Initial support for LightNVM. The support can be used to benchmark
performance of targets and core implementation.
Signed-off-by: Matias Bjørling <m...@lightnvm.io>
---
Documentation/block/null_blk.txt | 8 +++
drivers/block/null_blk.c | 138 +++++++++++++++++++++++++++++++++++++--
2 files changed, 140 insertions(+), 6 deletions(-)
diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt
index 2f6c6ff..a34f50a 100644
--- a/Documentation/block/null_blk.txt
+++ b/Documentation/block/null_blk.txt
@@ -70,3 +70,11 @@ use_per_node_hctx=[0/1]: Default: 0
parameter.
1: The multi-queue block layer is instantiated with a hardware dispatch
queue for each CPU node in the system.
+
+IV: LightNVM specific parameters
+
+nvm_enable=[x]: Default: 0
+ Enable LightNVM for null block devices. Requires blk-mq to be used.
+
+nvm_num_channels=[x]: Default: 1
+ Number of LightNVM channels that is exposed to the LightNVM driver.
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 69de41a..6531250 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -8,6 +8,7 @@
#include <linux/slab.h>
#include <linux/blk-mq.h>
#include <linux/hrtimer.h>
+#include <linux/lightnvm.h>
struct nullb_cmd {
struct list_head list;
@@ -147,6 +148,14 @@ static bool use_per_node_hctx = false;
module_param(use_per_node_hctx, bool, S_IRUGO);
MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware
context queues. Default: false");
+static bool nvm_enable;
+module_param(nvm_enable, bool, S_IRUGO);
+MODULE_PARM_DESC(nvm_enable, "Enable Open-channel SSD. Default: false");
+
+static int nvm_num_channels = 1;
+module_param(nvm_num_channels, int, S_IRUGO);
+MODULE_PARM_DESC(nvm_num_channels, "Number of channels to be exposed from the
Open-Channel SSD. Default: 1");
+
static void put_tag(struct nullb_queue *nq, unsigned int tag)
{
clear_bit_unlock(tag, nq->tag_map);
@@ -363,6 +372,110 @@ static void null_request_fn(struct request_queue *q)
}
}
+#ifdef CONFIG_NVM
+static int null_nvm_id(struct request_queue *q, struct nvm_id *id)
+{
+ sector_t size = gb * 1024 * 1024 * 1024ULL;
+ unsigned long per_chnl_size =
+ size / bs / nvm_num_channels;
+ struct nvm_id_chnl *chnl;
+ int i;
+
+ id->ver_id = 0x1;
+ id->nvm_type = NVM_NVMT_BLK;
+ id->nchannels = nvm_num_channels;
+
+ id->chnls = kmalloc_array(id->nchannels, sizeof(struct nvm_id_chnl),
+ GFP_KERNEL);
+ if (!id->chnls)
+ return -ENOMEM;
+
+ for (i = 0; i < id->nchannels; i++) {
+ chnl = &id->chnls[i];
+ chnl->queue_size = hw_queue_depth;
+ chnl->gran_read = bs;
+ chnl->gran_write = bs;
+ chnl->gran_erase = bs * 256;
+ chnl->oob_size = 0;
+ chnl->t_r = chnl->t_sqr = 25000; /* 25us */
+ chnl->t_w = chnl->t_sqw = 500000; /* 500us */
+ chnl->t_e = 1500000; /* 1.500us */
+ chnl->io_sched = NVM_IOSCHED_CHANNEL;
+ chnl->laddr_begin = per_chnl_size * i;
+ chnl->laddr_end = per_chnl_size * (i + 1) - 1;
+ }
+
+ return 0;
+}
+
+static int null_nvm_get_features(struct request_queue *q,
+ struct nvm_get_features *gf)
+{
+ gf->rsp = NVM_RSP_L2P;
+ gf->ext = 0;
+
+ return 0;
+}
+
+static void null_nvm_end_io(struct request *rq, int error)
+{
+ struct nvm_rq *rqd = rq->end_io_data;
+ struct nvm_tgt_instance *ins = rqd->ins;
+
+ ins->tt->end_io(rq->end_io_data, error);
+
+ blk_put_request(rq);
+}
+
+static int null_nvm_submit_io(struct request_queue *q, struct nvm_rq *rqd)
+{
+ struct request *rq;
+ struct bio *bio = rqd->bio;
+
+ rq = blk_mq_alloc_request(q, bio_rw(bio), GFP_KERNEL, 0);
+ if (IS_ERR(rq))
+ return -ENOMEM;
+
+ rq->cmd_type = REQ_TYPE_DRV_PRIV;
+ rq->__sector = bio->bi_iter.bi_sector;
+ rq->ioprio = bio_prio(bio);
+
+ if (bio_has_data(bio))
+ rq->nr_phys_segments = bio_phys_segments(q, bio);
+
+ rq->__data_len = bio->bi_iter.bi_size;
+ rq->bio = rq->biotail = bio;
+
+ rq->end_io_data = rqd;
+
+ blk_execute_rq_nowait(q, NULL, rq, 0, null_nvm_end_io);
+
+ return 0;
+}
+
+static struct nvm_dev_ops null_nvm_dev_ops = {
+ .identify = null_nvm_id,
+ .get_features = null_nvm_get_features,
+ .submit_io = null_nvm_submit_io,
+};
+
+static int null_nvm_register(struct nullb *nullb, struct gendisk *disk)
+{
+ return nvm_register(nullb->q, disk, &null_nvm_dev_ops);
+}
+
+static void null_nvm_unregister(struct gendisk *disk)
+{
+ nvm_unregister(disk);
+}
+#else
+static int null_nvm_register(struct nullb *nullb, struct gendisk *disk)
+{
+ return -EINVAL;
+}
+static void null_nvm_unregister(struct gendisk *disk) { }
+#endif /* CONFIG_NVM */
+
static int null_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
@@ -410,6 +523,9 @@ static void null_del_dev(struct nullb *nullb)
{
list_del_init(&nullb->list);
+ if (nvm_enable)
+ null_nvm_unregister(nullb->disk);
+
del_gendisk(nullb->disk);
blk_cleanup_queue(nullb->q);
if (queue_mode == NULL_Q_MQ)
@@ -579,11 +695,6 @@ static int null_add_dev(void)
goto out_cleanup_blk_queue;
}
- mutex_lock(&lock);
- list_add_tail(&nullb->list, &nullb_list);
- nullb->index = nullb_indexes++;
- mutex_unlock(&lock);
-
blk_queue_logical_block_size(nullb->q, bs);
blk_queue_physical_block_size(nullb->q, bs);
@@ -598,9 +709,24 @@ static int null_add_dev(void)
disk->private_data = nullb;
disk->queue = nullb->q;
sprintf(disk->disk_name, "nullb%d", nullb->index);
- add_disk(disk);
+
+ if (nvm_enable) {
+ rv = null_nvm_register(nullb, disk);
+ if (rv)
+ goto out_cleanup_disk;
+ } else {
+ add_disk(disk);
+ }
+
+ mutex_lock(&lock);
+ list_add_tail(&nullb->list, &nullb_list);
+ nullb->index = nullb_indexes++;
+ mutex_unlock(&lock);
+
return 0;
+out_cleanup_disk:
+ put_disk(disk);
out_cleanup_blk_queue:
blk_cleanup_queue(nullb->q);
out_cleanup_tags:
--
2.1.4
--
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