FIBRE CHANNEL INPUT/OUTPUT DATA ROUTING SYSTEM AND METHOD

• US 20120311390A1
• Filed: 06/01/2011
• Published: 12/06/2012
• Est. Priority Date: 06/01/2011
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bubb, Clinton E., Casper, Daniel F., Flanagan, John R.
• Granted Patent: US 8,583,988 B2
• Time in Patent Office: Days
• US Class Current: 714/48
• CPC Class Codes: G06F 13/387 for adaptation of different data processing systems to different peripheral devices, e.g. protocol converters for incompatible systems, open system

Abstract

A computer program product for performing input/output (I/O) processing is provided. The computer program product is configured to perform: obtaining information relating to an I/O operation at a channel subsystem; generating and storing in local channel memory at least one address control word (ACW) specifying one or more host memory locations for data transfer and including a data check word generation field and/or a data check word save field; responsive to receiving an input data transfer request including at least one data check word, storing the at least one data check word in the data check word save field and performing a check of the data to determine whether the data has been corrupted; and responsive to receiving an output data transfer, generating at least one data check word based on the data check word generation field and appending the at least one data check word to the data.

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 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, the channel subsystem in communication with a network interface configured to transmit data between the channel subsystem and the control unit during the I/O operation;

generating at least one address control word (ACW) specifying 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 of a data check word generation field and a data check word save field;

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 the network interface, each address control structure specifying a location in the local channel memory of a corresponding ACW;

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 address control structure;

responsive to the data transfer request including data to be stored in the host memory and at least one data check word, storing the at least one data check word in the data check word save field and performing a check of the data to determine whether the data has been corrupted, and routing the data to a host memory location specified by the corresponding ACW responsive to determining that the data has not been corrupted; and

responsive to the data transfer request including a request for data to be retrieved from the host memory, retrieving the data from a host memory location specified by the corresponding ACW, generating at least one data check word based on the data check word generation field, appending the at least one data check word to the data, and routing the data and the at least one data check word to the network interface.

2. The computer program product of claim 1, wherein the at least one data check word is selected from a longitudinal redundancy check word (LRC), a cyclical redundancy check word (CRC) and a Check Sum.

3. The computer program product of claim 1, wherein the data check word generation field is a Data Check Word Seed field, and generating the at least one ACW includes inserting an initial value into the Data Check Word Seed field that is used to generate a data check word corresponding to the data transfer request.

4. The computer program product of claim 3, 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.

5. The computer program product of claim 4, wherein the data transfer request is a request for information including the TCCB for transmission by the network interface to the control unit in a Transport Command Information Unit (IU), and the at least one data check word is generated using the initial value from the Data Check Word Seed field of a Transport Command ACW data length information from the TCW and the TCCB.

6. The computer program product of claim 4, wherein the data transfer request is a request for output data from the host memory location, the at least one data check word is generated using the initial value from the Data Check Word Seed field of a Transport Write Data ACW and a length of data that is received at the channel, and the at least one data check word is appended at an end of the output data that is routed to the network interface.

7. The computer program product of claim 6, wherein the host memory location is a location of a transport indirect data address (TIDA) specifying a plurality of locations of output data, and the at least one data check word is an intermediate data check word generated using length information of output data from one of the plurality of locations.

8. The computer program product of claim 4, wherein the data transfer request includes input data to be stored in the host memory from a Read Transport Data IU, storing the at least one data check word includes storing a received data check word from the Read Transport Data IU, and performing the check includes generating a data check word using the Data Check Word Seed field of a Transport Read Data ACW and a length of input data received via the data transfer request, and comparing the received data check word to the generated data check word.

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

10-17. -17. (canceled)

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, the channel subsystem in communication with a network interface configured to transmit data between the channel subsystem and the control unit during the I/O operation;

generating at least one address control word (ACW) specifying 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 of a data check word generation field and a data check word save field;

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 the network interface, each address control structure specifying a location in the local channel memory of a corresponding ACW;

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 address control structure;

responsive to the data transfer request including data to be stored in the host memory and at least one data check word, storing the at least one data check word in the data check word save field and performing a check of the data to determine whether the data has been corrupted, and routing the data to a host memory location specified by the corresponding ACW responsive to determining that the data has not been corrupted; and

responsive to the data transfer request including a request for data to be retrieved from the host memory, retrieving the data from a host memory location specified by the corresponding ACW, generating at least one data check word based on the data check word generation field, appending the at least one data check word to the data, and routing the data and the at least one data check word to the network interface.

19. The apparatus of claim 18, wherein the at least one data check word is selected from a longitudinal redundancy check word (LRC), a cyclical redundancy check word (CRC) and a Check Sum.

20. The apparatus of claim 18, wherein the data check word generation field is a Data Check Word Seed field, and generating the at least one ACW includes inserting an initial value into the Data Check Word Seed field that is used to generate a data check word corresponding to the data transfer request.

21. The apparatus of claim 20, 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.

22. The apparatus of claim 21, wherein the data transfer request is a request for information including the TCCB for transmission by the network interface to the control unit in a Transport Command Information Unit (IU), and the at least one data check word is generated using the initial value from the Data Check Word Seed field of a Transport Command ACW data length information from the TCW and the TCCB.

23. The apparatus of claim 21, wherein the data transfer request is a request for output data from the host memory location, the at least one data check word is generated using the initial value from the Data Check Word Seed field of a Transport Write Data ACW and a length of data that is received at the channel, and the at least one data check word is appended at an end of the output data that is routed to the network interface.

24. The apparatus of claim 23, wherein the host memory location is a location of a transport indirect data address (TIDA) specifying a plurality of locations of output data, and the at least one data check word is an intermediate data check word generated using length information of output data from one of the plurality of locations.

25. The apparatus of claim 21, wherein the data transfer request includes input data to be stored in the host memory from a Read Transport Data IU, storing the at least one data check word includes storing a received data check word from the Read Transport Data IU, and performing the check includes generating a data check word using the Data Check Word Seed field of a Transport Read Data ACW and a length of input data received via the data transfer request, and comparing the received data check word to the generated data check word.