Method for aborting data transfer commands
View Patent ↗A single hardware I/O control block is used to efficiently abort a target I/O command for a target I/O device, e.g., one target I/O device in a plurality of target I/O devices. The abort command is included in the same hardware I/O control block that specified the target I/O command to be aborted. Execution of both the target I/O command and the abort command returns only one hardware I/O control block pointer and generates only one interrupt to a host system when both the target I/O command and the abort command are completed. All time relationships between the execution of the abort command and execution of the original target I/O command are supported. There are no holes where the abort command is lost or where the host system is advised of target I/O command completion prematurely, or is not advised of completion at all.
1. A method comprising:
receiving, by a host adapter, a hardware I/O command block including a target I/O command for a target I/O device;
modifying said hardware I/O command block to include an abort command; and
checking a state of a flag in said hardware I/O command block to determine whether both said abort command and said target I/O command have completed.
2. The method of claim 1 further comprising:
scheduling said hardware I/O command block for execution by said host adapter following said modifying.
3. The method of claim 1 wherein said modifying does not affect information is said hardware I/O command block for said target I/O command.
4. The method of claim 1 wherein said modifying is performed by a host adapter manager executing on a host system.
5. The method of claim 1 wherein said modifying is performed by a sequencer of said host adapter.
6. The method of claim 1 further comprising:
notifying a host system of completion of both said abort command and said target I/O command when said flag has an asserted state.
7. The method of claim 6 further comprising:
leaving said flag asserted only following completion of execution of both said abort command and said target I/O command.
8. A method comprising:
receiving, by a host adapter, a hardware I/O command block including a target I/O command for a target I/O device;
modifying said hardware I/O command block to include an abort command;
scheduling said hardware I/O command block for execution by said host adapter following said modifying;
checking a state of a flag in said hardware I/O command block to determine whether both said abort command and said target I/O command have completed; and
notifying a host system of completion of both said abort command and said target I/O command when said flag has an asserted state.
9. The method of claim 8 wherein said modifying does not affect information is said hardware I/O command block for said target I/O command.
10. The method of claim 8 wherein said modifying is performed by a host adapter manager executing on a host system.
11. The method of claim 8 wherein said modifying is performed by a sequencer of said host adapter.
12. The method of claim 8 further comprising:
leaving said flag asserted only following completion of execution of both said abort command and said target I/O command.
13. A method comprising:
configuring a done flag in a hardware I/O control block, which includes a target I/O command, to a first state wherein said first state indicates said target I/O command has not been executed by a host adapter; and
configuring said hardware I/O control block to include an abort command for said target I/O command wherein said hardware I/O control block includes both said target I/O command and said abort command.
14. The method of claim 13 further comprising:
configuring said done flag to a second state upon completion of said target I/O command and said abort command.
15. The method of claim 13 further comprising:
scheduling said hardware I/O command block for execution by said host adapter following said configuring said hardware I/O control block to include said abort command.
16. The method of claim 13 further comprising:
determining whether both said abort command and said target I/O command have completed.
17. The method of claim 16 wherein said determining further comprises:
checking a state of said done flag in said hardware I/O command block.
18. The method of claim 17 further comprising:
notifying a host system of completion of both said abort command and said target I/O command when said done flag has a second state.
19. A method comprising:
configuring a done flag in a hardware I/O control block, which includes a target I/O command, to a first state wherein said first state indicates said target I/O command has not been executed by a host adapter;
configuring said hardware I/O control block to include an abort command for said target I/O command wherein said hardware I/O control block includes both said target I/O command and said abort command;
scheduling said hardware I/O command block for execution by said host adapter following said configuring said hardware I/O control block to include said abort command;
determining whether both said abort command and said target I/O command have completed; and
configuring said done flag to a second state upon completion of said target I/O command and said abort command.
20. The method of claim 19 wherein said determining further comprises:
checking a state of said done flag in said hardware I/O command block.
21. The method of claim 20 further comprising:
notifying a host system of completion of both said abort command and said target I/O command when said done flag has a second state.
22. A method comprising:
determining whether a hardware I/O command block including a target I/O command to be aborted is in a host adapter execution queue;
removing said hardware I/O command block from said execution queue upon said determining finding that said hardware I/O command block is in said host adapter execution queue; and
determining a state of a done flag in said hardware I/O command block upon said determining finding that said hardware I/O command block is not in said host adapter execution queue.
23. The method of claim 22 further comprising:
modifying said hardware I/O command block to include an abortion command for said target I/O command upon said determining said state of said done flag finding that said done flag is unasserted.
24. The method of claim 23 further comprising:
scheduling said hardware I/O command block for execution by said host adapter following said modifying said hardware I/O control block to include said abort command.
25. A method comprising:
using a single hardware I/O command block structure for both a target I/O command and an abortion command for said target I/O command; and
asserting a done flag in said single hardware I/O command block structure when both said target I/O command and said abortion command for said target I/O command are completed.