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[SCSI] fc_transport: fix sysfs deadlock on vport delete
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When the vport attribute "delete" is used to delete the vport, sysfs
deadlocks waiting for the write to complete, which is waiting for the
sysfs teardown to complete. Moved this effort to a work_q element.

Took the opportunity to make some other cosmetic changes:
 - removed tabs in Doc file - replaced with expanded spaces
 - minor copyright text and author text updates
 - removed a bunch of trailing whitespace

Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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James Smart authored and James Bottomley committed May 26, 2007
1 parent bee4fe8 commit 9ef3e4a
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Showing 3 changed files with 105 additions and 93 deletions.
126 changes: 63 additions & 63 deletions Documentation/scsi/scsi_fc_transport.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -119,67 +119,67 @@ Vport Attributes:

The new fc_vport class object has the following attributes

node_name: Read_Only
node_name: Read_Only
The WWNN of the vport

port_name: Read_Only
port_name: Read_Only
The WWPN of the vport

roles: Read_Only
roles: Read_Only
Indicates the FC4 roles enabled on the vport.

symbolic_name: Read_Write
symbolic_name: Read_Write
A string, appended to the driver's symbolic port name string, which
is registered with the switch to identify the vport. For example,
a hypervisor could set this string to "Xen Domain 2 VM 5 Vport 2",
and this set of identifiers can be seen on switch management screens
to identify the port.

vport_delete: Write_Only
vport_delete: Write_Only
When written with a "1", will tear down the vport.

vport_disable: Write_Only
vport_disable: Write_Only
When written with a "1", will transition the vport to a disabled.
state. The vport will still be instantiated with the Linux kernel,
but it will not be active on the FC link.
When written with a "0", will enable the vport.

vport_last_state: Read_Only
vport_last_state: Read_Only
Indicates the previous state of the vport. See the section below on
"Vport States".

vport_state: Read_Only
vport_state: Read_Only
Indicates the state of the vport. See the section below on
"Vport States".

vport_type: Read_Only
vport_type: Read_Only
Reflects the FC mechanism used to create the virtual port.
Only NPIV is supported currently.


For the fc_host class object, the following attributes are added for vports:

max_npiv_vports: Read_Only
max_npiv_vports: Read_Only
Indicates the maximum number of NPIV-based vports that the
driver/adapter can support on the fc_host.

npiv_vports_inuse: Read_Only
npiv_vports_inuse: Read_Only
Indicates how many NPIV-based vports have been instantiated on the
fc_host.

vport_create: Write_Only
vport_create: Write_Only
A "simple" create interface to instantiate a vport on an fc_host.
A "<WWPN>:<WWNN>" string is written to the attribute. The transport
then instantiates the vport object and calls the LLDD to create the
vport with the role of FCP_Initiator. Each WWN is specified as 16
hex characters and may *not* contain any prefixes (e.g. 0x, x, etc).

vport_delete: Write_Only
vport_delete: Write_Only
A "simple" delete interface to teardown a vport. A "<WWPN>:<WWNN>"
string is written to the attribute. The transport will locate the
vport on the fc_host with the same WWNs and tear it down. Each WWN
is specified as 16 hex characters and may *not* contain any prefixes
(e.g. 0x, x, etc).
string is written to the attribute. The transport will locate the
vport on the fc_host with the same WWNs and tear it down. Each WWN
is specified as 16 hex characters and may *not* contain any prefixes
(e.g. 0x, x, etc).


Vport States:
Expand All @@ -198,89 +198,89 @@ Vport States:
Once a vport has been instantiated with the kernel/LLDD, a vport state
can be reported via the sysfs attribute. The following states exist:

FC_VPORT_UNKNOWN - Unknown
FC_VPORT_UNKNOWN - Unknown
An temporary state, typically set only while the vport is being
instantiated with the kernel and LLDD.

FC_VPORT_ACTIVE - Active
FC_VPORT_ACTIVE - Active
The vport has been successfully been created on the FC link.
It is fully functional.

FC_VPORT_DISABLED - Disabled
FC_VPORT_DISABLED - Disabled
The vport instantiated, but "disabled". The vport is not instantiated
on the FC link. This is equivalent to a physical port with the
link "down".

FC_VPORT_LINKDOWN - Linkdown
FC_VPORT_LINKDOWN - Linkdown
The vport is not operational as the physical link is not operational.

FC_VPORT_INITIALIZING - Initializing
FC_VPORT_INITIALIZING - Initializing
The vport is in the process of instantiating on the FC link.
The LLDD will set this state just prior to starting the ELS traffic
to create the vport. This state will persist until the vport is
successfully created (state becomes FC_VPORT_ACTIVE) or it fails
(state is one of the values below). As this state is transitory,
it will not be preserved in the "vport_last_state".

FC_VPORT_NO_FABRIC_SUPP - No Fabric Support
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.

FC_VPORT_NO_FABRIC_RSCS - No Fabric Resources
FC_VPORT_NO_FABRIC_RSCS - No Fabric Resources
The vport is not operational. The Fabric failed FDISC with a status
indicating that it does not have sufficient resources to complete
the operation.

FC_VPORT_FABRIC_LOGOUT - Fabric Logout
FC_VPORT_FABRIC_LOGOUT - Fabric Logout
The vport is not operational. The Fabric has LOGO'd the N_Port_ID
associated with the vport.

FC_VPORT_FABRIC_REJ_WWN - Fabric Rejected WWN
FC_VPORT_FABRIC_REJ_WWN - Fabric Rejected WWN
The vport is not operational. The Fabric failed FDISC with a status
indicating that the WWN's are not valid.

FC_VPORT_FAILED - VPort Failed
FC_VPORT_FAILED - VPort Failed
The vport is not operational. This is a catchall for all other
error conditions.


The following state table indicates the different state transitions:

State Event New State
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
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:
No Fabric Support:
No Fabric Resources:
Fabric Rejected WWN:
Vport Failed:
Disable request Disable
Link goes down Linkdown
Disable request Disable
Link goes down Linkdown


Transport <-> LLDD Interfaces :
Expand All @@ -303,9 +303,9 @@ Vport Creation:
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.
If "false", the vport is to be enabled upon creation.
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
Expand Down Expand Up @@ -342,7 +342,7 @@ Vport Creation:
- 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.
some other resource - return VPCERR_UNSUPPORTED.
- If the driver validates the WWN's against those already active on
the adapter and detects an overlap - return VPCERR_BAD_WWN.
- If the driver detects the topology is loop, non-fabric, or the
Expand All @@ -351,9 +351,9 @@ Vport Creation:
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.
- 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).

Expand All @@ -376,9 +376,9 @@ Vport Disable/Enable:
int vport_disable(struct fc_vport *vport, bool disable)

where:
vport: Is vport to to be enabled or disabled
disable: If "true", the vport is to be disabled.
If "false", the vport is to be enabled.
vport: Is vport to 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.
Expand All @@ -404,7 +404,7 @@ Vport Deletion:
int vport_delete(struct fc_vport *vport)

where:
vport: Is vport to delete
vport: Is vport to delete

When a request is made to delete a vport (via sgio/netlink, or via the
fc_host or fc_vport vport_delete attributes), the transport will call
Expand Down
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