[PATCH 17/17] null_blk: remove legacy IO path

Jens Axboe
2018-10-11T16:59:09Z

We're planning on removing this code completely, kill the old
path.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
drivers/block/null_blk_main.c | 96 +++--------------------------------
1 file changed, 6 insertions(+), 90 deletions(-)

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 093b614d6524..8142cc8ff952 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -616,10 +616,6 @@ static void end_cmd(struct nullb_cmd *cmd)
case NULL_Q_MQ:
blk_mq_end_request(cmd->rq, cmd->error);
return;
- case NULL_Q_RQ:
- INIT_LIST_HEAD(&cmd->rq->queuelist);
- blk_end_request_all(cmd->rq, cmd->error);
- break;
case NULL_Q_BIO:
cmd->bio->bi_status = cmd->error;
bio_endio(cmd->bio);
@@ -627,15 +623,6 @@ static void end_cmd(struct nullb_cmd *cmd)
}

free_cmd(cmd);
-
- /* Restart queue if needed, as we are freeing a tag */
- if (queue_mode == NULL_Q_RQ && blk_queue_stopped(q)) {
- unsigned long flags;
-
- spin_lock_irqsave(q->queue_lock, flags);
- blk_start_queue_async(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
- }
}

static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
@@ -1197,17 +1184,8 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
/* race with timer */
if (atomic_long_read(&nullb->cur_bytes) > 0)
null_restart_queue_async(nullb);
- if (dev->queue_mode == NULL_Q_RQ) {
- struct request_queue *q = nullb->q;
-
- spin_lock_irq(q->queue_lock);
- rq->rq_flags |= RQF_DONTPREP;
- blk_requeue_request(q, rq);
- spin_unlock_irq(q->queue_lock);
- return BLK_STS_OK;
- } else
- /* requeue request */
- return BLK_STS_DEV_RESOURCE;
+ /* requeue request */
+ return BLK_STS_DEV_RESOURCE;
}
}

@@ -1278,9 +1256,6 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
case NULL_Q_MQ:
blk_mq_complete_request(cmd->rq);
break;
- case NULL_Q_RQ:
- blk_complete_request(cmd->rq);
- break;
case NULL_Q_BIO:
/*
* XXX: no proper submitting cpu information available.
@@ -1349,30 +1324,6 @@ static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
return BLK_QC_T_NONE;
}

-static enum blk_eh_timer_return null_rq_timed_out_fn(struct request *rq)
-{
- pr_info("null: rq %p timed out\n", rq);
- __blk_complete_request(rq);
- return BLK_EH_DONE;
-}
-
-static int null_rq_prep_fn(struct request_queue *q, struct request *req)
-{
- struct nullb *nullb = q->queuedata;
- struct nullb_queue *nq = nullb_to_queue(nullb);
- struct nullb_cmd *cmd;
-
- cmd = alloc_cmd(nq, 0);
- if (cmd) {
- cmd->rq = req;
- req->special = cmd;
- return BLKPREP_OK;
- }
- blk_stop_queue(q);
-
- return BLKPREP_DEFER;
-}
-
static bool should_timeout_request(struct request *rq)
{
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
@@ -1391,27 +1342,6 @@ static bool should_requeue_request(struct request *rq)
return false;
}

-static void null_request_fn(struct request_queue *q)
-{
- struct request *rq;
-
- while ((rq = blk_fetch_request(q)) != NULL) {
- struct nullb_cmd *cmd = rq->special;
-
- /* just ignore the request */
- if (should_timeout_request(rq))
- continue;
- if (should_requeue_request(rq)) {
- blk_requeue_request(q, rq);
- continue;
- }
-
- spin_unlock_irq(q->queue_lock);
- null_handle_cmd(cmd);
- spin_lock_irq(q->queue_lock);
- }
-}
-
static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
{
pr_info("null: rq %p timed out\n", rq);
@@ -1766,24 +1696,6 @@ static int null_add_dev(struct nullb_device *dev)
rv = init_driver_queues(nullb);
if (rv)
goto out_cleanup_blk_queue;
- } else {
- nullb->q = blk_init_queue_node(null_request_fn, &nullb->lock,
- dev->home_node);
- if (!nullb->q) {
- rv = -ENOMEM;
- goto out_cleanup_queues;
- }
-
- if (!null_setup_fault())
- goto out_cleanup_blk_queue;
-
- blk_queue_prep_rq(nullb->q, null_rq_prep_fn);
- blk_queue_softirq_done(nullb->q, null_softirq_done_fn);
- blk_queue_rq_timed_out(nullb->q, null_rq_timed_out_fn);
- nullb->q->rq_timeout = 5 * HZ;
- rv = init_driver_queues(nullb);
- if (rv)
- goto out_cleanup_blk_queue;
}

if (dev->mbps) {
@@ -1865,6 +1777,10 @@ static int __init null_init(void)
return -EINVAL;
}

+ if (g_queue_mode == NULL_Q_RQ) {
+ pr_err("null_blk: legacy IO path no longer available\n");
+ return -EINVAL;
+ }
if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
if (g_submit_queues != nr_online_nodes) {
pr_warn("null_blk: submit_queues param is set to %u.\n",
--
2.17.1