Fibre channel input/output data routing system and method

• US 8,364,853 B2
• Filed: 06/01/2011
• Issued: 01/29/2013
• Est. Priority Date: 06/01/2011
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bubb, Clinton E., Casper, Daniel F., Flanagan, John R.
• Primary Examiner(s): NGUYEN, TANH Q
• Application Number:
  US13/150,539
• Publication Number:
  US 20120311198A1
• Time in Patent Office: 608 Days
• Field of Search: 718/1, 718/100
• US Class Current: 710/5
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence
• CPC Class Codes: G06F 13/382 using universal interface adapter

Abstract

A computer program product is provided for performing a method including: obtaining information relating to an I/O operation at a channel subsystem in a host computer system; generating at least one address control word (ACW) in the local channel memory specifying one or more host memory locations for transfer of data between the host and a control unit and including at least one ACW error checking field; generating an address control structure specifying a location in the local channel memory of a corresponding ACW and including at least one address control structure error checking field; receiving a data transfer request from the network interface that includes the addressing information; comparing the at least one ACW error checking field to the at least one address control structure error checking field; and, responsive to the fields matching, routing the data transfer request to the host memory location specified in the corresponding ACW.

Claims

1. A computer program product for performing an input/output (I/O) processing operation at a host computer system configured for communication with a control unit, the computer program product comprising:

a non-transitory tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;

obtaining information relating to an I/O operation at a channel subsystem in the host computer system, the channel subsystem including at least one channel having a channel processor and a local channel memory;

generating at least one address control word (ACW) configured to specify one or more host memory locations for transfer of data between the host computer system and the control unit, and storing the at least one ACW in the local channel memory, the at least one ACW including at least one ACW error checking field configured to indicate a local channel memory region to which a data transfer request is to be routed;

generating an address control structure for each data transfer specified by the I/O operation and forwarding each address control structure from the at least one channel to a network interface between the channel subsystem and at least one I/O device, each address control structure configured to specify a location in the local channel memory of a corresponding ACW, each address control structure including at least one address control structure error checking field configured to indicate a local channel memory region to which the data transfer request is to be routed;

forwarding an I/O command message to the at least one I/O device via the network interface;

responsive to the I/O command message, receiving a data transfer request from the network interface that includes the addressing information;

comparing, by a data router in the channel, the at least one ACW error checking field to the at least one address control structure error checking field; and

responsive to the at least one ACW error checking field matching the at least one address control structure error checking field, accessing the corresponding ACW by the data router and routing the data transfer request to the host memory location specified in the corresponding ACW.

2. The computer program product of claim 1, wherein the ACW error checking field and the address control structure error checking field each includes a control (CTL) field have a CTL value, the CTL value including one of a first value indicating that the data transfer request is to be routed to a first region of the local channel memory, and a second value indicating that the data transfer request is to be routed to a second region of the local channel memory, the first region being directly accessible by the network interface for local channel operations, the second region including a plurality of ACWs for use by a data router in the channel to address the host memory.

3. The computer program product of claim 2, wherein the address control structure error checking field includes an ACW Index field that specifies a location of one ACW in a list of the plurality of ACWs in the second region.

4. The computer program product of claim 3, wherein the ACW error checking field and the address control structure error checking field each includes a validation field that includes a unique value corresponding to one ACW in the list.

5. The computer program product of claim 1, wherein a selected address control structure specifies an ACW that is accessed via multiple data transfer requests, and the error checking field of the selected address control structure includes an offset field that increments for each successive data request of the multiple data request, and each ACW error checking field includes a Next Expected Offset field that is incremented by the data router by a value corresponding to a size of the data transfer request after the data transfer request has been routed.

6. The computer program product of claim 1, wherein the I/O operation is a transport mode operation, and obtaining information includes obtaining a transport command word (TCW) at the channel subsystem, the TCW including a transport command control block (TCCB) address field including an address of a TCCB, the TCCB including a plurality of device command words (DCW) that each includes an I/O command.

7. The computer program product of claim 1, wherein the plurality of ACWs includes a Transport Command ACW configured to specify an address of the TCCB in the host memory, a Transport Read ACW configured to specify an address of a location in the host memory for storage of input data received from the control unit via a data transfer request, a Transport Write ACW configured to specify an address of a location in the host memory for retrieval of output data for transmission to the control unit, and a Transport Status ACW configured to specify lying a location in the host memory for storage of an ending status sent by the control unit at a conclusion of the I/O operation.

8. The computer program product of claim 7, wherein the one or more address control structures includes at least one of a Transport Command Address Control Structure configured to specify a location within the list of ACWs of the Transport Command ACW, one or more Transport Read Address Control Structures configured to specify a location within the list of ACWs of the Transport Read ACW, one or more Transport Write Address Control Structures configured to specify location within the list of ACWs of the Transport Write ACW, and a Transport Ending Status Address Control Structure configured to specify a location within the list of ACWs of the Transport Status ACW.

9. The computer program product of claim 1, wherein the network interface is a host bus adaptor (HBA).

10. A method of performing an input/output (I/O) processing operation at a host computer system configured for communication with a control unit, the method comprising:

obtaining information relating to an I/O operation at a channel subsystem in the host computer system, the channel subsystem including at least one channel having a channel processor and a local channel memory;

generating at least one address control word (ACW) configured to specify one or more host memory locations for transfer of data between the host computer system and the control unit, and storing the at least one ACW in the local channel memory, the at least one ACW including at least one ACW error checking field configured to indicate a local channel memory region to which a data transfer request is to be routed;

generating an address control structure for each data transfer specified by the I/O operation and forwarding each address control structure from the at least one channel to a network interface between the channel subsystem and at least one I/O device, each address control structure configured to specify a location in the local channel memory of a corresponding ACW, each address control structure including at least one address control structure error checking field configured to indicate a local channel memory region to which the data transfer request is to be routed;

forwarding an I/O command message to the at least one I/O device via the network interface;

responsive to the I/O command message, receiving a data transfer request from the network interface that includes the addressing information;

comparing, by a data router in the channel, the at least one ACW error checking field to the at least one address control structure error checking field; and

responsive to the at least one ACW error checking field matching the at least one address control structure error checking field, accessing the corresponding ACW by the data router and routing the data transfer request to the host memory location specified in the corresponding ACW.

11. The method of claim 10, wherein the ACW error checking field and the address control structure error checking field each includes a control (CTL) field have a CTL value, the CTL value including one of a first value indicating that the data transfer request is to be routed to a first region of the local channel memory, and a second value indicating that the data transfer request is to be routed to a second region of the local channel memory, the first region being directly accessible by the network interface for local channel operations, the second region including a plurality of ACWs for use by a data router in the channel to address the host memory.

12. The method of claim 11, wherein the address control structure error checking field includes an ACW Index field configured to specify a location of one ACW in a list of the plurality of ACWs in the second region.

13. The method of claim 12, wherein the ACW error checking field and the address control structure error checking field each includes a validation field that includes a unique value corresponding to one ACW in the list.

14. The method of claim 10, wherein a selected address control structure is configured to specify an ACW that is accessed via multiple data transfer requests, and the error checking field of the selected address control structure includes an offset field that increments for each successive data request of the multiple data request, and each ACW error checking field includes a Next Expected Offset field that is incremented by the data router by a value corresponding to a size of the data transfer request after the data transfer request has been routed.

15. The method of claim 10, wherein the I/O operation is a transport mode operation, and obtaining information includes obtaining a transport command word (TCW) at the channel subsystem, the TCW including a transport command control block (TCCB) address field including an address of a TCCB, the TCCB including a plurality of device command words (DCW) that each includes an I/O command.

16. The method of claim 15, wherein the plurality of ACWs includes a Transport Command ACW configured to specify an address of the TCCB in the host memory, a Transport Read ACW configured to specify an address of a location in the host memory for storage of input data received from the control unit via a data transfer request, a Transport Write ACW configured to specify an address of a location in the host memory for retrieval of output data for transmission to the control unit, and a Transport Status ACW configured to specify a location in the host memory for storage of an ending status sent by the control unit at a conclusion of the I/O operation.

17. The method of claim 16, wherein the one or more address control structures includes at least one of a Transport Command Address Control Structure configured to specify a location within the list of ACWs of the Transport Command ACW, one or more Transport Read Address Control Structures configured to specify a location within the list of ACWs of the Transport Read ACW, one or more Transport Write Address Control Structures configured to specify a location within the list of ACWs of the Transport Write ACW, and a Transport Ending Status Address Control Structure configured to specify a location within the list of ACWs of the Transport Status ACW.

18. An apparatus for performing an input/output (I/O) processing operation at a host computer system configured for communication with a control unit, the host computer system including a channel subsystem, the channel subsystem configured to communicate with the control unit via a network interface, the channel subsystem configured to perform:

obtaining information relating to an I/O operation at a channel subsystem in the host computer system, the channel subsystem including at least one channel having a channel processor and a local channel memory;

generating at least one address control word (ACW) configured to specify one or more host memory locations for transfer of data between the host computer system and the control unit, and storing the at least one ACW in the local channel memory, the at least one ACW including at least one ACW error checking field configured to indicate a local channel memory region to which a data transfer request is to be routed;

generating an address control structure for each data transfer specified by the I/O operation and forwarding each address control structure from the at least one channel to a network interface between the channel subsystem and at least one I/O device, each address control structure configured to specify a location in the local channel memory of a corresponding ACW, each address control structure including at least one address control structure error checking field configured to indicate a local channel memory region to which the data transfer request is to be routed;

forwarding an I/O command message to the at least one I/O device via the network interface;

responsive to the I/O command message, receiving a data transfer request from the network interface that includes the addressing information;

comparing, by a data router in the channel, the at least one ACW error checking field to the at least one address control structure error checking field; and

responsive to the at least one ACW error checking field matching the at least one address control structure error checking field, accessing the corresponding ACW by the data router and routing the data transfer request to the host memory location specified in the corresponding ACW.

19. The apparatus of claim 18, wherein the ACW error checking field and the address control structure error checking field each includes a control (CTL) field have a CTL value, the CTL value including one of a first value indicating that the data transfer request is to be routed to a first region of the local channel memory, and a second value indicating that the data transfer request is to be routed to a second region of the local channel memory, the first region being directly accessible by the network interface for local channel operations, the second region including a plurality of ACWs for use by a data router in the channel to address the host memory.

20. The apparatus of claim 19, wherein the address control structure error checking field includes an ACW Index field configured to specify a location of one ACW in a list of the plurality of ACWs in the second region.

21. The apparatus of claim 20, wherein the ACW error checking field and the address control structure error checking field each includes a validation field that includes a unique value corresponding to one ACW in the list.

22. The apparatus of claim 18, wherein a selected address control structure is configured to specify an ACW that is accessed via multiple data transfer requests, and the error checking field of the selected address control structure includes an offset field that increments for each successive data request of the multiple data request, and each ACW error checking field includes a Next Expected Offset field that is incremented by the data router by a value corresponding to a size of the data transfer request after the data transfer request has been routed.

23. The apparatus of claim 18, wherein the I/O operation is a transport mode operation, and obtaining information includes obtaining a transport command word (TCW) at the channel subsystem, the TCW including a transport command control block (TCCB) address field including an address of a TCCB, the TCCB including a plurality of device command words (DCW) that each includes an I/O command.

24. The apparatus of claim 23, wherein the plurality of ACWs includes a Transport Command ACW configured to specify an address of the TCCB in the host memory, a Transport Read ACW configured to specify an address of a location in the host memory for storage of input data received from the control unit via a data transfer request, a Transport Write ACW configured to specify an address of a location in the host memory for retrieval of output data for transmission to the control unit, and a Transport Status ACW configured to specify a location in the host memory for storage of an ending status sent by the control unit at a conclusion of the I/O operation.

25. The apparatus of claim 24, wherein the one or more address control structures includes at least one of a Transport Command Address Control Structure configured to specify a location within the list of ACWs of the Transport Command ACW, one or more Transport Read Address Control Structures configured to specify a location within the list of ACWs of the Transport Read ACW, one or more Transport Write Address Control Structures configured to specify a location within the list of ACWs of the Transport Write ACW, and a Transport Ending Status Address Control Structure configured to specify location within the list of ACWs of the Transport Status ACW.