@@ -117,6 +117,14 @@ static bool use_lightnvm;
module_param(use_lightnvm, bool, S_IRUGO);
MODULE_PARM_DESC(use_lightnvm, "Register as a LightNVM device");
+static bool use_sched;
+module_param(use_sched, bool, S_IRUGO);
+MODULE_PARM_DESC(use_sched, "Ask for blk-mq scheduling");
+
+static bool wc;
+module_param(wc, bool, S_IRUGO);
+MODULE_PARM_DESC(use_sched, "Claim volatile write cache");
+
static int irqmode = NULL_IRQ_SOFTIRQ;
static int null_set_irqmode(const char *str, const struct kernel_param *kp)
@@ -724,6 +732,9 @@ static int null_add_dev(void)
nullb->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
nullb->tag_set.driver_data = nullb;
+ if (use_sched)
+ nullb->tag_set.flags |= BLK_MQ_F_SQ_SCHED;
+
rv = blk_mq_alloc_tag_set(&nullb->tag_set);
if (rv)
goto out_cleanup_queues;
@@ -760,6 +771,9 @@ static int null_add_dev(void)
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, nullb->q);
queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, nullb->q);
+ if (wc)
+ blk_queue_write_cache(nullb->q, true, false);
+
mutex_lock(&lock);
nullb->index = nullb_indexes++;
mutex_unlock(&lock);
Signed-off-by: Jens Axboe <axboe@fb.com> --- drivers/block/null_blk.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)