System and method for receiving iSCSI protocol data units

• US 7,260,631 B1
• Filed: 12/19/2003
• Issued: 08/21/2007
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: NVIDIA Corporation
• Original Assignee: NVIDIA Corporation
• Inventors: Johnson, Michael Ward, Currid, Andrew, Minami, John Shigeto, Kanuri, Mrudula
• Primary Examiner(s): Maung; Zarni
• Assistant Examiner(s): Daftuar; Saket
• Application Number:
  US10/741,681
• Time in Patent Office: 1,341 Days
• Field of Search: 709/224
• US Class Current: 709/224
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

An Internet small computer system interface (iSCSI) system, method and associated data structure are provided for receiving data in protocol data units. After a protocol data unit is received, a data list is identified that describes how the data contained in the protocol data unit is to be stored (i.e. placed, saved, etc.) in memory (i.e. application memory). Further stored is a state of the data list. To this end, the state of the data list is used in conjunction with the storage of data from a subsequent protocol data unit.

Claims

1. An Internet small computer system interface (iSCSI) method for storing a state of a data list, comprising:

receiving a protocol data unit including an iSCSI protocol data unit;

identifying a data list describing how data in the protocol data unit is to be stored in memory;

storing the data in the protocol data unit in the memory;

storing a state of the data list, where the state of the data list is used in conjunction with storage of data in a subsequent protocol data unit; and

extracting and storing information from a header portion of the protocol data unit in a control block;

wherein the information stored in the control block is utilized for identifying the data list for use in conjunction with the subsequent protocol data unit such that a plurality of related protocol data units are stored using a single data list.

2. The iSCSI method as recited in claim 1, wherein the data list includes a scatter-gather list (SGL).

3. The iSCSI method as recited in claim 1, wherein the data list includes a memory-descriptor list (MDL).

4. The iSCSI method as recited in claim 1, wherein the state is stored using a transport offload engine.

5. The iSCSI method as recited in claim 1, wherein the protocol data unit includes the header portion and a data portion.

6. The iSCSI method as recited in claim 1, wherein the information includes a tag.

7. The iSCSI method as recited in claim 1, wherein the data in at least a segment of the protocol data unit is stored in a buffer if no information is extracted or if the information extracted identifies an invalid data list.

8. The iSCSI method as recited in claim 7, wherein the buffer includes a host buffer.

9. The iSCSI method as recited in claim 7, wherein the buffer includes a transport offload engine buffer.

10. The iSCSI method as recited in claim 1, wherein a valid field is used to determine whether the data list is valid.

11. The iSCSI method as recited in claim 1, wherein the data in segments of the protocol data unit are stored using the data list until an end of the data list is detected.

12. The iSCSI method as recited in claim 11, wherein the data list is retired if the end of the data list is detected prior to the data in all of the segments of the protocol data unit being stored.

13. The iSCSI method as recited in claim 11, wherein the data in the protocol data unit is stored in a buffer if the end of the data list is detected prior to the data in all of the segments of the protocol data unit being stored.

14. The iSCSI method as recited in claim 1, wherein the data in segments of the protocol data unit are stored using the data list until an end of the protocol data unit is detected.

15. The iSCSI method as recited in claim 14, wherein the state of the data list is stored if the end of the protocol data unit is detected.

16. The iSCSI method as recited in claim 1, wherein the state indicates a location in the data list.

17. The iSCSI method as recited in claim 1, wherein if the data in a segment of the protocol data unit is received out-of-sequence, the data in the segment is stored in a buffer.

18. The iSCSI method as recited in claim 1, wherein the memory includes application memory.

19. The iSCSI method as recited in claim 1, wherein the state of the data list is updated after each use of the data list so that the subsequent protocol data unit is capable of using the data list.

20. A method for storing a state of a data list, comprising:

receiving an Internet small computer system interface (iSCSI) protocol data unit;

identifying a data list describing how data in the protocol data unit is to be stored in memory;

storing the data in the protocol data unit in the memory;

storing a state of the data list, where the state of the data list is used in conjunction with storage of data in a subsequent protocol data unit; and

extracting information from a header portion of the protocol data unit and storing the information in a control block;

wherein the information stored in the control block is utilized fox identifying the data list for use in conjunction with the subsequent protocol data unit such that a plurality of related protocol data units are stored using a single data list.

21. A transport offload engine sub-system, comprising:

a transport offload engine in communication with a processor and a network, the transport offload engine for identifying a data list describing how data in a received Internet small computer system interface (iSCSI) protocol data unit is to be stored in memory, and storing a state of the data list;

wherein the state of the data list is used in conjunction with storage of data in a subsequent protocol data unit;

wherein information is extracted from a header portion of the protocol data unit and stored in a control block;

wherein the information stored in the control block is utilized for identifying the data list for use in conjunction with the subsequent protocol data unit such that a plurality of related protocol data units are stored using a single data list.

22. A system, comprising:

a processor;

a transport offload engine in communication with the processor and a network via a bus, the transport offload engine for identifying a data list describing how data in a received Internet small computer system interface (iSCSI) protocol data unit is to be stored in memory, and storing a state of the data list;

wherein the state of the data list is used in conjunction with storage of data in a subsequent protocol data unit;

wherein information is extracted from a header portion of the protocol data unit and stored in a control block,

wherein the information stored in the control block is utilized for identifying the data list for use in conjunction with the subsequent protocol data unit such that a plurality of related protocol data units are stored using a single data list.

23. A data list data structure embodied on a computer readable medium, comprising:

a data list object for describing how data in a received Internet small computer system interface (iSCSI) protocol data unit is to be stored in memory;

wherein the data list object has stored associated therewith a state of the data list object that is used by a transport offload engine during storage of data in a subsequent protocol data unit;

wherein information is extracted from a header portion of the protocol data unit and stored in a control block;

wherein the information stored in the control block is utilized for identifying the data list object for use in conjunction with the subsequent protocol data unit such that a plurality of related protocol data units are stored using a single data list object.

24. A method for use in association with a transport offload engine, comprising:

receiving an Internet small computer system interface (iSCSI) protocol data unit, the protocol data unit including a header portion and a data portion;

extracting information from the header portion of the protocol data unit, the information including a tag;

determining whether to store data in the protocol data unit using a buffer or a data list based on the information;

if it is determined that the data in the protocol data unit is to be stored using the buffer;

storing the header portion of the protocol data unit in the buffer, and

sending a status message to a processor; and

if it is determined that the data in the protocol data unit is to be stored using the data list;

identifying the data list based on the information, the data list describing how the data in the protocol data unit is to be stored in memory,

identifying a state of the data list,

storing the data in segments of the protocol data unit in the memory based on the state,

repeating the storing until all of the data in the segments of the protocol data unit are stored, and

if all of the data in the segments of the protocol data unit are stored, storing the state of the data list;

wherein the state of the data list is used in conjunction with the storage of data in a subsequent protocol data unit;

wherein the information from the header portion of the protocol data unit is stored in a control block;

wherein the information stored in the control block is utilized for identifying the data list for use in conjunction with the subsequent protocol data unit such that a plurality of related protocol data units are stored using a single data list.

25. The method as recited in claim 24, wherein the buffer includes a host buffer.

26. The method as recited in claim 24, wherein the buffer includes a transport offload engine buffer.

27. An Internet small computer system interface (iSCSI) method, comprising:

receiving a protocol data unit including an iSCSI protocol data unit;

storing at least a portion of the protocol data unit in memory;

storing a state, where the state is used in conjunction with handling of a subsequent protocol data unit; and

extracting information from a header portion of the protocol data unit and storing the information in a control block;

wherein the information stored in the control block is utilized for identifying a data list for use in conjunction with the subsequent protocol data unit such that a plurality of related protocol data units are stored using a single data list.