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| author | Jens Axboe | 2017-03-30 21:44:26 +0200 |
|---|---|---|
| committer | Jens Axboe | 2017-03-30 21:44:26 +0200 |
| commit | db5bcf87bb9e856e90c131d6e636a5550c2bbcd3 (patch) | |
| tree | a444271fa55e059a87263021575e7036dcef19af /drivers/block/null_blk.c | |
| parent | blk-mq: fix schedule-under-preempt for blocking drivers (diff) | |
| download | kernel-qcow2-linux-db5bcf87bb9e856e90c131d6e636a5550c2bbcd3.tar.gz kernel-qcow2-linux-db5bcf87bb9e856e90c131d6e636a5550c2bbcd3.tar.xz kernel-qcow2-linux-db5bcf87bb9e856e90c131d6e636a5550c2bbcd3.zip | |
null_blk: add blocking mode
This adds a new module parameter to null_blk, blocking. If set, null_blk
will set the BLK_MQ_F_BLOCKING flag, indicating that it sometimes/always
needs to block in its ->queue_rq() function. The intent is to help find
regressions in blocking drivers, since not many of them exist.
If null_blk is loaded with submit_queues > 1 and blocking=1, this
shows the regression recently fixed by bf4907c05e61.
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/block/null_blk.c')
| -rw-r--r-- | drivers/block/null_blk.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index 6f2e565bccc5..444f8d88f1a8 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -117,6 +117,10 @@ static bool use_lightnvm; module_param(use_lightnvm, bool, S_IRUGO); MODULE_PARM_DESC(use_lightnvm, "Register as a LightNVM device"); +static bool blocking; +module_param(blocking, bool, S_IRUGO); +MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device"); + static int irqmode = NULL_IRQ_SOFTIRQ; static int null_set_irqmode(const char *str, const struct kernel_param *kp) @@ -357,6 +361,8 @@ static int null_queue_rq(struct blk_mq_hw_ctx *hctx, { struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); + might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); + if (irqmode == NULL_IRQ_TIMER) { hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); cmd->timer.function = null_cmd_timer_expired; @@ -724,6 +730,9 @@ static int null_add_dev(void) nullb->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; nullb->tag_set.driver_data = nullb; + if (blocking) + nullb->tag_set.flags |= BLK_MQ_F_BLOCKING; + rv = blk_mq_alloc_tag_set(&nullb->tag_set); if (rv) goto out_cleanup_queues; |