Dequeuing from a host adapter two-dimensional queue
View Patent ↗A two-dimensional command block queue includes a plurality of command blocks in a first linked list. One of the command blocks in a string is included in the first linked list. The string is delimited by only a tail pointer stored in a tail pointer list. Following dequeuing the string for processing, a pointer to the one command block of the string that was in the common queue is included in a string head pointer list. The tail pointer to the string is not changed in the tail pointer list following dequeuing of the string. This allows any new SCBs to be appended to the end of the string, while the string is being processed. This allows streaming of new SCBs to an I/O device that had previously been selected and is still connected to the host adapter.
1. A method comprising:
dequeuing a string from a two dimensional command block queue wherein said string is a dequeued string and said dequeued string comprises a linked list of command blocks; and
appending a new command block to said dequeued string.
2. The method of claim 1 further comprising:
processing said dequeued string.
3. The method of claim 2 further comprising:
completing said processing of said dequeued string.
4. The method of claim 3 further comprising:
appending unprocessed commands blocks in said dequeued string to said two dimensional command block queue.
5. The method of claim 4 wherein a sequencer is used in said appending operations.
6. The method of claim 5 wherein another sequencer is used in said processing and stopping operations.
7. A method of managing command blocks comprising:
using a first sequencer to manage a two-dimensional command block queue including a plurality of strings of command blocks wherein each string of command blocks is a linked list; and
using a second sequencer to process a string of command blocks dequeued from said two-dimensional command block queue.
8. The method of claim 7 further comprising:
using said first sequencer to append a command block to said string of command blocks dequeued from said two-dimensional command block queue.