Method and system for supporting hardware acceleration for iSCSI read and write operations and iSCSI chimney

• US 7,921,240 B2
• Filed: 06/17/2005
• Issued: 04/05/2011
• Est. Priority Date: 03/10/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: McDaniel, Scott Sterling, Fan, Kan Frankie, Zur, Uri El
• Primary Examiner(s): Lee; Chun-Kuan
• Assistant Examiner(s): FRANKLIN, RICHARD B
• Application Number:
  US11/155,966
• Publication Number:
  US 20050281280A1
• Time in Patent Office: 2,118 Days
• Field of Search: 370/419, 709/213, 709/214, 709/230, 709232-235, 709/238, 709/250, 710/1, 710/52
• US Class Current: 710/52
• 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]
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence

Abstract

Certain aspects of a method and system for supporting hardware acceleration for iSCSI read and write operations via a TCP offload engine may comprise pre-registering at least one buffer with hardware. An iSCSI command may be received from an initiator. An initiator test tag value, a data sequence value and/or a buffer offset value of an iSCSI buffer may be compared with the pre-registered buffer. Data may be fetched from the pre-registered buffer based on comparing the initiator test tag value, the data sequence value and/or the buffer offset value of the iSCSI buffer with the pre-registered buffer. The fetched data may be zero copied from the pre-registered buffer to the initiator.

Claims

1. A method for handling data by a TCP offload engine, the method comprising:

pre-registering at least one buffer with hardware;

receiving an iSCSI command from an initiator;

comparing a data sequence value of an iSCSI buffer with said pre-registered buffer;

fetching data from said pre-registered buffer based on said comparing; and

zero copying said fetched data from said pre-registered buffer to said initiator.

2. The method according to claim 1, comprising communicating a request to transmit (R2T) signal transmitted to said initiator.

3. The method according to claim 1, comprising receiving a transmitted data out signal.

4. The method according to claim 1, comprising receiving a retransmitted TCP sequence retransmitted by said initiator in response to receiving a first frame of said zero copied fetched data in an iSCSI protocol data unit.

5. The method according to claim 4, comprising stripping a header from said iSCSI protocol data unit and placing said zero copied fetched data in said iSCSI buffer.

6. The method according to claim 4, comprising allocating said iSCSI buffer for a next frame of said zero copied fetched data in said iSCSI protocol data unit.

7. The method according to claim 1, comprising placing said zero copied fetched data into said pre-registered buffer.

8. The method according to claim 1, comprising generating an out of order message, if frames of said zero copied fetched data are not in order.

9. The method according to claim 1, comprising communicating a SCSI status signal to said initiator, if frames of said zero copied fetched data are in order.

10. The method according to claim 1, comprising verifying said zero copied fetched data.

11. The method according to claim 1, comprising comparing one or both of:

an initiator test tag value associated with said initiator and/or a buffer offset value of said iSCSI buffer with said pre-registered buffer.

12. The method according to claim 11, wherein said comparing one or both of said initiator test tag value associated with said initiator and/or said buffer offset value of said iSCSI buffer with said pre-registered buffer and comparing said data sequence value of said iSCSI buffer with said pre-registered buffer, comprises comparing each of said initiator test tag value associated with said initiator, said data sequence value and said buffer offset value of said iSCSI buffer with said pre-registered buffer.

13. A system for handling data by a TCP offload engine, the system comprising:

a target that is operable to pre-register at least one buffer with hardware;

said target is operable to receive an iSCSI command from an initiator;

said hardware is operable to compare a data sequence value of an iSCSI buffer with said pre-registered buffer;

said hardware is operable to fetch data from said pre-registered buffer based on said comparison; and

said hardware is operable to zero copy said fetched data from said pre-registered buffer to said initiator.

14. The system according to claim 13, wherein said target is operable to communicate a request to transmit (R2T) signal transmitted to said initiator.

15. The system according to claim 13 wherein said target is operable to receive a transmitted data out signal.

16. The system according to claim 13, wherein said target is operable to receive a retransmitted TCP sequence retransmitted by said initiator in response to receiving a first frame of said zero copied fetched data in an iSCSI protocol data unit.

17. The system according to claim 16, wherein said hardware is operable to strip a header from said iSCSI protocol data unit and places said zero copied fetched data in said iSCSI buffer.

18. The system according to claim 16, wherein said hardware is operable to allocate said iSCSI buffer for a next frame of said zero copied fetched data in said iSCSI protocol data unit.

19. The system according to claim 13, wherein said hardware is operable to place said zero copied fetched data into said pre-registered buffer.

20. The system according to claim 13, wherein said hardware is operable to generate an out of order message, if frames of said zero copied fetched data are not in order.

21. The system according to claim 13, wherein said hardware is operable to communicate a SCSI status signal to said initiator, if frames of said zero copied fetched data are in order.

22. The system according to claim 13, wherein said hardware is operable to verify said zero copied fetched data.

23. The system according to claim 13, wherein said hardware is operable to compare one or both of:

an initiator test tag value associated with said initiator and/or a buffer offset value of said iSCSI buffer with said pre-registered buffer.

24. The system according to claim 23, wherein said hardware is operable to compare each of said initiator test tag value associated with said initiator, said data sequence value and said buffer offset value of said iSCSI buffer with said pre-registered buffer.