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

• US 8,438,321 B2
• Filed: 04/05/2011
• Issued: 05/07/2013
• 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: Elzur, Uri, Fan, Kan Frankie, McDaniel, Scott Sterling
• Primary Examiner(s): Lee, Chun-Kuan
• Assistant Examiner(s): Franklin, Richard B
• Application Number:
  US13/080,285
• Publication Number:
  US 20110185089A1
• Time in Patent Office: 763 Days
• Field of Search: None
• 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, the method comprising:

a TCP offload engine receiving, from a driver, a plurality of buffers for pre-registration;

fetching, by the TCP offload engine, data from a selected one of a plurality of the pre-registered buffers based on comparing a data sequence value of an iSCSI buffer and a buffer offset value of said iSCSI buffer with said pre-registered buffers; and

zero copying, by the TCP offload engine, said fetched data from said selected pre-registered buffer to an initiator.

2. The method according to claim 1, comprising receiving an iSCSI write command from said initiator.

3. The method according to claim 2, comprising communicating a request to transmit (R2T) signal to said initiator based on said received iSCSI write command.

4. The method according to claim 3, comprising receiving a data out signal from said initiator in response to said communicated R2T signal.

5. The method according to claim 1, wherein said fetching is further based on comparing an initiator test tag value associated with said initiator with said selected pre-registered buffer.

6. The method according to claim 1, comprising retransmitting a TCP sequence to said initiator based on said zero copied said fetched data.

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

8. The method according to claim 1, wherein said zero copied said fetched data is placed in said iSCSI buffer.

9. The method according to claim 1, wherein said zero copied said fetched data is verified by said initiator.

10. A system for handling data, the system comprising:

one or more circuits that are operable to fetch data from a selected one of a plurality of pre-registered buffers based on comparing a data sequence value of an iSCSI buffer and a buffer offset value of said iSCSI buffer with said pre-registered buffers; and

said one or more circuits are operable to zero copy said fetched data from said selected pre-registered buffer to an initiator.

11. The system according to claim 10, wherein said one or more circuits are operable to receive an iSCSI write command from said initiator.

12. The system according to claim 11, wherein said one or more circuits are operable to communicate a request to transmit (R2T) signal to said initiator based on said received iSCSI write command.

13. The system according to claim 12, wherein said one or more circuits are operable to receive a data out signal from said initiator in response to said communicated R2T signal.

14. The system according to claim 10, wherein said fetch is further based on comparing an initiator test tag value associated with said initiator with said selected pre-registered buffer.

15. The system according to claim 10, wherein said one or more circuits are operable to communicate a SCSI status signal to said initiator, if frames of said zero copied said fetched data are in order.

16. The system according to claim 10, wherein said one or more circuits are operable to generate an out of order message, if frames of said zero copied said fetched data are not in order.

17. The system according to claim 10, wherein said zero copied said fetched data is placed in said iSCSI buffer.

18. The system according to claim 10, wherein said zero copied said fetched data is verified by said initiator.

19. The system according to claim 10, wherein said one or more circuits are operable to receive, from a driver, a plurality of pre-registration requests, each associated with a buffer.

20. A system for handling data, the system comprising:

processing circuitry operable to fetch data from a selected one of a plurality of pre-registered buffers based on comparing a data sequence value of an iSCSI buffer and a buffer offset value of said iSCSI buffer with said pre-registered buffers; and

processing circuitry operable to zero copy said fetched data from said selected pre-registered buffer to an initiator.

21. The system according to claim 20, further comprising processing circuitry operable to receive, from a driver, a plurality of pre-registration requests, each associated with a buffer.