SCSITask.h |
Includes: |
SCSITask typedefs and constants used inside the kernel and user space.
Note that the SCSITaskIdentifier is an opaque object and that directly casting the SCSITaskIdentifier to any other type is discouraged. The SCSITask implementation changes when necessary to accomodate architectural changes, performance improvements, and bug fixes.
Device and protocol layer drivers that need to access information contained in a SCSITask should use the appropriate accessor methods in IOSCSIPrimaryCommandsDevice.h or IOSCSIProtocolServices.h
64-bit number to represent a SCSI Device.
64-bit number to represent a SCSI Initiator Device.
64-bit number to represent a logical unit.
Attributes for task service response.
64-bit number to represent a unique task identifier.
64-bit number to represent a SCSI Target Device.
Attributes for task delivery.
Attributes for task state.
Attributes for task status.
SCSIDeviceIdentifier |
64-bit number to represent a SCSI Device.
typedef UInt64 SCSIDeviceIdentifier;
If the identifier can either be that of an initiator or a target, SCSIDeviceIdentifier should be used.
SCSIInitiatorIdentifier |
64-bit number to represent a SCSI Initiator Device.
typedef SCSIDeviceIdentifier SCSIInitiatorIdentifier;
If the identifier is for an initiator only and not a target, then SCSIInitiatorIdentifier should be used.
SCSILogicalUnitNumber |
64-bit number to represent a logical unit.
typedef UInt64 SCSILogicalUnitNumber;
64-bit number to represent a logical unit.
SCSIServiceResponse |
Attributes for task service response.
typedef enum SCSIServiceResponse { kSCSIServiceResponse_Request_In_Process = 0, kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE = 1, kSCSIServiceResponse_TASK_COMPLETE = 2, kSCSIServiceResponse_LINK_COMMAND_COMPLETE = 3, kSCSIServiceResponse_FUNCTION_COMPLETE = 4, kSCSIServiceResponse_FUNCTION_REJECTED = 5 } SCSIServiceResponse;
kSCSIServiceResponse_Request_In_Process
Not defined in SAM specification, but is a service response used for asynchronous commands that are not yet completed.
kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE
The service request failed because of a delivery or target failure.
kSCSIServiceResponse_TASK_COMPLETE
The task completed.
kSCSIServiceResponse_LINK_COMMAND_COMPLETE
The linked command completed.
kSCSIServiceResponse_FUNCTION_COMPLETE
The task management function completed.
kSCSIServiceResponse_FUNCTION_REJECTED
The task management function was rejected.
The Service Response represents the execution status of a service request made to a Protocol Services Driver. The Service Response can only be modified by the SCSI Protocol Layer. The SCSI Application Layer can only read the state.
SCSITaggedTaskIdentifier |
64-bit number to represent a unique task identifier.
typedef UInt64 SCSITaggedTaskIdentifier;
The Tagged Task Identifier is used when a Task has a Task Attribute other than SIMPLE. The SCSI Application Layer client that controls the Logical Unit for which a Task is intended is required to guarantee that the Task Tag Identifier is unique. Zero cannot be used a a Tag value as this is used to when a Tagged Task Identifier value is needed for a Task with a SIMPLE attribute.
SCSITargetIdentifier |
64-bit number to represent a SCSI Target Device.
typedef SCSIDeviceIdentifier SCSITargetIdentifier;
If the identifier is for a target only and not an initiator, then SCSITargetIdentifier should be used.
SCSITaskAttribute |
Attributes for task delivery.
typedef enum SCSITaskAttribute { kSCSITask_SIMPLE = 0, kSCSITask_ORDERED = 1, kSCSITask_HEAD_OF_QUEUE = 2, kSCSITask_ACA = 3 } SCSITaskAttribute;
kSCSITask_SIMPLE
The task has a simple attribute.
kSCSITask_ORDERED
The task has an ordered attribute.
kSCSITask_HEAD_OF_QUEUE
The task has a head-of-queue attribute.
kSCSITask_ACA
The task has an auto-contingent-allegiance attribute.
The Task Attribute defines how this task should be managed when determing order for queueing and submission to the appropriate device server. The Task Attribute is set by the SCSI Application Layer and cannot be modified by the SCSI Protocol Layer.
SCSITaskCompletion |
typedef void ( *SCSITaskCompletion )( SCSITaskIdentifier completedTask );
This is the typedef for completion routines that work with SCSITaskIdentifiers.
SCSITaskIdentifier |
typedef OSObject * SCSITaskIdentifier;
This is an opaque object that represents a task. This is used so that drivers for both the SCSI Protocol Layer and the SCSI Application Layer cannot modify the SCSITask object directly but must instead use the inherited methods to do so. This allows the implementation of SCSITask to change without directly impacting device and protocol layer drivers. In addition, it prevents changing of properties that are not allowed to be changed by a given layer.
SCSITaskMode |
typedef enum SCSITaskMode { kSCSITaskMode_CommandExecution = 1, kSCSITaskMode_Autosense = 2 } SCSITaskMode;
The SCSI Task mode is used by the SCSI Protocol Layer to indicate what mode the task is executing.
SCSITaskState |
Attributes for task state.
typedef enum SCSITaskState { kSCSITaskState_NEW_TASK = 0, kSCSITaskState_ENABLED = 1, kSCSITaskState_BLOCKED = 2, kSCSITaskState_DORMANT = 3, kSCSITaskState_ENDED = 4 } SCSITaskState;
kSCSITaskState_NEW_TASK
The task state is new task.
kSCSITaskState_ENABLED
The task is enabled and queued.
kSCSITaskState_BLOCKED
The task is blocked.
kSCSITaskState_DORMANT
The task is dormant.
kSCSITaskState_ENDED
The task is complete.
The Task State represents the current state of the task. The state is set to NEW_TASK when the task is created. The SCSI Protocol Layer will then adjust the state as the task is queued and during execution. The SCSI Application Layer can examine the state to monitor the progress of a task. The Task State can only be modified by the SCSI Protocol Layer. The SCSI Application Layer can only read the state.
SCSITaskStatus |
Attributes for task status.
typedef enum SCSITaskStatus { kSCSITaskStatus_GOOD = 0x00, kSCSITaskStatus_CHECK_CONDITION = 0x02, kSCSITaskStatus_CONDITION_MET = 0x04, kSCSITaskStatus_BUSY = 0x08, kSCSITaskStatus_INTERMEDIATE = 0x10, kSCSITaskStatus_INTERMEDIATE_CONDITION_MET = 0x14, kSCSITaskStatus_RESERVATION_CONFLICT = 0x18, kSCSITaskStatus_TASK_SET_FULL = 0x28, kSCSITaskStatus_ACA_ACTIVE = 0x30, kSCSITaskStatus_TaskTimeoutOccurred = 0x01, kSCSITaskStatus_ProtocolTimeoutOccurred = 0x02, kSCSITaskStatus_DeviceNotResponding = 0x03, kSCSITaskStatus_DeviceNotPresent = 0x04, kSCSITaskStatus_DeliveryFailure = 0x05, kSCSITaskStatus_No_Status = 0xFF } SCSITaskStatus;
kSCSITaskStatus_GOOD
The task completed with a status of GOOD.
kSCSITaskStatus_CHECK_CONDITION
The task completed with a status of CHECK_CONDITION. Additional information about the condition should be available in the sense data.
kSCSITaskStatus_CONDITION_MET
The task completed with a status of CONDITION_MET.
kSCSITaskStatus_BUSY
The task completed with a status of BUSY. The device server might need time to process a request and a delay may be required.
kSCSITaskStatus_INTERMEDIATE
The task completed with a status of INTERMEDIATE.
kSCSITaskStatus_INTERMEDIATE_CONDITION_MET
The task completed with a status of INTERMEDIATE_CONDITION_MET.
kSCSITaskStatus_RESERVATION_CONFLICT
The task completed with a status of RESERVATION_CONFLICT.
kSCSITaskStatus_TASK_SET_FULL
The task completed with a status of TASK_SET_FULL. The device server may need to complete a task before the initiator sends another.
kSCSITaskStatus_ACA_ACTIVE
The task completed with a status of ACA_ACTIVE. The device server may need the initiator to clear the Auto-Contingent Allegiance condition before it will respond to new commands.
kSCSITaskStatus_TaskTimeoutOccurred
If a task is aborted by the SCSI Protocol Layer due to it exceeding the timeout value specified by the task, the task status shall be set to kSCSITaskStatus_TaskTimeoutOccurred.
kSCSITaskStatus_ProtocolTimeoutOccurred
If a task is aborted by the SCSI Protocol Layer due to it exceeding a timeout value specified by the support for the protocol or a related specification, the task status shall be set to kSCSITaskStatus_ProtocolTimeoutOccurred.
kSCSITaskStatus_DeviceNotResponding
If a task is unable to be delivered due to a failure of the device not accepting the task or the device acknowledging the attempt to send it the device the task status shall be set to kSCSITaskStatus_DeviceNotResponding. This will allow the SCSI Application driver to perform the necessary steps to try to recover the device. This shall only be reported after the SCSI Protocol Layer driver has attempted all protocol specific attempts to recover the device.
kSCSITaskStatus_DeviceNotPresent
If the task is unable to be delivered because the device has been detached, the task status shall be set to kSCSITaskStatus_DeviceNotPresent. This will allow the SCSI Application Layer to halt the sending of tasks to the device and, if supported, perform any device failover or system cleanup.
kSCSITaskStatus_DeliveryFailure
If the task is unable to be delivered to the device due to a failure in the SCSI Protocol Layer, such as a bus reset or communications error, but the device is is known to be functioning properly, the task status shall be set to kSCSITaskStatus_DeliveryFailure. This can also be reported if the task could not be delivered due to a protocol error that has since been corrected.
kSCSITaskStatus_No_Status
This status is not defined by the SCSI specifications, but is here to provide a status that can be returned in cases where there is not status available from the device or protocol, for example, when the service response is neither TASK_COMPLETED nor LINK_COMMAND_COMPLETE or when the service response is SERVICE_DELIVERY_OR_TARGET_FAILURE and the reason for failure could not be determined.
The Task Status represents the completion status of the task which provides the SCSI Application Layer with additional information about how to procede in handling a completed task.
The SCSI Architecture Model specification only defines task status values for when a task completes with a service response of either TASK_COMPLETED or LINK_COMMAND_COMPLETE.
Since additional information will aid in error recovery when a task fails to be completed by a device due to a service response of kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE, additional values have been defined that can be returned by the SCSI Protocol Layer to inform the SCSI Application Layer of the cause of the delivery failure.
The Task Status can only be modified by the SCSI Protocol Layer. The SCSI Application Layer can only read the status
Command Descriptor Block Size |
enum { kSCSICDBSize_Maximum = 16, kSCSICDBSize_6Byte = 6, kSCSICDBSize_10Byte = 10, kSCSICDBSize_12Byte = 12, kSCSICDBSize_16Byte = 16 };
kSCSICDBSize_Maximum
This is the largest size a Command Descriptor Block can be as specified in SPC-2.
kSCSICDBSize_6Byte
Use this for a 6-byte CDB.
kSCSICDBSize_10Byte
Use this for a 10-byte CDB.
kSCSICDBSize_12Byte
Use this for a 12-byte CDB.
kSCSICDBSize_16Byte
Use this for a 16-byte CDB.
Command Descriptor Block Size constants.
Data Transfer Direction |
enum { kSCSIDataTransfer_NoDataTransfer = 0x00, kSCSIDataTransfer_FromInitiatorToTarget = 0x01, kSCSIDataTransfer_FromTargetToInitiator = 0x02 };
kSCSIDataTransfer_NoDataTransfer
Use this for tasks that transfer no data.
kSCSIDataTransfer_FromInitiatorToTarget
Use this for tasks that transfer data from the initiator to the target.
kSCSIDataTransfer_FromTargetToInitiator
Use this for tasks that transfer data from the target to the initiator.
DataTransferDirection constants.
Untagged Task Identifier |
enum { kSCSIUntaggedTaskIdentifier = 0 };
kSCSIUntaggedTaskIdentifier
This value means the task is untagged.
The Untagged Task Identifier is used to indicate no unique tag is associated with the Task.
Last Updated: 2010-07-29