row: Adding support for reinsert already dispatched req

Add support for reinserting already dispatched request back to the
schedulers internal data structures.
The request will be reinserted back to the queue (head) it was
dispatched from as if it was never dispatched.

Change-Id: I70954df300774409c25b5821465fb3aa33d8feb5
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
This commit is contained in:
Tatyana Brokhman 2012-10-30 08:33:06 +02:00 committed by Stephen Boyd
parent 0a4d72a6fb
commit ade89fc539
1 changed files with 34 additions and 1 deletions

View File

@ -274,7 +274,39 @@ static void row_add_request(struct request_queue *q,
row_log_rowq(rd, rqueue->prio, "added request");
}
/*
/**
* row_reinsert_req() - Reinsert request back to the scheduler
* @q: requests queue
* @rq: request to add
*
* Reinsert the given request back to the queue it was
* dispatched from as if it was never dispatched.
*
* Returns 0 on success, error code otherwise
*/
static int row_reinsert_req(struct request_queue *q,
struct request *rq)
{
struct row_data *rd = q->elevator->elevator_data;
struct row_queue *rqueue = RQ_ROWQ(rq);
/* Verify rqueue is legitimate */
if (rqueue->prio >= ROWQ_MAX_PRIO) {
pr_err("\n\nROW BUG: row_reinsert_req() rqueue->prio = %d\n",
rqueue->prio);
blk_dump_rq_flags(rq, "");
return -EIO;
}
list_add(&rq->queuelist, &rqueue->fifo);
rd->nr_reqs[rq_data_dir(rq)]++;
row_log_rowq(rd, rqueue->prio, "request reinserted");
return 0;
}
/**
* row_remove_request() - Remove given request from scheduler
* @q: requests queue
* @rq: request to remove
@ -666,6 +698,7 @@ static struct elevator_type iosched_row = {
.elevator_merge_req_fn = row_merged_requests,
.elevator_dispatch_fn = row_dispatch_requests,
.elevator_add_req_fn = row_add_request,
.elevator_reinsert_req_fn = row_reinsert_req,
.elevator_former_req_fn = elv_rb_former_request,
.elevator_latter_req_fn = elv_rb_latter_request,
.elevator_set_req_fn = row_set_request,