new file mode 100644
@@ -0,0 +1,551 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include "cbd_internal.h"
+#include "cbd_blkdev.h"
+
+static ssize_t backend_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_blkdev_device *blkdev_dev;
+ struct cbd_blkdev_info *blkdev_info;
+
+ blkdev_dev = container_of(dev, struct cbd_blkdev_device, dev);
+ blkdev_info = cbdt_blkdev_info_read(blkdev_dev->cbdt, blkdev_dev->id);
+ if (!blkdev_info)
+ return 0;
+
+ if (blkdev_info->state == CBD_BLKDEV_STATE_NONE)
+ return 0;
+
+ return sprintf(buf, "%u\n", blkdev_info->backend_id);
+}
+static DEVICE_ATTR_ADMIN_RO(backend_id);
+
+static ssize_t host_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_blkdev_device *blkdev_dev;
+ struct cbd_blkdev_info *blkdev_info;
+
+ blkdev_dev = container_of(dev, struct cbd_blkdev_device, dev);
+ blkdev_info = cbdt_blkdev_info_read(blkdev_dev->cbdt, blkdev_dev->id);
+ if (!blkdev_info)
+ return 0;
+
+ if (blkdev_info->state == CBD_BLKDEV_STATE_NONE)
+ return 0;
+
+ return sprintf(buf, "%u\n", blkdev_info->host_id);
+}
+static DEVICE_ATTR_ADMIN_RO(host_id);
+
+static ssize_t mapped_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_blkdev_device *blkdev_dev;
+ struct cbd_blkdev_info *blkdev_info;
+
+ blkdev_dev = container_of(dev, struct cbd_blkdev_device, dev);
+ blkdev_info = cbdt_blkdev_info_read(blkdev_dev->cbdt, blkdev_dev->id);
+ if (!blkdev_info)
+ return 0;
+
+ if (blkdev_info->state == CBD_BLKDEV_STATE_NONE)
+ return 0;
+
+ return sprintf(buf, "%u\n", blkdev_info->mapped_id);
+}
+static DEVICE_ATTR_ADMIN_RO(mapped_id);
+
+static void blkdev_info_write(struct cbd_blkdev *blkdev)
+{
+ mutex_lock(&blkdev->info_lock);
+ blkdev->blkdev_info.alive_ts = ktime_get_real();
+ cbdt_blkdev_info_write(blkdev->cbdt, &blkdev->blkdev_info,
+ sizeof(struct cbd_blkdev_info),
+ blkdev->blkdev_id);
+ mutex_unlock(&blkdev->info_lock);
+}
+
+static void cbd_blkdev_hb(struct cbd_blkdev *blkdev)
+{
+ blkdev_info_write(blkdev);
+}
+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)
+{
+}
+
+const struct device_type cbd_blkdev_type = {
+ .name = "cbd_blkdev",
+ .groups = cbd_blkdev_attr_groups,
+ .release = cbd_blkdev_release,
+};
+
+const 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)
+{
+ struct cbd_blkdev *cbd_blkdev = disk->private_data;
+
+ mutex_lock(&cbd_blkdev->lock);
+ cbd_blkdev->open_count++;
+ mutex_unlock(&cbd_blkdev->lock);
+
+ return 0;
+}
+
+static void cbd_release(struct gendisk *disk)
+{
+ struct cbd_blkdev *cbd_blkdev = disk->private_data;
+
+ mutex_lock(&cbd_blkdev->lock);
+ cbd_blkdev->open_count--;
+ mutex_unlock(&cbd_blkdev->lock);
+}
+
+static const struct block_device_operations cbd_bd_ops = {
+ .owner = THIS_MODULE,
+ .open = cbd_open,
+ .release = cbd_release,
+};
+
+/**
+ * cbd_blkdev_destroy_queues - Stop and free the queues associated with the block device
+ * @cbd_blkdev: Pointer to the block device structure
+ *
+ * Note: The cbd_queue_stop function checks the state of each queue before attempting
+ * to stop it. If a queue's state is not running, it will return immediately,
+ * ensuring that only running queues are affected by this operation.
+ */
+static void cbd_blkdev_destroy_queues(struct cbd_blkdev *cbd_blkdev)
+{
+ int i;
+
+ /* Stop each queue associated with the block device */
+ for (i = 0; i < cbd_blkdev->num_queues; i++)
+ cbd_queue_stop(&cbd_blkdev->queues[i]);
+
+ /* Free the memory allocated for the queues */
+ kfree(cbd_blkdev->queues);
+}
+
+/**
+ * cbd_blkdev_create_queues - Create and initialize queues for the block device
+ * @cbd_blkdev: Pointer to the block device structure
+ * @channels: Array of channel identifiers for each queue
+ *
+ * Note: The cbd_blkdev_destroy_queues function checks the state of each queue.
+ * Only queues that have been started will be stopped in the error path.
+ * Therefore, any queues that were not started will not be affected.
+ */
+static int cbd_blkdev_create_queues(struct cbd_blkdev *cbd_blkdev, u32 *channels)
+{
+ 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, channels[i]);
+ if (ret)
+ goto err;
+ }
+
+ return 0;
+
+err:
+ cbd_blkdev_destroy_queues(cbd_blkdev);
+ return ret;
+}
+
+static int disk_start(struct cbd_blkdev *cbd_blkdev)
+{
+ struct gendisk *disk;
+ struct queue_limits lim = {
+ .max_hw_sectors = BIO_MAX_VECS * PAGE_SECTORS,
+ .io_min = 4096,
+ .io_opt = 4096,
+ .max_segments = USHRT_MAX,
+ .max_segment_size = UINT_MAX,
+ .discard_granularity = 0,
+ .max_hw_discard_sectors = 0,
+ .max_write_zeroes_sectors = 0
+ };
+ int ret;
+
+ 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) {
+ cbd_blk_err(cbd_blkdev, "failed to alloc tag set %d", ret);
+ goto err;
+ }
+
+ disk = blk_mq_alloc_disk(&cbd_blkdev->tag_set, &lim, cbd_blkdev);
+ if (IS_ERR(disk)) {
+ ret = PTR_ERR(disk);
+ cbd_blk_err(cbd_blkdev, "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;
+
+ cbd_blkdev->disk = disk;
+ cbdt_add_blkdev(cbd_blkdev->cbdt, cbd_blkdev);
+ cbd_blkdev->blkdev_info.mapped_id = cbd_blkdev->blkdev_id;
+
+ set_capacity(cbd_blkdev->disk, cbd_blkdev->dev_size);
+ set_disk_ro(cbd_blkdev->disk, false);
+
+ /* Register the disk with the system */
+ ret = add_disk(cbd_blkdev->disk);
+ if (ret)
+ goto put_disk;
+
+ /* Create a symlink to the block device */
+ ret = sysfs_create_link(&disk_to_dev(cbd_blkdev->disk)->kobj,
+ &cbd_blkdev->blkdev_dev->dev.kobj, "cbd_blkdev");
+ if (ret)
+ goto del_disk;
+
+ 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;
+}
+
+static void disk_stop(struct cbd_blkdev *cbd_blkdev)
+{
+ sysfs_remove_link(&disk_to_dev(cbd_blkdev->disk)->kobj, "cbd_blkdev");
+ del_gendisk(cbd_blkdev->disk);
+ put_disk(cbd_blkdev->disk);
+ blk_mq_free_tag_set(&cbd_blkdev->tag_set);
+}
+
+/**
+ * If *queues is 0, it defaults to backend_info->n_handlers, matching the backend's
+ * handler capacity.
+ */
+static int blkdev_start_validate(struct cbd_transport *cbdt, struct cbd_backend_info *backend_info,
+ u32 backend_id, u32 *queues)
+{
+ struct cbd_blkdev_info *blkdev_info;
+ u32 backend_blkdevs = 0;
+ u32 i;
+
+ if (!backend_info || !cbd_backend_info_is_alive(backend_info)) {
+ cbdt_err(cbdt, "backend %u is not alive\n", backend_id);
+ return -EINVAL;
+ }
+
+ cbd_for_each_blkdev_info(cbdt, i, blkdev_info) {
+ if (!blkdev_info || blkdev_info->state != CBD_BLKDEV_STATE_RUNNING)
+ continue;
+
+ if (blkdev_info->backend_id == backend_id)
+ backend_blkdevs++;
+ }
+
+ if (backend_blkdevs >= CBDB_BLKDEV_COUNT_MAX) {
+ cbdt_err(cbdt, "too many(%u) blkdevs connected to backend %u.\n", backend_blkdevs, backend_id);
+ return -EBUSY;
+ }
+
+ if (*queues == 0)
+ *queues = backend_info->n_handlers;
+
+ if (*queues > backend_info->n_handlers) {
+ cbdt_err(cbdt, "invalid queues: %u, larger than backend handlers: %u\n",
+ *queues, backend_info->n_handlers);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static struct cbd_blkdev *blkdev_alloc(struct cbd_transport *cbdt)
+{
+ struct cbd_blkdev *cbd_blkdev;
+ int ret;
+
+ cbd_blkdev = kzalloc(sizeof(struct cbd_blkdev), GFP_KERNEL);
+ if (!cbd_blkdev)
+ return NULL;
+
+ cbd_blkdev->cbdt = cbdt;
+ mutex_init(&cbd_blkdev->lock);
+ mutex_init(&cbd_blkdev->info_lock);
+ INIT_LIST_HEAD(&cbd_blkdev->node);
+ INIT_DELAYED_WORK(&cbd_blkdev->hb_work, blkdev_hb_workfn);
+
+ 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;
+ }
+
+ cbd_blkdev->task_wq = alloc_workqueue("cbdt%d-d%u", WQ_UNBOUND | WQ_MEM_RECLAIM,
+ 0, cbdt->id, cbd_blkdev->mapped_id);
+ if (!cbd_blkdev->task_wq) {
+ ret = -ENOMEM;
+ goto ida_remove;
+ }
+
+ return cbd_blkdev;
+
+ida_remove:
+ ida_simple_remove(&cbd_mapped_id_ida, cbd_blkdev->mapped_id);
+blkdev_free:
+ kfree(cbd_blkdev);
+
+ return NULL;
+}
+
+static void blkdev_free(struct cbd_blkdev *cbd_blkdev)
+{
+ drain_workqueue(cbd_blkdev->task_wq);
+ destroy_workqueue(cbd_blkdev->task_wq);
+ ida_simple_remove(&cbd_mapped_id_ida, cbd_blkdev->mapped_id);
+ kfree(cbd_blkdev);
+}
+
+static int blkdev_cache_init(struct cbd_blkdev *cbd_blkdev)
+{
+ struct cbd_transport *cbdt = cbd_blkdev->cbdt;
+ struct cbd_cache_opts cache_opts = { 0 };
+
+ cache_opts.cache_info = &cbd_blkdev->cache_info;
+ cache_opts.cache_id = cbd_blkdev->backend_id;
+ cache_opts.owner = NULL;
+ cache_opts.new_cache = false;
+ cache_opts.start_writeback = false;
+ cache_opts.start_gc = true;
+ cache_opts.init_req_keys = true;
+ cache_opts.dev_size = cbd_blkdev->dev_size;
+ cache_opts.n_paral = cbd_blkdev->num_queues;
+
+ cbd_blkdev->cbd_cache = cbd_cache_alloc(cbdt, &cache_opts);
+ if (!cbd_blkdev->cbd_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void blkdev_cache_destroy(struct cbd_blkdev *cbd_blkdev)
+{
+ if (cbd_blkdev->cbd_cache)
+ cbd_cache_destroy(cbd_blkdev->cbd_cache);
+}
+
+static int blkdev_init(struct cbd_blkdev *cbd_blkdev, struct cbd_backend_info *backend_info,
+ u32 backend_id, u32 queues)
+{
+ struct cbd_transport *cbdt = cbd_blkdev->cbdt;
+ int ret;
+
+ cbd_blkdev->backend_id = backend_id;
+ cbd_blkdev->num_queues = queues;
+ cbd_blkdev->dev_size = backend_info->dev_size;
+ cbd_blkdev->blkdev_dev = &cbdt->cbd_blkdevs_dev->blkdev_devs[cbd_blkdev->blkdev_id];
+
+ /* Get the backend if it is hosted on the same machine */
+ if (backend_info->host_id == cbdt->host->host_id)
+ cbd_blkdev->backend = cbdt_get_backend(cbdt, backend_id);
+
+ cbd_blkdev->blkdev_info.backend_id = backend_id;
+ cbd_blkdev->blkdev_info.host_id = cbdt->host->host_id;
+ cbd_blkdev->blkdev_info.state = CBD_BLKDEV_STATE_RUNNING;
+
+ ret = cbd_blkdev_create_queues(cbd_blkdev, backend_info->handler_channels);
+ if (ret < 0)
+ goto err;
+
+ if (cbd_backend_cache_on(backend_info)) {
+ ret = blkdev_cache_init(cbd_blkdev);
+ if (ret)
+ goto destroy_queues;
+ }
+
+ return 0;
+destroy_queues:
+ cbd_blkdev_destroy_queues(cbd_blkdev);
+err:
+ return ret;
+}
+
+static void blkdev_destroy(struct cbd_blkdev *cbd_blkdev)
+{
+ cancel_delayed_work_sync(&cbd_blkdev->hb_work);
+ blkdev_cache_destroy(cbd_blkdev);
+ cbd_blkdev_destroy_queues(cbd_blkdev);
+}
+
+int cbd_blkdev_start(struct cbd_transport *cbdt, u32 backend_id, u32 queues)
+{
+ struct cbd_blkdev *cbd_blkdev;
+ struct cbd_backend_info *backend_info;
+ int ret;
+
+ backend_info = cbdt_backend_info_read(cbdt, backend_id);
+ if (!backend_info) {
+ cbdt_err(cbdt, "cant read backend info for backend%u.\n", backend_id);
+ return -ENOENT;
+ }
+
+ ret = blkdev_start_validate(cbdt, backend_info, backend_id, &queues);
+ if (ret)
+ return ret;
+
+ cbd_blkdev = blkdev_alloc(cbdt);
+ if (!cbd_blkdev)
+ return -ENOMEM;
+
+ ret = blkdev_init(cbd_blkdev, backend_info, backend_id, queues);
+ if (ret)
+ goto blkdev_free;
+
+ ret = disk_start(cbd_blkdev);
+ if (ret < 0)
+ goto blkdev_destroy;
+
+ blkdev_info_write(cbd_blkdev);
+ queue_delayed_work(cbd_wq, &cbd_blkdev->hb_work, 0);
+
+ return 0;
+
+blkdev_destroy:
+ blkdev_destroy(cbd_blkdev);
+blkdev_free:
+ blkdev_free(cbd_blkdev);
+ return ret;
+}
+
+int cbd_blkdev_stop(struct cbd_transport *cbdt, u32 devid)
+{
+ struct cbd_blkdev *cbd_blkdev;
+
+ cbd_blkdev = cbdt_get_blkdev(cbdt, devid);
+ if (!cbd_blkdev)
+ return -EINVAL;
+
+ mutex_lock(&cbd_blkdev->lock);
+ if (cbd_blkdev->open_count > 0) {
+ mutex_unlock(&cbd_blkdev->lock);
+ return -EBUSY;
+ }
+
+ cbdt_del_blkdev(cbdt, cbd_blkdev);
+ mutex_unlock(&cbd_blkdev->lock);
+
+ disk_stop(cbd_blkdev);
+ blkdev_destroy(cbd_blkdev);
+ blkdev_free(cbd_blkdev);
+ cbdt_blkdev_info_clear(cbdt, devid);
+
+ return 0;
+}
+
+int cbd_blkdev_clear(struct cbd_transport *cbdt, u32 devid)
+{
+ struct cbd_blkdev_info *blkdev_info;
+
+ blkdev_info = cbdt_blkdev_info_read(cbdt, devid);
+ if (!blkdev_info) {
+ cbdt_err(cbdt, "all blkdev_info in blkdev_id: %u are corrupted.\n", devid);
+ return -EINVAL;
+ }
+
+ if (cbd_blkdev_info_is_alive(blkdev_info)) {
+ cbdt_err(cbdt, "blkdev %u is still alive\n", devid);
+ return -EBUSY;
+ }
+
+ if (blkdev_info->state == CBD_BLKDEV_STATE_NONE)
+ return 0;
+
+ cbdt_blkdev_info_clear(cbdt, devid);
+
+ 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");
+}
new file mode 100644
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _CBD_BLKDEV_H
+#define _CBD_BLKDEV_H
+
+#include <linux/blk-mq.h>
+
+#include "cbd_internal.h"
+#include "cbd_transport.h"
+#include "cbd_channel.h"
+#include "cbd_cache/cbd_cache.h"
+#include "cbd_handler.h"
+#include "cbd_backend.h"
+#include "cbd_queue.h"
+
+#define cbd_blk_err(dev, fmt, ...) \
+ cbdt_err(dev->cbdt, "cbd%d: " fmt, \
+ dev->mapped_id, ##__VA_ARGS__)
+#define cbd_blk_info(dev, fmt, ...) \
+ cbdt_info(dev->cbdt, "cbd%d: " fmt, \
+ dev->mapped_id, ##__VA_ARGS__)
+#define cbd_blk_debug(dev, fmt, ...) \
+ cbdt_debug(dev->cbdt, "cbd%d: " fmt, \
+ dev->mapped_id, ##__VA_ARGS__)
+
+/* cbd_blkdev */
+CBD_DEVICE(blkdev);
+
+#define CBD_BLKDEV_STATE_NONE 0
+#define CBD_BLKDEV_STATE_RUNNING 1
+
+struct cbd_blkdev_info {
+ struct cbd_meta_header meta_header;
+ u8 state;
+ u64 alive_ts;
+ u32 backend_id;
+ u32 host_id;
+ u32 mapped_id;
+};
+
+struct cbd_blkdev {
+ u32 blkdev_id; /* index in transport blkdev area */
+ u32 backend_id;
+ int mapped_id; /* id in block device such as: /dev/cbd0 */
+
+ struct cbd_backend *backend; /* reference to backend if blkdev and backend on the same host */
+
+ int major; /* blkdev assigned major */
+ int minor;
+ struct gendisk *disk; /* blkdev's gendisk and rq */
+
+ struct mutex lock;
+ unsigned long open_count; /* protected by lock */
+
+ struct list_head node;
+ struct delayed_work hb_work; /* heartbeat work */
+
+ /* Block layer tags. */
+ struct blk_mq_tag_set tag_set;
+
+ uint32_t num_queues;
+ struct cbd_queue *queues;
+
+ u64 dev_size;
+
+ struct workqueue_struct *task_wq;
+
+ struct cbd_blkdev_device *blkdev_dev;
+ struct cbd_blkdev_info blkdev_info;
+ struct mutex info_lock;
+
+ struct cbd_transport *cbdt;
+
+ struct cbd_cache_info cache_info;
+ struct cbd_cache *cbd_cache;
+};
+
+int cbd_blkdev_init(void);
+void cbd_blkdev_exit(void);
+int cbd_blkdev_start(struct cbd_transport *cbdt, u32 backend_id, u32 queues);
+int cbd_blkdev_stop(struct cbd_transport *cbdt, u32 devid);
+int cbd_blkdev_clear(struct cbd_transport *cbdt, u32 devid);
+bool cbd_blkdev_info_is_alive(struct cbd_blkdev_info *info);
+
+extern struct workqueue_struct *cbd_wq;
+
+#define cbd_for_each_blkdev_info(cbdt, i, blkdev_info) \
+ for (i = 0; \
+ i < cbdt->transport_info.blkdev_num && \
+ (blkdev_info = cbdt_blkdev_info_read(cbdt, i)); \
+ i++)
+
+#endif /* _CBD_BLKDEV_H */
new file mode 100644
@@ -0,0 +1,516 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "cbd_queue.h"
+
+/**
+ * end_req - Finalize a CBD request and handle its completion.
+ * @ref: Pointer to the kref structure that manages the reference count of the CBD request.
+ *
+ * This function is called when the reference count of the cbd_request reaches zero. It
+ * contains two key operations:
+ *
+ * (1) If the end_req callback is set in the cbd_request, this callback will be invoked.
+ * This allows different cbd_requests to perform specific operations upon completion.
+ * For example, in the case of a backend request sent in the cache miss reading, it may require
+ * cache-related operations, such as storing data retrieved during a miss read.
+ *
+ * (2) If cbd_req->req is not NULL, it indicates that this cbd_request corresponds to a
+ * block layer request. The function will finalize the block layer request accordingly.
+ */
+static void end_req(struct kref *ref)
+{
+ struct cbd_request *cbd_req = container_of(ref, struct cbd_request, ref);
+ struct request *req = cbd_req->req;
+ int ret = cbd_req->ret;
+
+ /* Call the end_req callback if it is set */
+ if (cbd_req->end_req)
+ cbd_req->end_req(cbd_req, cbd_req->priv_data);
+
+ if (req) {
+ /* Complete the block layer request based on the return status */
+ if (ret == -ENOMEM || ret == -EBUSY)
+ blk_mq_requeue_request(req, true);
+ else
+ blk_mq_end_request(req, errno_to_blk_status(ret));
+ }
+}
+
+void cbd_req_get(struct cbd_request *cbd_req)
+{
+ kref_get(&cbd_req->ref);
+}
+
+/**
+ * This function decreases the reference count of the specified cbd_request. If the
+ * reference count reaches zero, the end_req function is called to finalize the request.
+ * Additionally, if the cbd_request has a parent and if the current request is being
+ * finalized (i.e., the reference count reaches zero), the parent request will also
+ * be put, potentially propagating the return status up the hierarchy.
+ */
+void cbd_req_put(struct cbd_request *cbd_req, int ret)
+{
+ struct cbd_request *parent = cbd_req->parent;
+
+ /* Set the return status if it is not already set */
+ if (ret && !cbd_req->ret)
+ cbd_req->ret = ret;
+
+ /* Decrease the reference count and finalize the request if it reaches zero */
+ if (kref_put(&cbd_req->ref, end_req) && parent)
+ cbd_req_put(parent, ret);
+}
+
+/**
+ * When a submission entry is completed, it is marked with the CBD_SE_FLAGS_DONE flag.
+ * If the entry is the oldest one in the submission queue, the tail of the submission ring
+ * can be advanced. If it is not the oldest, the function will wait until all previous
+ * entries have been completed before advancing the tail.
+ */
+static void advance_subm_ring(struct cbd_queue *cbdq)
+{
+ struct cbd_se *se;
+again:
+ se = get_oldest_se(cbdq);
+ if (!se)
+ goto out;
+
+ if (cbd_se_flags_test(se, CBD_SE_FLAGS_DONE)) {
+ cbdc_submr_tail_advance(&cbdq->channel, sizeof(struct cbd_se));
+ goto again;
+ }
+out:
+ return;
+}
+
+/**
+ * This function checks if the specified data offset corresponds to the current
+ * data tail. If it does, the function releases the corresponding extent by
+ * setting the value in the released_extents array to zero and advances the
+ * data tail by the specified length. The data tail is wrapped around if it
+ * exceeds the channel's data size.
+ */
+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 / PAGE_SIZE] = 0;
+ cbdq->channel.data_tail += data_len;
+ cbdq->channel.data_tail %= cbdq->channel.data_size;
+ return true;
+ }
+
+ return false;
+}
+
+/**
+ * This function attempts to advance the data tail in the CBD queue by processing
+ * the released extents. It first normalizes the data offset with respect to the
+ * channel's data size. It then marks the released extent and attempts to advance
+ * the data tail by repeatedly checking if the next extent can be released.
+ */
+static void advance_data_tail(struct cbd_queue *cbdq, u32 data_off, u32 data_len)
+{
+ data_off %= cbdq->channel.data_size;
+ cbdq->released_extents[data_off / PAGE_SIZE] = data_len;
+
+ while (__advance_data_tail(cbdq, data_off, data_len)) {
+ data_off += data_len;
+ data_off %= cbdq->channel.data_size;
+ data_len = cbdq->released_extents[data_off / PAGE_SIZE];
+ /*
+ * if data_len in released_extents is zero, means this extent is not released,
+ * break and wait it to be released.
+ */
+ if (!data_len)
+ break;
+ }
+}
+
+void cbd_queue_advance(struct cbd_queue *cbdq, struct cbd_request *cbd_req)
+{
+ spin_lock(&cbdq->channel.submr_lock);
+ advance_subm_ring(cbdq);
+
+ if (!cbd_req_nodata(cbd_req) && cbd_req->data_len)
+ advance_data_tail(cbdq, cbd_req->data_off, round_up(cbd_req->data_len, PAGE_SIZE));
+ spin_unlock(&cbdq->channel.submr_lock);
+}
+
+static int queue_ce_verify(struct cbd_queue *cbdq, struct cbd_request *cbd_req,
+ struct cbd_ce *ce)
+{
+#ifdef CONFIG_CBD_CHANNEL_CRC
+ if (ce->ce_crc != cbd_ce_crc(ce)) {
+ cbd_queue_err(cbdq, "ce crc bad 0x%x != 0x%x(expected)",
+ cbd_ce_crc(ce), ce->ce_crc);
+ return -EIO;
+ }
+#endif
+
+#ifdef CONFIG_CBD_CHANNEL_DATA_CRC
+ if (cbd_req->op == CBD_OP_READ &&
+ ce->data_crc != cbd_channel_crc(&cbdq->channel,
+ cbd_req->data_off,
+ cbd_req->data_len)) {
+ cbd_queue_err(cbdq, "ce data_crc bad 0x%x != 0x%x(expected)",
+ cbd_channel_crc(&cbdq->channel,
+ cbd_req->data_off,
+ cbd_req->data_len),
+ ce->data_crc);
+ return -EIO;
+ }
+#endif
+ return 0;
+}
+
+static int complete_miss(struct cbd_queue *cbdq)
+{
+ if (cbdwc_need_retry(&cbdq->complete_worker_cfg))
+ return -EAGAIN;
+
+ if (inflight_reqs_empty(cbdq)) {
+ cbdwc_init(&cbdq->complete_worker_cfg);
+ goto out;
+ }
+
+ cbdwc_miss(&cbdq->complete_worker_cfg);
+
+ cpu_relax();
+ queue_delayed_work(cbdq->cbd_blkdev->task_wq, &cbdq->complete_work, 0);
+out:
+ return 0;
+}
+
+static void complete_work_fn(struct work_struct *work)
+{
+ struct cbd_queue *cbdq = container_of(work, struct cbd_queue, complete_work.work);
+ struct cbd_request *cbd_req;
+ struct cbd_ce *ce;
+ int ret;
+again:
+ /* compr_head would be updated by backend handler */
+ spin_lock(&cbdq->channel.compr_lock);
+ ce = get_complete_entry(cbdq);
+ spin_unlock(&cbdq->channel.compr_lock);
+ if (!ce)
+ goto miss;
+
+ cbd_req = find_inflight_req(cbdq, ce->req_tid);
+ if (!cbd_req) {
+ cbd_queue_err(cbdq, "inflight request not found: %llu.", ce->req_tid);
+ goto miss;
+ }
+
+ ret = queue_ce_verify(cbdq, cbd_req, ce);
+ if (ret)
+ goto miss;
+
+ cbdwc_hit(&cbdq->complete_worker_cfg);
+ cbdc_compr_tail_advance(&cbdq->channel, sizeof(struct cbd_ce));
+ complete_inflight_req(cbdq, cbd_req, ce->result);
+ goto again;
+miss:
+ ret = complete_miss(cbdq);
+ /* -EAGAIN means we need retry according to the complete_worker_cfg */
+ if (ret == -EAGAIN)
+ goto again;
+}
+
+static void cbd_req_init(struct cbd_queue *cbdq, u8 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;
+
+ if (!cbd_req_nodata(cbd_req))
+ cbd_req->data_len = blk_rq_bytes(rq);
+ else
+ cbd_req->data_len = 0;
+
+ cbd_req->bio = rq->bio;
+ cbd_req->off = (u64)blk_rq_pos(rq) << SECTOR_SHIFT;
+}
+
+static void queue_req_se_init(struct cbd_request *cbd_req)
+{
+ struct cbd_se *se;
+ u64 offset = cbd_req->off;
+ u32 length = cbd_req->data_len;
+
+ se = get_submit_entry(cbd_req->cbdq);
+ memset(se, 0, sizeof(struct cbd_se));
+
+ se->op = cbd_req->op;
+ se->req_tid = cbd_req->req_tid;
+ se->offset = offset;
+ se->len = length;
+
+ if (!cbd_req_nodata(cbd_req)) {
+ se->data_off = cbd_req->cbdq->channel.data_head;
+ se->data_len = length;
+ }
+ cbd_req->se = se;
+}
+
+static void cbd_req_crc_init(struct cbd_request *cbd_req)
+{
+#ifdef CONFIG_CBD_CHANNEL_DATA_CRC
+ struct cbd_queue *cbdq = cbd_req->cbdq;
+
+ if (cbd_req->op == CBD_OP_WRITE)
+ cbd_req->se->data_crc = cbd_channel_crc(&cbdq->channel,
+ cbd_req->data_off,
+ cbd_req->data_len);
+#endif
+
+#ifdef CONFIG_CBD_CHANNEL_CRC
+ cbd_req->se->se_crc = cbd_se_crc(cbd_req->se);
+#endif
+}
+
+static void queue_req_channel_init(struct cbd_request *cbd_req)
+{
+ struct cbd_queue *cbdq = cbd_req->cbdq;
+ struct bio *bio = cbd_req->bio;
+
+ cbd_req->req_tid = cbdq->req_tid++;
+ queue_req_se_init(cbd_req);
+
+ if (cbd_req_nodata(cbd_req))
+ goto crc_init;
+
+ cbd_req->data_off = cbdq->channel.data_head;
+ if (cbd_req->op == CBD_OP_WRITE)
+ cbdc_copy_from_bio(&cbdq->channel, cbd_req->data_off,
+ cbd_req->data_len, bio, cbd_req->bio_off);
+
+ cbdq->channel.data_head = round_up(cbdq->channel.data_head + cbd_req->data_len, PAGE_SIZE);
+ cbdq->channel.data_head %= cbdq->channel.data_size;
+crc_init:
+ cbd_req_crc_init(cbd_req);
+}
+
+int cbd_queue_req_to_backend(struct cbd_request *cbd_req)
+{
+ struct cbd_queue *cbdq = cbd_req->cbdq;
+ int ret;
+
+ spin_lock(&cbdq->channel.submr_lock);
+ /* Check if the submission ring is full or if there is enough data space */
+ if (submit_ring_full(cbdq) ||
+ !data_space_enough(cbdq, cbd_req)) {
+ spin_unlock(&cbdq->channel.submr_lock);
+ cbd_req->data_len = 0;
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ /* Get a reference before submission, it will be put in cbd_req completion */
+ cbd_req_get(cbd_req);
+
+ inflight_add_req(cbdq, cbd_req);
+ queue_req_channel_init(cbd_req);
+
+ cbdc_submr_head_advance(&cbdq->channel, sizeof(struct cbd_se));
+ spin_unlock(&cbdq->channel.submr_lock);
+
+ if (cbdq->cbd_blkdev->backend)
+ cbd_backend_notify(cbdq->cbd_blkdev->backend, cbdq->channel.seg_id);
+ queue_delayed_work(cbdq->cbd_blkdev->task_wq, &cbdq->complete_work, 0);
+
+ return 0;
+err:
+ return ret;
+}
+
+static void queue_req_end_req(struct cbd_request *cbd_req, void *priv_data)
+{
+ cbd_queue_advance(cbd_req->cbdq, cbd_req);
+}
+
+static void cbd_queue_req(struct cbd_queue *cbdq, struct cbd_request *cbd_req)
+{
+ int ret;
+
+ if (cbdq->cbd_blkdev->cbd_cache) {
+ ret = cbd_cache_handle_req(cbdq->cbd_blkdev->cbd_cache, cbd_req);
+ goto end;
+ }
+ cbd_req->end_req = queue_req_end_req;
+ ret = cbd_queue_req_to_backend(cbd_req);
+end:
+ cbd_req_put(cbd_req, ret);
+}
+
+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);
+ kref_init(&cbd_req->ref);
+ spin_lock_init(&cbd_req->lock);
+
+ 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_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_req(cbdq, 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,
+};
+
+#define CBDQ_RESET_CHANNEL_WAIT_INTERVAL (HZ / 10)
+#define CBDQ_RESET_CHANNEL_WAIT_COUNT 300
+
+/**
+ * queue_reset_channel - Sends a reset command to the management layer for a cbd_queue.
+ * @cbdq: Pointer to the cbd_queue structure to be reset.
+ *
+ * This function initiates a channel reset by sending a management command to the
+ * corresponding channel control structure. It waits for the reset operation to
+ * complete, polling the status and allowing for a timeout to avoid indefinite blocking.
+ *
+ * Returns 0 on success, or a negative error code on failure (e.g., -ETIMEDOUT).
+ */
+static int queue_reset_channel(struct cbd_queue *cbdq)
+{
+ u8 cmd_ret;
+ u16 count = 0;
+ int ret;
+
+ ret = cbdc_mgmt_cmd_op_send(cbdq->channel_ctrl, CBDC_MGMT_CMD_RESET);
+ if (ret) {
+ cbd_queue_err(cbdq, "send reset mgmt cmd error: %d\n", ret);
+ return ret;
+ }
+
+ if (cbdq->cbd_blkdev->backend)
+ cbd_backend_mgmt_notify(cbdq->cbd_blkdev->backend, cbdq->channel.seg_id);
+
+ while (true) {
+ if (cbdc_mgmt_completed(cbdq->channel_ctrl))
+ break;
+
+ if (count++ > CBDQ_RESET_CHANNEL_WAIT_COUNT) {
+ ret = -ETIMEDOUT;
+ goto err;
+ }
+ schedule_timeout_uninterruptible(CBDQ_RESET_CHANNEL_WAIT_INTERVAL);
+ }
+ cmd_ret = cbdc_mgmt_cmd_ret_get(cbdq->channel_ctrl);
+ return cbdc_mgmt_cmd_ret_to_errno(cmd_ret);
+err:
+ return ret;
+}
+
+static int 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;
+ struct cbd_channel_init_options init_opts = { 0 };
+ int ret;
+
+ init_opts.cbdt = cbdt;
+ init_opts.backend_id = cbdq->cbd_blkdev->backend_id;
+ init_opts.seg_id = channel_id;
+ init_opts.new_channel = false;
+ ret = cbd_channel_init(&cbdq->channel, &init_opts);
+ if (ret)
+ return ret;
+
+ cbdq->channel_ctrl = cbdq->channel.ctrl;
+ if (!cbd_blkdev->backend)
+ cbd_channel_flags_set_bit(cbdq->channel_ctrl, CBDC_FLAGS_POLLING);
+
+ ret = queue_reset_channel(cbdq);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int queue_init(struct cbd_queue *cbdq, u32 channel_id)
+{
+ int ret;
+
+ 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);
+
+ ret = queue_channel_init(cbdq, channel_id);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+int cbd_queue_start(struct cbd_queue *cbdq, u32 channel_id)
+{
+ int ret;
+
+ cbdq->released_extents = kzalloc(sizeof(u64) * (CBDC_DATA_SIZE >> PAGE_SHIFT),
+ GFP_KERNEL);
+ if (!cbdq->released_extents) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = queue_init(cbdq, channel_id);
+ if (ret)
+ goto free_extents;
+
+ atomic_set(&cbdq->state, cbd_queue_state_running);
+
+ return 0;
+
+free_extents:
+ kfree(cbdq->released_extents);
+out:
+ return ret;
+}
+
+void cbd_queue_stop(struct cbd_queue *cbdq)
+{
+ if (atomic_read(&cbdq->state) != cbd_queue_state_running)
+ return;
+
+ cancel_delayed_work_sync(&cbdq->complete_work);
+ kfree(cbdq->released_extents);
+}
new file mode 100644
@@ -0,0 +1,288 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _CBD_QUEUE_H
+#define _CBD_QUEUE_H
+
+#include "cbd_channel.h"
+#include "cbd_blkdev.h"
+
+#define cbd_queue_err(queue, fmt, ...) \
+ cbd_blk_err(queue->cbd_blkdev, "queue%d: " fmt, \
+ queue->channel.seg_id, ##__VA_ARGS__)
+#define cbd_queue_info(queue, fmt, ...) \
+ cbd_blk_info(queue->cbd_blkdev, "queue%d: " fmt, \
+ queue->channel.seg_id, ##__VA_ARGS__)
+#define cbd_queue_debug(queue, fmt, ...) \
+ cbd_blk_debug(queue->cbd_blkdev, "queue%d: " fmt, \
+ queue->channel.seg_id, ##__VA_ARGS__)
+
+struct cbd_request {
+ struct cbd_queue *cbdq;
+
+ struct cbd_se *se;
+ struct cbd_ce *ce;
+ struct request *req;
+
+ u64 off;
+ struct bio *bio;
+ u32 bio_off;
+ spinlock_t lock; /* race between cache and complete_work to access bio */
+
+ u8 op;
+ u64 req_tid;
+ struct list_head inflight_reqs_node;
+
+ u32 data_off;
+ u32 data_len;
+
+ struct work_struct work;
+
+ struct kref ref;
+ int ret;
+ struct cbd_request *parent;
+
+ void *priv_data;
+ void (*end_req)(struct cbd_request *cbd_req, void *priv_data);
+};
+
+struct cbd_cache_req {
+ struct cbd_cache *cache;
+ u8 op;
+ struct work_struct work;
+};
+
+#define CBD_SE_FLAGS_DONE 1
+
+static inline bool cbd_se_flags_test(struct cbd_se *se, u32 bit)
+{
+ return (se->flags & bit);
+}
+
+static inline void cbd_se_flags_set(struct cbd_se *se, u32 bit)
+{
+ se->flags |= bit;
+}
+
+enum cbd_queue_state {
+ cbd_queue_state_none = 0,
+ cbd_queue_state_running
+};
+
+struct cbd_queue {
+ struct cbd_blkdev *cbd_blkdev;
+ u32 index;
+ struct list_head inflight_reqs;
+ spinlock_t inflight_reqs_lock;
+ u64 req_tid;
+
+ u64 *released_extents;
+
+ struct cbd_channel_seg_info *channel_info;
+ struct cbd_channel channel;
+ struct cbd_channel_ctrl *channel_ctrl;
+
+ atomic_t state;
+
+ struct delayed_work complete_work;
+ struct cbd_worker_cfg complete_worker_cfg;
+};
+
+int cbd_queue_start(struct cbd_queue *cbdq, u32 channel_id);
+void cbd_queue_stop(struct cbd_queue *cbdq);
+extern const struct blk_mq_ops cbd_mq_ops;
+int cbd_queue_req_to_backend(struct cbd_request *cbd_req);
+void cbd_req_get(struct cbd_request *cbd_req);
+void cbd_req_put(struct cbd_request *cbd_req, int ret);
+void cbd_queue_advance(struct cbd_queue *cbdq, struct cbd_request *cbd_req);
+
+static inline struct cbd_se *get_submit_entry(struct cbd_queue *cbdq)
+{
+ return (struct cbd_se *)(cbdq->channel.submr + cbdc_submr_head_get(&cbdq->channel));
+}
+
+static inline struct cbd_se *get_oldest_se(struct cbd_queue *cbdq)
+{
+ if (cbdc_submr_tail_get(&cbdq->channel) == cbdc_submr_head_get(&cbdq->channel))
+ return NULL;
+
+ return (struct cbd_se *)(cbdq->channel.submr + cbdc_submr_tail_get(&cbdq->channel));
+}
+
+static inline bool queue_subm_ring_empty(struct cbd_queue *cbdq)
+{
+ return (cbdc_submr_tail_get(&cbdq->channel) == cbdc_submr_head_get(&cbdq->channel));
+}
+
+static inline struct cbd_ce *get_complete_entry(struct cbd_queue *cbdq)
+{
+ u32 ce_head = cbdc_compr_head_get(&cbdq->channel);
+
+ if (unlikely(ce_head > (cbdq->channel.compr_size - sizeof(struct cbd_ce))))
+ return NULL;
+
+ if (cbdc_compr_tail_get(&cbdq->channel) == cbdc_compr_head_get(&cbdq->channel))
+ return NULL;
+
+ return (struct cbd_ce *)(cbdq->channel.compr + cbdc_compr_tail_get(&cbdq->channel));
+}
+
+static inline 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_FLUSH:
+ return true;
+ default:
+ BUG();
+ }
+}
+
+static inline int copy_data_from_cbdreq(struct cbd_request *cbd_req)
+{
+ struct bio *bio = cbd_req->bio;
+ struct cbd_queue *cbdq = cbd_req->cbdq;
+ int ret;
+
+ spin_lock(&cbd_req->lock);
+ ret = cbdc_copy_to_bio(&cbdq->channel, cbd_req->data_off, cbd_req->data_len, bio, cbd_req->bio_off);
+ spin_unlock(&cbd_req->lock);
+
+ return ret;
+}
+
+static inline bool inflight_reqs_empty(struct cbd_queue *cbdq)
+{
+ bool empty;
+
+ spin_lock(&cbdq->inflight_reqs_lock);
+ empty = list_empty(&cbdq->inflight_reqs);
+ spin_unlock(&cbdq->inflight_reqs_lock);
+
+ return empty;
+}
+
+static inline void inflight_add_req(struct cbd_queue *cbdq, struct cbd_request *cbd_req)
+{
+ spin_lock(&cbdq->inflight_reqs_lock);
+ list_add_tail(&cbd_req->inflight_reqs_node, &cbdq->inflight_reqs);
+ spin_unlock(&cbdq->inflight_reqs_lock);
+}
+
+static inline void complete_inflight_req(struct cbd_queue *cbdq, struct cbd_request *cbd_req, int ret)
+{
+ if (cbd_req->op == CBD_OP_READ) {
+ int copy_ret = 0;
+
+ spin_lock(&cbdq->channel.submr_lock);
+ copy_ret = copy_data_from_cbdreq(cbd_req);
+ spin_unlock(&cbdq->channel.submr_lock);
+
+ if (!ret && copy_ret)
+ ret = copy_ret;
+ }
+
+ spin_lock(&cbdq->inflight_reqs_lock);
+ list_del_init(&cbd_req->inflight_reqs_node);
+ spin_unlock(&cbdq->inflight_reqs_lock);
+
+ cbd_se_flags_set(cbd_req->se, CBD_SE_FLAGS_DONE);
+ cbd_req_put(cbd_req, ret);
+}
+
+static inline struct cbd_request *find_inflight_req(struct cbd_queue *cbdq, u64 req_tid)
+{
+ struct cbd_request *req;
+ bool found = false;
+
+ spin_lock(&cbdq->inflight_reqs_lock);
+ list_for_each_entry(req, &cbdq->inflight_reqs, inflight_reqs_node) {
+ if (req->req_tid == req_tid) {
+ found = true;
+ break;
+ }
+ }
+ spin_unlock(&cbdq->inflight_reqs_lock);
+
+ if (found)
+ return req;
+
+ return NULL;
+}
+
+/**
+ * data_space_enough - Check if there is sufficient data space available in the cbd_queue.
+ * @cbdq: Pointer to the cbd_queue structure to check space in.
+ * @cbd_req: Pointer to the cbd_request structure for which space is needed.
+ *
+ * This function evaluates whether the cbd_queue has enough available data space
+ * to accommodate the data length required by the given cbd_request.
+ *
+ * The available space is calculated based on the current positions of the data_head
+ * and data_tail. If data_head is ahead of data_tail, it indicates that the space
+ * wraps around; otherwise, it calculates the space linearly.
+ *
+ * The space needed is rounded up according to the defined data alignment.
+ *
+ * If the available space minus the reserved space is less than the required space,
+ * the function returns false, indicating insufficient space. Otherwise, it returns true.
+ */
+static inline bool data_space_enough(struct cbd_queue *cbdq, struct cbd_request *cbd_req)
+{
+ struct cbd_channel *channel = &cbdq->channel;
+ u32 space_available = channel->data_size;
+ u32 space_needed;
+
+ if (channel->data_head > channel->data_tail) {
+ space_available = channel->data_size - channel->data_head;
+ space_available += channel->data_tail;
+ } else if (channel->data_head < channel->data_tail) {
+ space_available = channel->data_tail - channel->data_head;
+ }
+
+ space_needed = round_up(cbd_req->data_len, CBDC_DATA_ALIGN);
+
+ if (space_available - CBDC_DATA_RESERVED < space_needed)
+ return false;
+
+ return true;
+}
+
+/**
+ * submit_ring_full - Check if the submission ring is full.
+ * @cbdq: Pointer to the cbd_queue structure representing the submission queue.
+ *
+ * This function determines whether the submission ring buffer for the cbd_queue
+ * has enough available space to accept new entries.
+ *
+ * The available space is calculated based on the current positions of the
+ * submission ring head and tail. If the head is ahead of the tail, it indicates
+ * that the ring wraps around; otherwise, the available space is calculated
+ * linearly.
+ *
+ * A reserved space is maintained at the end of the ring to prevent it from
+ * becoming completely filled, ensuring that there is always some space available
+ * for processing. If the available space minus the reserved space is less than
+ * the size of a submission entry (cbd_se), the function returns true, indicating
+ * the ring is full. Otherwise, it returns false.
+ */
+static inline bool submit_ring_full(struct cbd_queue *cbdq)
+{
+ u32 space_available = cbdq->channel.submr_size;
+ struct cbd_channel *channel = &cbdq->channel;
+
+ if (cbdc_submr_head_get(channel) > cbdc_submr_tail_get(channel)) {
+ space_available = cbdq->channel.submr_size - cbdc_submr_head_get(channel);
+ space_available += cbdc_submr_tail_get(channel);
+ } else if (cbdc_submr_head_get(channel) < cbdc_submr_tail_get(channel)) {
+ space_available = cbdc_submr_tail_get(channel) - cbdc_submr_head_get(channel);
+ }
+
+ /* There is a SUBMR_RESERVED we dont use to prevent the ring to be used up */
+ if (space_available - CBDC_SUBMR_RESERVED < sizeof(struct cbd_se))
+ return true;
+
+ return false;
+}
+
+#endif /* _CBD_QUEUE_H */
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.dev> --- drivers/block/cbd/cbd_blkdev.c | 551 +++++++++++++++++++++++++++++++++ drivers/block/cbd/cbd_blkdev.h | 92 ++++++ drivers/block/cbd/cbd_queue.c | 516 ++++++++++++++++++++++++++++++ drivers/block/cbd/cbd_queue.h | 288 +++++++++++++++++ 4 files changed, 1447 insertions(+) create mode 100644 drivers/block/cbd/cbd_blkdev.c create mode 100644 drivers/block/cbd/cbd_blkdev.h create mode 100644 drivers/block/cbd/cbd_queue.c create mode 100644 drivers/block/cbd/cbd_queue.h