From: Dongsheng Yang <dongsheng.yang.linux@xxxxxxxxx>
The "cbd_blkdev" represents a virtual block device named "/dev/cbdX". It
corresponds to a backend. The "blkdev" interacts with upper-layer users
and accepts IO requests from them. A "blkdev" includes multiple
"cbd_queues", each of which requires a "cbd_channel" to
interact with the backend's handler. The "cbd_queue" forwards IO
requests from the upper layer to the backend's handler through the
channel.
Signed-off-by: Dongsheng Yang <dongsheng.yang.linux@xxxxxxxxx>
---
drivers/block/cbd/Makefile | 2 +-
drivers/block/cbd/cbd_blkdev.c | 375 ++++++++++++++++++
drivers/block/cbd/cbd_main.c | 6 +
drivers/block/cbd/cbd_queue.c | 621 ++++++++++++++++++++++++++++++
drivers/block/cbd/cbd_transport.c | 11 +
5 files changed, 1014 insertions(+), 1 deletion(-)
create mode 100644 drivers/block/cbd/cbd_blkdev.c
create mode 100644 drivers/block/cbd/cbd_queue.c
diff --git a/drivers/block/cbd/Makefile b/drivers/block/cbd/Makefile
index b47f1e584946..f5fb5fd68f3d 100644
--- a/drivers/block/cbd/Makefile
+++ b/drivers/block/cbd/Makefile
@@ -1,3 +1,3 @@
-cbd-y := cbd_main.o cbd_transport.o cbd_channel.o cbd_host.o cbd_backend.o cbd_handler.o
+cbd-y := cbd_main.o cbd_transport.o cbd_channel.o cbd_host.o cbd_backend.o cbd_handler.o cbd_blkdev.o cbd_queue.o
obj-$(CONFIG_BLK_DEV_CBD) += cbd.o
diff --git a/drivers/block/cbd/cbd_blkdev.c b/drivers/block/cbd/cbd_blkdev.c
new file mode 100644
index 000000000000..816bc28afb49
--- /dev/null
+++ b/drivers/block/cbd/cbd_blkdev.c
@@ -0,0 +1,375 @@
+#include "cbd_internal.h"
+
+static ssize_t blkdev_backend_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_blkdev_device *blkdev;
+ struct cbd_blkdev_info *blkdev_info;
+
+ blkdev = container_of(dev, struct cbd_blkdev_device, dev);
+ blkdev_info = blkdev->blkdev_info;
+
+ cbdt_flush_range(blkdev->cbdt, blkdev_info, sizeof(*blkdev_info));
+
+ if (blkdev_info->state == cbd_blkdev_state_none)
+ return 0;
+
+ return sprintf(buf, "%u\n", blkdev_info->backend_id);
+}
+
+static DEVICE_ATTR(backend_id, 0400, blkdev_backend_id_show, NULL);
+
+static ssize_t blkdev_host_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_blkdev_device *blkdev;
+ struct cbd_blkdev_info *blkdev_info;
+
+ blkdev = container_of(dev, struct cbd_blkdev_device, dev);
+ blkdev_info = blkdev->blkdev_info;
+
+ cbdt_flush_range(blkdev->cbdt, blkdev_info, sizeof(*blkdev_info));
+
+ if (blkdev_info->state == cbd_blkdev_state_none)
+ return 0;
+
+ return sprintf(buf, "%u\n", blkdev_info->host_id);
+}
+
+static DEVICE_ATTR(host_id, 0400, blkdev_host_id_show, NULL);
+
+static ssize_t blkdev_mapped_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_blkdev_device *blkdev;
+ struct cbd_blkdev_info *blkdev_info;
+
+ blkdev = container_of(dev, struct cbd_blkdev_device, dev);
+ blkdev_info = blkdev->blkdev_info;
+
+ cbdt_flush_range(blkdev->cbdt, blkdev_info, sizeof(*blkdev_info));
+
+ if (blkdev_info->state == cbd_blkdev_state_none)
+ return 0;
+
+ return sprintf(buf, "%u\n", blkdev_info->mapped_id);
+}
+
+static DEVICE_ATTR(mapped_id, 0400, blkdev_mapped_id_show, NULL);
+
+CBD_OBJ_HEARTBEAT(blkdev);
+
+static struct attribute *cbd_blkdev_attrs[] = {
+ &dev_attr_mapped_id.attr,
+ &dev_attr_host_id.attr,
+ &dev_attr_backend_id.attr,
+ &dev_attr_alive.attr,
+ NULL
+};
+
+static struct attribute_group cbd_blkdev_attr_group = {
+ .attrs = cbd_blkdev_attrs,
+};
+
+static const struct attribute_group *cbd_blkdev_attr_groups[] = {
+ &cbd_blkdev_attr_group,
+ NULL
+};
+
+static void cbd_blkdev_release(struct device *dev)
+{
+}
+
+struct device_type cbd_blkdev_type = {
+ .name = "cbd_blkdev",
+ .groups = cbd_blkdev_attr_groups,
+ .release = cbd_blkdev_release,
+};
+
+struct device_type cbd_blkdevs_type = {
+ .name = "cbd_blkdevs",
+ .release = cbd_blkdev_release,
+};
+
+
+static int cbd_major;
+static DEFINE_IDA(cbd_mapped_id_ida);
+
+static int minor_to_cbd_mapped_id(int minor)
+{
+ return minor >> CBD_PART_SHIFT;
+}
+
+
+static int cbd_open(struct gendisk *disk, blk_mode_t mode)
+{
+ return 0;
+}
+
+static void cbd_release(struct gendisk *disk)
+{
+}
+
+static const struct block_device_operations cbd_bd_ops = {
+ .owner = THIS_MODULE,
+ .open = cbd_open,
+ .release = cbd_release,
+};
+
+
+static void cbd_blkdev_destroy_queues(struct cbd_blkdev *cbd_blkdev)
+{
+ int i;
+
+ for (i = 0; i < cbd_blkdev->num_queues; i++) {
+ cbd_queue_stop(&cbd_blkdev->queues[i]);
+ }
+
+ kfree(cbd_blkdev->queues);
+}
+
+static int cbd_blkdev_create_queues(struct cbd_blkdev *cbd_blkdev)
+{
+ int i;
+ int ret;
+ struct cbd_queue *cbdq;
+
+ cbd_blkdev->queues = kcalloc(cbd_blkdev->num_queues, sizeof(struct cbd_queue), GFP_KERNEL);
+ if (!cbd_blkdev->queues) {
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < cbd_blkdev->num_queues; i++) {
+ cbdq = &cbd_blkdev->queues[i];
+ cbdq->cbd_blkdev = cbd_blkdev;
+ cbdq->index = i;
+ ret = cbd_queue_start(cbdq);
+ if (ret)
+ goto err;
+
+ }
+
+ return 0;
+err:
+ cbd_blkdev_destroy_queues(cbd_blkdev);
+ return ret;
+}
+
+static int disk_start(struct cbd_blkdev *cbd_blkdev)
+{
+ int ret;
+ struct gendisk *disk;
+
+ memset(&cbd_blkdev->tag_set, 0, sizeof(cbd_blkdev->tag_set));
+ cbd_blkdev->tag_set.ops = &cbd_mq_ops;
+ cbd_blkdev->tag_set.queue_depth = 128;
+ cbd_blkdev->tag_set.numa_node = NUMA_NO_NODE;
+ cbd_blkdev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_NO_SCHED;
+ cbd_blkdev->tag_set.nr_hw_queues = cbd_blkdev->num_queues;
+ cbd_blkdev->tag_set.cmd_size = sizeof(struct cbd_request);
+ cbd_blkdev->tag_set.timeout = 0;
+ cbd_blkdev->tag_set.driver_data = cbd_blkdev;
+
+ ret = blk_mq_alloc_tag_set(&cbd_blkdev->tag_set);
+ if (ret) {
+ pr_err("failed to alloc tag set %d", ret);
+ goto err;
+ }
+
+ disk = blk_mq_alloc_disk(&cbd_blkdev->tag_set, cbd_blkdev);
+ if (IS_ERR(disk)) {
+ ret = PTR_ERR(disk);
+ pr_err("failed to alloc disk");
+ goto out_tag_set;
+ }
+
+ snprintf(disk->disk_name, sizeof(disk->disk_name), "cbd%d",
+ cbd_blkdev->mapped_id);
+
+ disk->major = cbd_major;
+ disk->first_minor = cbd_blkdev->mapped_id << CBD_PART_SHIFT;
+ disk->minors = (1 << CBD_PART_SHIFT);
+
+ disk->fops = &cbd_bd_ops;
+ disk->private_data = cbd_blkdev;
+
+ /* Tell the block layer that this is not a rotational device */
+ blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
+ blk_queue_flag_set(QUEUE_FLAG_SYNCHRONOUS, disk->queue);
+ blk_queue_flag_set(QUEUE_FLAG_NOWAIT, disk->queue);
+
+ blk_queue_physical_block_size(disk->queue, PAGE_SIZE);
+ blk_queue_max_hw_sectors(disk->queue, 128);
+ blk_queue_max_segments(disk->queue, USHRT_MAX);
+ blk_queue_max_segment_size(disk->queue, UINT_MAX);
+ blk_queue_io_min(disk->queue, 4096);
+ blk_queue_io_opt(disk->queue, 4096);
+
+ disk->queue->limits.max_sectors = queue_max_hw_sectors(disk->queue);
+ /* TODO support discard */
+ disk->queue->limits.discard_granularity = 0;
+ blk_queue_max_discard_sectors(disk->queue, 0);
+ blk_queue_max_write_zeroes_sectors(disk->queue, 0);
+
+ cbd_blkdev->disk = disk;
+
+ cbdt_add_blkdev(cbd_blkdev->cbdt, cbd_blkdev);
+ cbd_blkdev->blkdev_info->mapped_id = cbd_blkdev->blkdev_id;
+ cbd_blkdev->blkdev_info->state = cbd_blkdev_state_running;
+
+ set_capacity(cbd_blkdev->disk, cbd_blkdev->dev_size);
+
+ set_disk_ro(cbd_blkdev->disk, false);
+ blk_queue_write_cache(cbd_blkdev->disk->queue, false, false);
+
+ ret = add_disk(cbd_blkdev->disk);
+ if (ret) {
+ goto put_disk;
+ }
+
+ ret = sysfs_create_link(&disk_to_dev(cbd_blkdev->disk)->kobj,
+ &cbd_blkdev->blkdev_dev->dev.kobj, "cbd_blkdev");
+ if (ret) {
+ goto del_disk;
+ }
+
+ blk_put_queue(cbd_blkdev->disk->queue);
+
+ return 0;
+
+del_disk:
+ del_gendisk(cbd_blkdev->disk);
+put_disk:
+ put_disk(cbd_blkdev->disk);
+out_tag_set:
+ blk_mq_free_tag_set(&cbd_blkdev->tag_set);
+err:
+ return ret;
+}
+
+int cbd_blkdev_start(struct cbd_transport *cbdt, u32 backend_id, u32 queues)
+{
+ struct cbd_blkdev *cbd_blkdev;
+ struct cbd_backend_info *backend_info;
+ u64 dev_size;
+ int ret;
+
+ backend_info = cbdt_get_backend_info(cbdt, backend_id);
+ cbdt_flush_range(cbdt, backend_info, sizeof(*backend_info));
+ if (backend_info->blkdev_count == CBDB_BLKDEV_COUNT_MAX) {
+ return -EBUSY;
+ }
+
+ dev_size = backend_info->dev_size;
+
+ cbd_blkdev = kzalloc(sizeof(struct cbd_blkdev), GFP_KERNEL);
+ if (!cbd_blkdev) {
+ pr_err("fail to alloc cbd_blkdev");
+ return -ENOMEM;
+ }
+
+ ret = cbdt_get_empty_blkdev_id(cbdt, &cbd_blkdev->blkdev_id);
+ if (ret < 0) {
+ goto blkdev_free;
+ }
+
+ cbd_blkdev->mapped_id = ida_simple_get(&cbd_mapped_id_ida, 0,
+ minor_to_cbd_mapped_id(1 << MINORBITS),
+ GFP_KERNEL);
+ if (cbd_blkdev->mapped_id < 0) {
+ ret = -ENOENT;
+ goto blkdev_free;
+ }
+
+ INIT_LIST_HEAD(&cbd_blkdev->node);
+ cbd_blkdev->cbdt = cbdt;
+ cbd_blkdev->backend_id = backend_id;
+ cbd_blkdev->num_queues = queues;
+ cbd_blkdev->dev_size = dev_size;
+ cbd_blkdev->blkdev_info = cbdt_get_blkdev_info(cbdt, cbd_blkdev->blkdev_id);
+ cbd_blkdev->blkdev_dev = &cbdt->cbd_blkdevs_dev->blkdev_devs[cbd_blkdev->blkdev_id];
+
+ cbd_blkdev->blkdev_info->state = cbd_blkdev_state_running;
+ cbdt_flush_range(cbdt, cbd_blkdev->blkdev_info, sizeof(*cbd_blkdev->blkdev_info));
+
+ INIT_DELAYED_WORK(&cbd_blkdev->hb_work, blkdev_hb_workfn);
+ queue_delayed_work(cbd_wq, &cbd_blkdev->hb_work, 0);
+
+ ret = cbd_blkdev_create_queues(cbd_blkdev);
+ if (ret < 0) {
+ goto cancel_hb;;
+ }
+
+ ret = disk_start(cbd_blkdev);
+ if (ret < 0) {
+ goto destroy_queues;
+ }
+
+ backend_info->blkdev_count++;
+ cbdt_flush_range(cbdt, backend_info, sizeof(*backend_info));
+
+ return 0;
+
+destroy_queues:
+ cbd_blkdev_destroy_queues(cbd_blkdev);
+cancel_hb:
+ cancel_delayed_work_sync(&cbd_blkdev->hb_work);
+ cbd_blkdev->blkdev_info->state = cbd_blkdev_state_none;
+ cbdt_flush_range(cbdt, cbd_blkdev->blkdev_info, sizeof(*cbd_blkdev->blkdev_info));
+ ida_simple_remove(&cbd_mapped_id_ida, cbd_blkdev->mapped_id);
+blkdev_free:
+ kfree(cbd_blkdev);
+ return ret;
+}
+
+static void disk_stop(struct cbd_blkdev *cbd_blkdev)
+{
+ sysfs_remove_link(&disk_to_dev(cbd_blkdev->disk)->kobj, "cache");
+ del_gendisk(cbd_blkdev->disk);
+ put_disk(cbd_blkdev->disk);
+ blk_mq_free_tag_set(&cbd_blkdev->tag_set);
+}
+
+int cbd_blkdev_stop(struct cbd_transport *cbdt, u32 devid)
+{
+ struct cbd_blkdev *cbd_blkdev;
+ struct cbd_backend_info *backend_info;
+
+ cbd_blkdev = cbdt_fetch_blkdev(cbdt, devid);
+ if (!cbd_blkdev) {
+ return -EINVAL;
+ }
+
+ backend_info = cbdt_get_backend_info(cbdt, cbd_blkdev->backend_id);
+
+ disk_stop(cbd_blkdev);
+ cbd_blkdev_destroy_queues(cbd_blkdev);
+ cancel_delayed_work_sync(&cbd_blkdev->hb_work);
+ cbd_blkdev->blkdev_info->state = cbd_blkdev_state_none;
+ cbdt_flush_range(cbdt, cbd_blkdev->blkdev_info, sizeof(*cbd_blkdev->blkdev_info));
+ ida_simple_remove(&cbd_mapped_id_ida, cbd_blkdev->mapped_id);
+
+ kfree(cbd_blkdev);
+
+ backend_info->blkdev_count--;
+ cbdt_flush_range(cbdt, backend_info, sizeof(*backend_info));
+
+ return 0;
+}
+
+int cbd_blkdev_init(void)
+{
+ cbd_major = register_blkdev(0, "cbd");
+ if (cbd_major < 0)
+ return cbd_major;
+
+ return 0;
+}
+
+void cbd_blkdev_exit(void)
+{
+ unregister_blkdev(cbd_major, "cbd");
+}
diff --git a/drivers/block/cbd/cbd_main.c b/drivers/block/cbd/cbd_main.c
index 8cfa60dde7c5..658233807b59 100644
--- a/drivers/block/cbd/cbd_main.c
+++ b/drivers/block/cbd/cbd_main.c
@@ -195,6 +195,11 @@ static int __init cbd_init(void)
goto device_unregister;
}
+ ret = cbd_blkdev_init();
+ if (ret < 0) {
+ goto bus_unregister;
+ }
+
return 0;
bus_unregister:
@@ -209,6 +214,7 @@ static int __init cbd_init(void)
static void cbd_exit(void)
{
+ cbd_blkdev_exit();
bus_unregister(&cbd_bus_type);
device_unregister(&cbd_root_dev);
diff --git a/drivers/block/cbd/cbd_queue.c b/drivers/block/cbd/cbd_queue.c
new file mode 100644
index 000000000000..6709ac016e18
--- /dev/null
+++ b/drivers/block/cbd/cbd_queue.c
@@ -0,0 +1,621 @@
+#include "cbd_internal.h"
+
+/*
+ * How do blkdev and backend interact through the channel?
+ * a) For reader side, before reading the data, if the data in this channel may
+ * be modified by the other party, then I need to flush the cache before reading to ensure
+ * that I get the latest data. For example, the blkdev needs to flush the cache before
+ * obtaining compr_head because compr_head will be updated by the backend handler.
+ * b) For writter side, if the written information will be read by others, then
+ * after writing, I need to flush the cache to let the other party see it immediately.
+ * For example, after blkdev submits cbd_se, it needs to update cmd_head to let the
+ * handler have a new cbd_se. Therefore, after updating cmd_head, I need to flush the
+ * cache to let the backend see it.
+ *
+ * For the blkdev queue, I am the only one who updates the `cmd_head`, `cmd_tail`, and `compr_tail'.
+ * Therefore, I don't need to flush_dcache before reading these data. However, after updating these data,
+ * I need to flush_dcache so that the backend handler can see these updates.
+ *
+ * On the other hand, `compr_head` is updated by the backend handler. So, I need to flush_dcache before
+ * reading `compr_head` to ensure that I can see the updates.
+ *
+ * ┌───────────┐ ┌─────────────┐
+ * │ blkdev │ │ backend │
+ * │ queue │ │ handler │
+ * └─────┬─────┘ └──────┬──────┘
+ * ▼ │
+ * init data and cbd_se │
+ * │ │
+ * ▼ │
+ * update cmd_head │
+ * │ │
+ * ▼ │
+ * flush_cache │
+ * │ ▼
+ * │ flush_cache
+ * │ │
+ * │ ▼
+ * │ handle cmd
+ * │ │
+ * │ ▼
+ * │ fill cbd_ce
+ * │ │
+ * │ ▼
+ * │ flush_cache
+ * ▼
+ * flush_cache
+ * │
+ * ▼
+ * complete_req
+ */
+
+static inline struct cbd_se *get_submit_entry(struct cbd_queue *cbdq)
+{
+ return (struct cbd_se *)(cbdq->channel.cmdr + cbdq->channel_info->cmd_head);
+}
+
+static inline struct cbd_se *get_oldest_se(struct cbd_queue *cbdq)
+{
+ if (cbdq->channel_info->cmd_tail == cbdq->channel_info->cmd_head)
+ return NULL;
+
+ return (struct cbd_se *)(cbdq->channel.cmdr + cbdq->channel_info->cmd_tail);
+}
+
+static inline struct cbd_ce *get_complete_entry(struct cbd_queue *cbdq)
+{
+ if (cbdq->channel_info->compr_tail == cbdq->channel_info->compr_head)
+ return NULL;
+
+ return (struct cbd_ce *)(cbdq->channel.compr + cbdq->channel_info->compr_tail);
+}
+
+static void cbd_req_init(struct cbd_queue *cbdq, enum cbd_op op, struct request *rq)
+{
+ struct cbd_request *cbd_req = blk_mq_rq_to_pdu(rq);
+
+ cbd_req->req = rq;
+ cbd_req->cbdq = cbdq;
+ cbd_req->op = op;
+
+ return;
+}
+
+static bool cbd_req_nodata(struct cbd_request *cbd_req)
+{
+ switch (cbd_req->op) {
+ case CBD_OP_WRITE:
+ case CBD_OP_READ:
+ return false;
+ case CBD_OP_DISCARD:
+ case CBD_OP_WRITE_ZEROS:
+ case CBD_OP_FLUSH:
+ return true;
+ default:
+ BUG();
+ }
+}
+
+static uint32_t cbd_req_segments(struct cbd_request *cbd_req)
+{
+ uint32_t segs = 0;
+ struct bio *bio = cbd_req->req->bio;
+
+ if (cbd_req_nodata(cbd_req))
+ return 0;
+
+ while (bio) {
+ segs += bio_segments(bio);
+ bio = bio->bi_next;
+ }
+
+ return segs;
+}
+
+static inline size_t cbd_get_cmd_size(struct cbd_request *cbd_req)
+{
+ u32 segs = cbd_req_segments(cbd_req);
+ u32 cmd_size = sizeof(struct cbd_se) + (sizeof(struct iovec) * segs);
+
+ return round_up(cmd_size, CBD_OP_ALIGN_SIZE);
+}
+
+static void insert_padding(struct cbd_queue *cbdq, u32 cmd_size)
+{
+ struct cbd_se_hdr *header;
+ u32 pad_len;
+
+ if (cbdq->channel_info->cmdr_size - cbdq->channel_info->cmd_head >= cmd_size)
+ return;
+
+ pad_len = cbdq->channel_info->cmdr_size - cbdq->channel_info->cmd_head;
+ cbd_queue_debug(cbdq, "insert pad:%d\n", pad_len);
+
+ header = (struct cbd_se_hdr *)get_submit_entry(cbdq);
+ memset(header, 0, pad_len);
+ cbd_se_hdr_set_op(&header->len_op, CBD_OP_PAD);
+ cbd_se_hdr_set_len(&header->len_op, pad_len);
+
+ cbdt_flush_range(cbdq->cbd_blkdev->cbdt, header, sizeof(*header));
+
+ CBDC_UPDATE_CMDR_HEAD(cbdq->channel_info->cmd_head, pad_len, cbdq->channel_info->cmdr_size);
+}
+
+static void queue_req_se_init(struct cbd_request *cbd_req)
+{
+ struct cbd_se *se;
+ struct cbd_se_hdr *header;
+ u64 offset = (u64)blk_rq_pos(cbd_req->req) << SECTOR_SHIFT;
+ u64 length = blk_rq_bytes(cbd_req->req);
+
+ se = get_submit_entry(cbd_req->cbdq);
+ memset(se, 0, cbd_get_cmd_size(cbd_req));
+ header = &se->header;
+
+ cbd_se_hdr_set_op(&header->len_op, cbd_req->op);
+ cbd_se_hdr_set_len(&header->len_op, cbd_get_cmd_size(cbd_req));
+
+ se->priv_data = cbd_req->req_tid;
+ se->offset = offset;
+ se->len = length;
+
+ if (req_op(cbd_req->req) == REQ_OP_READ || req_op(cbd_req->req) == REQ_OP_WRITE) {
+ se->data_off = cbd_req->cbdq->channel.data_head;
+ se->data_len = length;
+ }
+
+ cbd_req->se = se;
+}
+
+static bool data_space_enough(struct cbd_queue *cbdq, struct cbd_request *cbd_req)
+{
+ u32 space_available;
+ u32 space_needed;
+ u32 space_used;
+ u32 space_max;
+
+ space_max = cbdq->channel.data_size - 4096;
+
+ if (cbdq->channel.data_head > cbdq->channel.data_tail)
+ space_used = cbdq->channel.data_head - cbdq->channel.data_tail;
+ else if (cbdq->channel.data_head < cbdq->channel.data_tail)
+ space_used = cbdq->channel.data_head + (cbdq->channel.data_size - cbdq->channel.data_tail);
+ else
+ space_used = 0;
+
+ space_available = space_max - space_used;
+
+ space_needed = round_up(cbd_req->data_len, 4096);
+
+ if (space_available < space_needed) {
+ cbd_queue_err(cbdq, "data space is not enough: availaible: %u needed: %u",
+ space_available, space_needed);
+ return false;
+ }
+
+ return true;
+}
+
+static bool submit_ring_space_enough(struct cbd_queue *cbdq, u32 cmd_size)
+{
+ u32 space_available;
+ u32 space_needed;
+ u32 space_max, space_used;
+
+ /* There is a CMDR_RESERVED we dont use to prevent the ring to be used up */
+ space_max = cbdq->channel_info->cmdr_size - CBDC_CMDR_RESERVED;
+
+ if (cbdq->channel_info->cmd_head > cbdq->channel_info->cmd_tail)
+ space_used = cbdq->channel_info->cmd_head - cbdq->channel_info->cmd_tail;
+ else if (cbdq->channel_info->cmd_head < cbdq->channel_info->cmd_tail)
+ space_used = cbdq->channel_info->cmd_head + (cbdq->channel_info->cmdr_size - cbdq->channel_info->cmd_tail);
+ else
+ space_used = 0;
+
+ space_available = space_max - space_used;
+
+ if (cbdq->channel_info->cmdr_size - cbdq->channel_info->cmd_head > cmd_size)
+ space_needed = cmd_size;
+ else
+ space_needed = cmd_size + cbdq->channel_info->cmdr_size - cbdq->channel_info->cmd_head;
+
+ if (space_available < space_needed)
+ return false;
+
+ return true;
+}
+
+static void queue_req_data_init(struct cbd_request *cbd_req)
+{
+ struct cbd_queue *cbdq = cbd_req->cbdq;
+ struct bio *bio = cbd_req->req->bio;
+
+ if (cbd_req->op == CBD_OP_READ) {
+ goto advance_data_head;
+ }
+
+ cbdc_copy_from_bio(&cbdq->channel, cbd_req->data_off, cbd_req->data_len, bio);
+
+advance_data_head:
+ cbdq->channel.data_head = round_up(cbdq->channel.data_head + cbd_req->data_len, PAGE_SIZE);
+ cbdq->channel.data_head %= cbdq->channel.data_size;
+
+ return;
+}
+
+static void complete_inflight_req(struct cbd_queue *cbdq, struct cbd_request *cbd_req, int ret);
+static void cbd_queue_fn(struct cbd_request *cbd_req)
+{
+ struct cbd_queue *cbdq = cbd_req->cbdq;
+ int ret = 0;
+ size_t command_size;
+
+ spin_lock(&cbdq->inflight_reqs_lock);
+ list_add_tail(&cbd_req->inflight_reqs_node, &cbdq->inflight_reqs);
+ spin_unlock(&cbdq->inflight_reqs_lock);
+
+ command_size = cbd_get_cmd_size(cbd_req);
+
+ spin_lock(&cbdq->channel.cmdr_lock);
+ if (req_op(cbd_req->req) == REQ_OP_WRITE || req_op(cbd_req->req) == REQ_OP_READ) {
+ cbd_req->data_off = cbdq->channel.data_head;
+ cbd_req->data_len = blk_rq_bytes(cbd_req->req);
+ } else {
+ cbd_req->data_off = -1;
+ cbd_req->data_len = 0;
+ }
+
+ if (!submit_ring_space_enough(cbdq, command_size) ||
+ !data_space_enough(cbdq, cbd_req)) {
+ spin_unlock(&cbdq->channel.cmdr_lock);
+
+ /* remove request from inflight_reqs */
+ spin_lock(&cbdq->inflight_reqs_lock);
+ list_del_init(&cbd_req->inflight_reqs_node);
+ spin_unlock(&cbdq->inflight_reqs_lock);
+
+ cbd_blk_debug(cbdq->cbd_blkdev, "transport space is not enough");
+ ret = -ENOMEM;
+ goto end_request;
+ }
+
+ insert_padding(cbdq, command_size);
+
+ cbd_req->req_tid = ++cbdq->req_tid;
+ queue_req_se_init(cbd_req);
+ cbdt_flush_range(cbdq->cbd_blkdev->cbdt, cbd_req->se, sizeof(struct cbd_se));
+
+ if (!cbd_req_nodata(cbd_req)) {
+ queue_req_data_init(cbd_req);
+ }
+
+ queue_delayed_work(cbdq->task_wq, &cbdq->complete_work, 0);
+
+ CBDC_UPDATE_CMDR_HEAD(cbdq->channel_info->cmd_head,
+ cbd_get_cmd_size(cbd_req),
+ cbdq->channel_info->cmdr_size);
+ cbdc_flush_ctrl(&cbdq->channel);
+ spin_unlock(&cbdq->channel.cmdr_lock);
+
+ return;
+
+end_request:
+ if (ret == -ENOMEM || ret == -EBUSY)
+ blk_mq_requeue_request(cbd_req->req, true);
+ else
+ blk_mq_end_request(cbd_req->req, errno_to_blk_status(ret));
+
+ return;
+}
+
+static void cbd_req_release(struct cbd_request *cbd_req)
+{
+ return;
+}
+
+static void advance_cmd_ring(struct cbd_queue *cbdq)
+{
+ struct cbd_se *se;
+again:
+ se = get_oldest_se(cbdq);
+ if (!se)
+ goto out;
+
+ if (cbd_se_hdr_flags_test(se, CBD_SE_HDR_DONE)) {
+ CBDC_UPDATE_CMDR_TAIL(cbdq->channel_info->cmd_tail,
+ cbd_se_hdr_get_len(se->header.len_op),
+ cbdq->channel_info->cmdr_size);
+ cbdc_flush_ctrl(&cbdq->channel);
+ goto again;
+ }
+out:
+ return;
+}
+
+static bool __advance_data_tail(struct cbd_queue *cbdq, u32 data_off, u32 data_len)
+{
+ if (data_off == cbdq->channel.data_tail) {
+ cbdq->released_extents[data_off / 4096] = 0;
+ cbdq->channel.data_tail += data_len;
+ if (cbdq->channel.data_tail >= cbdq->channel.data_size) {
+ cbdq->channel.data_tail %= cbdq->channel.data_size;
+ }
+ return true;
+ }
+
+ return false;
+}
+
+static void advance_data_tail(struct cbd_queue *cbdq, u32 data_off, u32 data_len)
+{
+ cbdq->released_extents[data_off / 4096] = data_len;
+
+ while (__advance_data_tail(cbdq, data_off, data_len)) {
+ data_off += data_len;
+ data_len = cbdq->released_extents[data_off / 4096];
+ if (!data_len) {
+ break;
+ }
+ }
+}
+
+static inline void complete_inflight_req(struct cbd_queue *cbdq, struct cbd_request *cbd_req, int ret)
+{
+ u32 data_off, data_len;
+ bool advance_data = false;
+
+ spin_lock(&cbdq->inflight_reqs_lock);
+ list_del_init(&cbd_req->inflight_reqs_node);
+ spin_unlock(&cbdq->inflight_reqs_lock);
+
+ cbd_se_hdr_flags_set(cbd_req->se, CBD_SE_HDR_DONE);
+ data_off = cbd_req->data_off;
+ data_len = cbd_req->data_len;
+ advance_data = (!cbd_req_nodata(cbd_req));
+
+ blk_mq_end_request(cbd_req->req, errno_to_blk_status(ret));
+
+ cbd_req_release(cbd_req);
+
+ spin_lock(&cbdq->channel.cmdr_lock);
+ advance_cmd_ring(cbdq);
+ if (advance_data)
+ advance_data_tail(cbdq, data_off, round_up(data_len, PAGE_SIZE));
+ spin_unlock(&cbdq->channel.cmdr_lock);
+}
+
+static struct cbd_request *fetch_inflight_req(struct cbd_queue *cbdq, u64 req_tid)
+{
+ struct cbd_request *req;
+ bool found = false;
+
+ list_for_each_entry(req, &cbdq->inflight_reqs, inflight_reqs_node) {
+ if (req->req_tid == req_tid) {
+ list_del_init(&req->inflight_reqs_node);
+ found = true;
+ break;
+ }
+ }
+
+ if (found)
+ return req;
+
+ return NULL;
+}
+
+static void copy_data_from_cbdteq(struct cbd_request *cbd_req)
+{
+ struct bio *bio = cbd_req->req->bio;
+ struct cbd_queue *cbdq = cbd_req->cbdq;
+
+ cbdc_copy_to_bio(&cbdq->channel, cbd_req->data_off, cbd_req->data_len, bio);
+
+ return;
+}
+
+static void complete_work_fn(struct work_struct *work)
+{
+ struct cbd_queue *cbdq = container_of(work, struct cbd_queue, complete_work.work);
+ struct cbd_ce *ce;
+ struct cbd_request *cbd_req;
+
+again:
+ /* compr_head would be updated by backend handler */
+ cbdc_flush_ctrl(&cbdq->channel);
+
+ spin_lock(&cbdq->channel.compr_lock);
+ ce = get_complete_entry(cbdq);
+ if (!ce) {
+ spin_unlock(&cbdq->channel.compr_lock);
+ if (cbdwc_need_retry(&cbdq->complete_worker_cfg)) {
+ goto again;
+ }
+
+ spin_lock(&cbdq->inflight_reqs_lock);
+ if (list_empty(&cbdq->inflight_reqs)) {
+ spin_unlock(&cbdq->inflight_reqs_lock);
+ cbdwc_init(&cbdq->complete_worker_cfg);
+ return;
+ }
+ spin_unlock(&cbdq->inflight_reqs_lock);
+
+ cbdwc_miss(&cbdq->complete_worker_cfg);
+
+ queue_delayed_work(cbdq->task_wq, &cbdq->complete_work, 0);
+ return;
+ }
+ cbdwc_hit(&cbdq->complete_worker_cfg);
+ CBDC_UPDATE_COMPR_TAIL(cbdq->channel_info->compr_tail,
+ sizeof(struct cbd_ce),
+ cbdq->channel_info->compr_size);
+ cbdc_flush_ctrl(&cbdq->channel);
+ spin_unlock(&cbdq->channel.compr_lock);
+
+ spin_lock(&cbdq->inflight_reqs_lock);
+ /* flush to ensure the content of ce is uptodate */
+ cbdt_flush_range(cbdq->cbd_blkdev->cbdt, ce, sizeof(*ce));
+ cbd_req = fetch_inflight_req(cbdq, ce->priv_data);
+ spin_unlock(&cbdq->inflight_reqs_lock);
+ if (!cbd_req) {
+ goto again;
+ }
+
+ if (req_op(cbd_req->req) == REQ_OP_READ) {
+ spin_lock(&cbdq->channel.cmdr_lock);
+ copy_data_from_cbdteq(cbd_req);
+ spin_unlock(&cbdq->channel.cmdr_lock);
+ }
+
+ complete_inflight_req(cbdq, cbd_req, ce->result);
+
+ goto again;
+}
+
+static blk_status_t cbd_queue_rq(struct blk_mq_hw_ctx *hctx,
+ const struct blk_mq_queue_data *bd)
+{
+ struct request *req = bd->rq;
+ struct cbd_queue *cbdq = hctx->driver_data;
+ struct cbd_request *cbd_req = blk_mq_rq_to_pdu(bd->rq);
+
+ memset(cbd_req, 0, sizeof(struct cbd_request));
+ INIT_LIST_HEAD(&cbd_req->inflight_reqs_node);
+
+ blk_mq_start_request(bd->rq);
+
+ switch (req_op(bd->rq)) {
+ case REQ_OP_FLUSH:
+ cbd_req_init(cbdq, CBD_OP_FLUSH, req);
+ break;
+ case REQ_OP_DISCARD:
+ cbd_req_init(cbdq, CBD_OP_DISCARD, req);
+ break;
+ case REQ_OP_WRITE_ZEROES:
+ cbd_req_init(cbdq, CBD_OP_WRITE_ZEROS, req);
+ break;
+ case REQ_OP_WRITE:
+ cbd_req_init(cbdq, CBD_OP_WRITE, req);
+ break;
+ case REQ_OP_READ:
+ cbd_req_init(cbdq, CBD_OP_READ, req);
+ break;
+ default:
+ return BLK_STS_IOERR;
+ }
+
+ cbd_queue_fn(cbd_req);
+
+ return BLK_STS_OK;
+}
+
+static int cbd_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
+ unsigned int hctx_idx)
+{
+ struct cbd_blkdev *cbd_blkdev = driver_data;
+ struct cbd_queue *cbdq;
+
+ cbdq = &cbd_blkdev->queues[hctx_idx];
+ hctx->driver_data = cbdq;
+
+ return 0;
+}
+
+const struct blk_mq_ops cbd_mq_ops = {
+ .queue_rq = cbd_queue_rq,
+ .init_hctx = cbd_init_hctx,
+};
+
+static int cbd_queue_channel_init(struct cbd_queue *cbdq, u32 channel_id)
+{
+ struct cbd_blkdev *cbd_blkdev = cbdq->cbd_blkdev;
+ struct cbd_transport *cbdt = cbd_blkdev->cbdt;
+
+ cbdq->channel_id = channel_id;
+ cbd_channel_init(&cbdq->channel, cbdt, channel_id);
+ cbdq->channel_info = cbdq->channel.channel_info;
+
+ cbdq->channel.data_head = cbdq->channel.data_tail = 0;
+
+ /* Initialise the channel_info of the ring buffer */
+ cbdq->channel_info->cmdr_off = CBDC_CMDR_OFF;
+ cbdq->channel_info->cmdr_size = CBDC_CMDR_SIZE;
+ cbdq->channel_info->compr_off = CBDC_COMPR_OFF;
+ cbdq->channel_info->compr_size = CBDC_COMPR_SIZE;
+
+ cbdq->channel_info->backend_id = cbd_blkdev->backend_id;
+ cbdq->channel_info->blkdev_id = cbd_blkdev->blkdev_id;
+ cbdq->channel_info->blkdev_state = cbdc_blkdev_state_running;
+ cbdq->channel_info->state = cbd_channel_state_running;
+
+ cbdc_flush_ctrl(&cbdq->channel);
+
+ return 0;
+}
+
+int cbd_queue_start(struct cbd_queue *cbdq)
+{
+ struct cbd_transport *cbdt = cbdq->cbd_blkdev->cbdt;
+ u32 channel_id;
+ int ret;
+
+ ret = cbdt_get_empty_channel_id(cbdt, &channel_id);
+ if (ret < 0) {
+ cbdt_err(cbdt, "failed find available channel_id.\n");
+ goto err;
+ }
+
+ ret = cbd_queue_channel_init(cbdq, channel_id);
+ if (ret) {
+ cbd_queue_err(cbdq, "failed to init dev channel_info: %d.", ret);
+ goto err;
+ }
+
+ INIT_LIST_HEAD(&cbdq->inflight_reqs);
+ spin_lock_init(&cbdq->inflight_reqs_lock);
+ cbdq->req_tid = 0;
+ INIT_DELAYED_WORK(&cbdq->complete_work, complete_work_fn);
+ cbdwc_init(&cbdq->complete_worker_cfg);
+
+ cbdq->released_extents = kmalloc(sizeof(u32) * (CBDC_DATA_SIZE >> PAGE_SHIFT), GFP_KERNEL);
