_fc_transport.txt => scsi_fc_transport.rst} (74%)

diff --git a/Documentation/scsi/index.rst b/Documentation/scsi/index.rst
index 8da7c27f73b7..471982ef461d 100644
--- a/Documentation/scsi/index.rst
+++ b/Documentation/scsi/index.rst
@@ -33,5 +33,6 @@ Linux SCSI Subsystem
qlogicfas
scsi-changer
scsi_eh
+ scsi_fc_transport

scsi_transport_srp/figures
diff --git a/Documentation/scsi/scsi_fc_transport.txt b/Documentation/scsi/scsi_fc_transport.rst
similarity index 74%
rename from Documentation/scsi/scsi_fc_transport.txt
rename to Documentation/scsi/scsi_fc_transport.rst
index f79282fc48d7..176c1862cb9b 100644
--- a/Documentation/scsi/scsi_fc_transport.txt
+++ b/Documentation/scsi/scsi_fc_transport.rst
@@ -1,8 +1,13 @@
- 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?)
@@ -12,25 +17,27 @@ Introduction
============
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
@@ -61,12 +68,14 @@ Overview:
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,
@@ -91,18 +100,29 @@ Device Trees and Vport Objects:
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
@@ -116,8 +136,8 @@ Device Trees and Vport Objects:
/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

@@ -184,16 +204,18 @@ Vport 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.

@@ -227,6 +249,7 @@ Vport States:
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.
@@ -251,32 +274,53 @@ Vport States:

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:
@@ -285,8 +329,8 @@ Vport States:
Link goes down Linkdown

-Transport <-> LLDD Interfaces :
--------------------------------
+Transport <-> LLDD Interfaces
+-----------------------------

Vport support by LLDD:

@@ -300,14 +344,17 @@ 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
@@ -317,6 +364,7 @@ Vport Creation:
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
@@ -329,6 +377,7 @@ Vport Creation:
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.
@@ -337,11 +386,15 @@ 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.
@@ -349,17 +402,21 @@ Vport Creation:
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,
@@ -373,14 +430,17 @@ Vport Creation:

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.
@@ -401,11 +461,12 @@ Vport Disable/Enable:

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
@@ -443,39 +504,42 @@ Transport supplied functions

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
+ ================== =========================
+ fc_vport_create create a vport
+ fc_vport_terminate detach and remove a vport
+ ================== =========================

-Details:
+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_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_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 >>

--
2.21.1