cbd_transport represents the layout of the entire shared memory, as shown below.
+-------------------------------------------------------------------------------------------------------------------------------+
| cbd transport |
+--------------------+-----------------------+-----------------------+----------------------+-----------------------------------+
| | hosts | backends | blkdevs | channels |
| cbd transport info +----+----+----+--------+----+----+----+--------+----+----+----+-------+-------+-------+-------+-----------+
| | | | | ... | | | | ... | | | | ... | | | | ... |
+--------------------+----+----+----+--------+----+----+----+--------+----+----+----+-------+---+---+---+---+-------+-----------+
| |
| |
| |
| |
+-------------------------------------------------------------------------------------+ |
| |
| |
v |
+-----------------------------------------------------------+ |
| channel segment | |
+--------------------+--------------------------------------+ |
| channel meta | channel data | |
+---------+----------+--------------------------------------+ |
| |
| |
| |
v |
+----------------------------------------------------------+ |
| channel meta | |
+-----------+--------------+-------------------------------+ |
| meta ctrl | comp ring | cmd ring | |
+-----------+--------------+-------------------------------+ |
|
|
|
+--------------------------------------------------------------------------------------------+
|
|
|
v
+----------------------------------------------------------+
| cache segment |
+-----------+----------------------------------------------+
| info | data |
+-----------+----------------------------------------------+
The shared memory is divided into five regions:
a) Transport_info:
Information about the overall transport, including the layout
of the transport.
b) Hosts:
Each host wishing to utilize this transport needs to register
its own information within a host entry in this region.
c) Backends:
Starting a backend on a host requires filling in information
in a backend entry within this region.
d) Blkdevs:
Once a backend is established, it can be mapped to CBD device
on any associated host. The information about the blkdevs is then
filled into the blkdevs region.
e) Segments:
This is the actual data communication area, where communication
between blkdev and backend occurs. Each queue of a block device uses
a channel, and each backend has a corresponding handler interacting
with this queue.
f) Channel segment:
Channel is one type of segment, is further divided into meta and
data regions.
The meta region includes subm rings and comp rings.
The blkdev converts upper-layer requests into cbd_se and fills
them into the subm ring. The handler accepts the cbd_se from
the subm ring and sends them to the local actual block device
of the backend (e.g., sda). After completion, the results are
formed into cbd_ce and filled into the comp ring. The blkdev
then receives the cbd_ce and returns the results to the upper-layer
IO sender.
g) Cache segment:
Cache segment is another type of segment, when cache enabled
for a backend, transport will allocate cache segments to this
backend.
Signed-off-by: Dongsheng Yang <dongsheng.yang@xxxxxxxxx>
---
drivers/block/cbd/cbd_internal.h | 1193 +++++++++++++++++++++++++++++
drivers/block/cbd/cbd_transport.c | 957 +++++++++++++++++++++++
2 files changed, 2150 insertions(+)
create mode 100644 drivers/block/cbd/cbd_internal.h
create mode 100644 drivers/block/cbd/cbd_transport.c
diff --git a/drivers/block/cbd/cbd_internal.h b/drivers/block/cbd/cbd_internal.h
new file mode 100644
index 000000000000..236dbcb62906
--- /dev/null
+++ b/drivers/block/cbd/cbd_internal.h
@@ -0,0 +1,1193 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CBD_INTERNAL_H
+#define _CBD_INTERNAL_H
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/blk-mq.h>
+#include <asm/byteorder.h>
+#include <asm/types.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/dax.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/parser.h>
+#include <linux/idr.h>
+#include <linux/workqueue.h>
+#include <linux/uuid.h>
+#include <linux/bitfield.h>
+#include <linux/crc32.h>
+#include <linux/hashtable.h>
+
+/*
+ * CBD (CXL Block Device) provides two usage scenarios: single-host and multi-hosts.
+ *
+ * (1) Single-host scenario, CBD can use a pmem device as a cache for block devices,
+ * providing a caching mechanism specifically designed for persistent memory.
+ *
+ * +-----------------------------------------------------------------+
+ * | single-host |
+ * +-----------------------------------------------------------------+
+ * | |
+ * | |
+ * | |
+ * | |
+ * | |
+ * | +-----------+ +------------+ |
+ * | | /dev/cbd0 | | /dev/cbd1 | |
+ * | | | | | |
+ * | +---------------------|-----------|-----|------------|-------+ |
+ * | | | | | | | |
+ * | | /dev/pmem0 | cbd0 cache| | cbd1 cache | | |
+ * | | | | | | | |
+ * | +---------------------|-----------|-----|------------|-------+ |
+ * | |+---------+| |+----------+| |
+ * | ||/dev/sda || || /dev/sdb || |
+ * | |+---------+| |+----------+| |
+ * | +-----------+ +------------+ |
+ * +-----------------------------------------------------------------+
+ *
+ * (2) Multi-hosts scenario, CBD also provides a cache while taking advantage of
+ * shared memory features, allowing users to access block devices on other nodes across
+ * different hosts.
+ *
+ * As shared memory is supported in CXL3.0 spec, we can transfer data via CXL shared memory.
+ * CBD use CXL shared memory to transfer data between node-1 and node-2.
+ *
+ * +--------------------------------------------------------------------------------------------------------+
+ * | multi-hosts |
+ * +--------------------------------------------------------------------------------------------------------+
+ * | |
+ * | |
+ * | +-------------------------------+ +------------------------------------+ |
+ * | | node-1 | | node-2 | |
+ * | +-------------------------------+ +------------------------------------+ |
+ * | | | | | |
+ * | | +-------+ +---------+ | |
+ * | | | cbd0 | | backend0+------------------+ | |
+ * | | +-------+ +---------+ | | |
+ * | | | pmem0 | | pmem0 | v | |
+ * | | +-------+-------+ +---------+----+ +---------------+ |
+ * | | | cxl driver | | cxl driver | | /dev/sda | |
+ * | +---------------+--------+------+ +-----+--------+-----+---------------+ |
+ * | | | |
+ * | | | |
+ * | | CXL CXL | |
+ * | +----------------+ +-----------+ |
+ * | | | |
+ * | | | |
+ * | | | |
+ * | +-------------------------+---------------+--------------------------+ |
+ * | | +---------------+ | |
+ * | | shared memory device | cbd0 cache | | |
+ * | | +---------------+ | |
+ * | +--------------------------------------------------------------------+ |
+ * | |
+ * +--------------------------------------------------------------------------------------------------------+
+ */
+
+#define cbd_err(fmt, ...) \
+ pr_err("cbd: %s:%u " fmt, __func__, __LINE__, ##__VA_ARGS__)
+#define cbd_info(fmt, ...) \
+ pr_info("cbd: %s:%u " fmt, __func__, __LINE__, ##__VA_ARGS__)
+#define cbd_debug(fmt, ...) \
+ pr_debug("cbd: %s:%u " fmt, __func__, __LINE__, ##__VA_ARGS__)
+
+#define cbdt_err(transport, fmt, ...) \
+ cbd_err("cbd_transport%u: " fmt, \
+ transport->id, ##__VA_ARGS__)
+#define cbdt_info(transport, fmt, ...) \
+ cbd_info("cbd_transport%u: " fmt, \
+ transport->id, ##__VA_ARGS__)
+#define cbdt_debug(transport, fmt, ...) \
+ cbd_debug("cbd_transport%u: " fmt, \
+ transport->id, ##__VA_ARGS__)
+
+#define cbdb_err(backend, fmt, ...) \
+ cbdt_err(backend->cbdt, "backend%d: " fmt, \
+ backend->backend_id, ##__VA_ARGS__)
+#define cbdb_info(backend, fmt, ...) \
+ cbdt_info(backend->cbdt, "backend%d: " fmt, \
+ backend->backend_id, ##__VA_ARGS__)
+#define cbdbdebug(backend, fmt, ...) \
+ cbdt_debug(backend->cbdt, "backend%d: " fmt, \
+ backend->backend_id, ##__VA_ARGS__)
+
+#define cbd_handler_err(handler, fmt, ...) \
+ cbdb_err(handler->cbdb, "handler%d: " fmt, \
+ handler->channel.seg_id, ##__VA_ARGS__)
+#define cbd_handler_info(handler, fmt, ...) \
+ cbdb_info(handler->cbdb, "handler%d: " fmt, \
+ handler->channel.seg_id, ##__VA_ARGS__)
+#define cbd_handler_debug(handler, fmt, ...) \
+ cbdb_debug(handler->cbdb, "handler%d: " fmt, \
+ handler->channel.seg_id, ##__VA_ARGS__)
+
+#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__)
+
+#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__)
+
+#define cbd_channel_err(channel, fmt, ...) \
+ cbdt_err(channel->cbdt, "channel%d: " fmt, \
+ channel->seg_id, ##__VA_ARGS__)
+#define cbd_channel_info(channel, fmt, ...) \
+ cbdt_info(channel->cbdt, "channel%d: " fmt, \
+ channel->seg_id, ##__VA_ARGS__)
+#define cbd_channel_debug(channel, fmt, ...) \
+ cbdt_debug(channel->cbdt, "channel%d: " fmt, \
+ channel->seg_id, ##__VA_ARGS__)
+
+#define cbd_cache_err(cache, fmt, ...) \
+ cbdt_err(cache->cbdt, "cache%d: " fmt, \
+ cache->cache_id, ##__VA_ARGS__)
+#define cbd_cache_info(cache, fmt, ...) \
+ cbdt_info(cache->cbdt, "cache%d: " fmt, \
+ cache->cache_id, ##__VA_ARGS__)
+#define cbd_cache_debug(cache, fmt, ...) \
+ cbdt_debug(cache->cbdt, "cache%d: " fmt, \
+ cache->cache_id, ##__VA_ARGS__)
+
+#define CBD_KB (1024)
+#define CBD_MB (CBD_KB * CBD_KB)
+
+#define CBD_TRANSPORT_MAX 1024
+#define CBD_PATH_LEN 512
+#define CBD_NAME_LEN 32
+
+#define CBD_QUEUES_MAX 128
+
+#define CBD_PART_SHIFT 4
+#define CBD_DRV_NAME "cbd"
+#define CBD_DEV_NAME_LEN 32
+
+#define CBD_HB_INTERVAL msecs_to_jiffies(5000) /* 5s */
+#define CBD_HB_TIMEOUT (30 * 1000) /* 30s */
+
+/*
+ * CBD transport layout:
+ *
+ * +-------------------------------------------------------------------------------------------------------------------------------+
+ * | cbd transport |
+ * +--------------------+-----------------------+-----------------------+----------------------+-----------------------------------+
+ * | | hosts | backends | blkdevs | channels |
+ * | cbd transport info +----+----+----+--------+----+----+----+--------+----+----+----+-------+-------+-------+-------+-----------+
+ * | | | | | ... | | | | ... | | | | ... | | | | ... |
+ * +--------------------+----+----+----+--------+----+----+----+--------+----+----+----+-------+---+---+---+---+-------+-----------+
+ * | |
+ * | |
+ * | |
+ * | |
+ * +-------------------------------------------------------------------------------------+ |
+ * | |
+ * | |
+ * v |
+ * +-----------------------------------------------------------+ |
+ * | channel segment | |
+ * +--------------------+--------------------------------------+ |
+ * | channel meta | channel data | |
+ * +---------+----------+--------------------------------------+ |
+ * | |
+ * | |
+ * | |
+ * v |
+ * +----------------------------------------------------------+ |
+ * | channel meta | |
+ * +-----------+--------------+-------------------------------+ |
+ * | meta ctrl | comp ring | cmd ring | |
+ * +-----------+--------------+-------------------------------+ |
+ * |
+ * |
+ * |
+ * +--------------------------------------------------------------------------------------------+
+ * |
+ * |
+ * |
+ * v
+ * +----------------------------------------------------------+
+ * | cache segment |
+ * +-----------+----------------------------------------------+
+ * | info | data |
+ * +-----------+----------------------------------------------+
+ */
+
+/* cbd segment */
+#define CBDT_SEG_SIZE (16 * 1024 * 1024)
+
+/* cbd channel seg */
+#define CBDC_META_SIZE (4 * 1024 * 1024)
+#define CBDC_SUBMR_RESERVED sizeof(struct cbd_se)
+#define CBDC_CMPR_RESERVED sizeof(struct cbd_ce)
+
+#define CBDC_DATA_ALIGH 4096
+#define CBDC_DATA_RESERVED CBDC_DATA_ALIGH
+
+#define CBDC_CTRL_OFF 0
+#define CBDC_CTRL_SIZE PAGE_SIZE
+#define CBDC_COMPR_OFF (CBDC_CTRL_OFF + CBDC_CTRL_SIZE)
+#define CBDC_COMPR_SIZE (sizeof(struct cbd_ce) * 1024)
+#define CBDC_SUBMR_OFF (CBDC_COMPR_OFF + CBDC_COMPR_SIZE)
+#define CBDC_SUBMR_SIZE (CBDC_META_SIZE - CBDC_SUBMR_OFF)
+
+#define CBDC_DATA_OFF CBDC_META_SIZE
+#define CBDC_DATA_SIZE (CBDT_SEG_SIZE - CBDC_META_SIZE)
+
+#define CBDC_UPDATE_SUBMR_HEAD(head, used, size) (head = ((head % size) + used) % size)
+#define CBDC_UPDATE_SUBMR_TAIL(tail, used, size) (tail = ((tail % size) + used) % size)
+
+#define CBDC_UPDATE_COMPR_HEAD(head, used, size) (head = ((head % size) + used) % size)
+#define CBDC_UPDATE_COMPR_TAIL(tail, used, size) (tail = ((tail % size) + used) % size)
+
+/* cbd transport */
+#define CBD_TRANSPORT_MAGIC 0x65B05EFA96C596EFULL
+#define CBD_TRANSPORT_VERSION 1
+
+#define CBDT_INFO_OFF 0
+#define CBDT_INFO_SIZE PAGE_SIZE
+
+#define CBDT_HOST_INFO_SIZE round_up(sizeof(struct cbd_host_info), PAGE_SIZE)
+#define CBDT_BACKEND_INFO_SIZE round_up(sizeof(struct cbd_backend_info), PAGE_SIZE)
+#define CBDT_BLKDEV_INFO_SIZE round_up(sizeof(struct cbd_blkdev_info), PAGE_SIZE)
+
+#define CBD_TRASNPORT_SIZE_MIN (512 * 1024 * 1024)
+
+/*
+ * CBD structure diagram:
+ *
+ * +--------------+
+ * | cbd_transport| +----------+
+ * +--------------+ | cbd_host |
+ * | | +----------+
+ * | host +---------------------------------------------->| |
+ * +--------------------+ backends | | hostname |
+ * | | devices +------------------------------------------+ | |
+ * | | | | +----------+
+ * | +--------------+ |
+ * | |
+ * | |
+ * | |
+ * | |
+ * | |
+ * v v
+ * +------------+ +-----------+ +------+ +-----------+ +-----------+ +------+
+ * | cbd_backend+---->|cbd_backend+---->| NULL | | cbd_blkdev+----->| cbd_blkdev+---->| NULL |
+ * +------------+ +-----------+ +------+ +-----------+ +-----------+ +------+
+ * +------------+ cbd_cache | | handlers | +------+ queues | | queues |
+ * | | | +-----------+ | | | +-----------+
+ * | +------+ handlers | | | |
+ * | | +------------+ | | cbd_cache +-------------------------------------+
+ * | | | +-----------+ |
+ * | | | |
+ * | | +-------------+ +-------------+ +------+ | +-----------+ +-----------+ +------+ |
+ * | +----->| cbd_handler +------>| cbd_handler +---------->| NULL | +----->| cbd_queue +----->| cbd_queue +---->| NULL | |
+ * | +-------------+ +-------------+ +------+ +-----------+ +-----------+ +------+ |
+ * | +------+ channel | | channel | +------+ channel | | channel | |
+ * | | +-------------+ +-------------+ | +-----------+ +-----------+ |
+ * | | | |
+ * | | | |
+ * | | | |
+ * | | v |
+ * | | +-----------------------+ |
+ * | +------------------------------------------------------->| cbd_channel | |
+ * | +-----------------------+ |
+ * | | channel_id | |
+ * | | cmdr (cmd ring) | |
+ * | | compr (complete ring) | |
+ * | | data (data area) | |
+ * | | | |
+ * | +-----------------------+ |
+ * | |
+ * | +-----------------------------+ |
+ * +------------------------------------------------>| cbd_cache |<------------------------------------------------------------+
+ * +-----------------------------+
+ * | cache_wq |
+ * | cache_tree |
+ * | segments[] |
+ * +-----------------------------+
+ */
+
+#define CBD_DEVICE(OBJ) \
+struct cbd_## OBJ ##_device { \
+ struct device dev; \
+ struct cbd_transport *cbdt; \
+ struct cbd_## OBJ ##_info *OBJ##_info; \
+}; \
+ \
+struct cbd_## OBJ ##s_device { \
+ struct device OBJ ##s_dev; \
+ struct cbd_## OBJ ##_device OBJ ##_devs[]; \
+}
+
+/* cbd_worker_cfg*/
+struct cbd_worker_cfg {
+ u32 busy_retry_cur;
+ u32 busy_retry_count;
+ u32 busy_retry_max;
+ u32 busy_retry_min;
+ u64 busy_retry_interval;
+};
+
+static inline void cbdwc_init(struct cbd_worker_cfg *cfg)
+{
+ /* init cbd_worker_cfg with default values */
+ cfg->busy_retry_cur = 0;
+ cfg->busy_retry_count = 100;
+ cfg->busy_retry_max = cfg->busy_retry_count * 2;
+ cfg->busy_retry_min = 0;
+ cfg->busy_retry_interval = 1; /* 1us */
+}
+
+/* reset retry_cur and increase busy_retry_count */
+static inline void cbdwc_hit(struct cbd_worker_cfg *cfg)
+{
+ u32 delta;
+
+ cfg->busy_retry_cur = 0;
+
+ if (cfg->busy_retry_count == cfg->busy_retry_max)
+ return;
+
+ /* retry_count increase by 1/16 */
+ delta = cfg->busy_retry_count >> 4;
+ if (!delta)
+ delta = (cfg->busy_retry_max + cfg->busy_retry_min) >> 1;
+
+ cfg->busy_retry_count += delta;
+
+ if (cfg->busy_retry_count > cfg->busy_retry_max)
+ cfg->busy_retry_count = cfg->busy_retry_max;
+}
+
+/* reset retry_cur and decrease busy_retry_count */
+static inline void cbdwc_miss(struct cbd_worker_cfg *cfg)
+{
+ u32 delta;
+
+ cfg->busy_retry_cur = 0;
+
+ if (cfg->busy_retry_count == cfg->busy_retry_min)
+ return;
+
+ /* retry_count decrease by 1/16 */
+ delta = cfg->busy_retry_count >> 4;
+ if (!delta)
+ delta = cfg->busy_retry_count;
+
+ cfg->busy_retry_count -= delta;
+}
+
+static inline bool cbdwc_need_retry(struct cbd_worker_cfg *cfg)
+{
+ if (++cfg->busy_retry_cur < cfg->busy_retry_count) {
+ cpu_relax();
+ fsleep(cfg->busy_retry_interval);
+ return true;
+ }
+
+ return false;
+}
+
+/* cbd_transport */
+#define CBDT_INFO_F_BIGENDIAN (1 << 0)
+#define CBDT_INFO_F_CRC (1 << 1)
+
+#ifdef CONFIG_CBD_MULTIHOST
+#define CBDT_HOSTS_MAX 16
+#else
+#define CBDT_HOSTS_MAX 1
+#endif /*CONFIG_CBD_MULTIHOST*/
+
+struct cbd_transport_info {
+ __le64 magic;
+ __le16 version;
+ __le16 flags;
+
+ u32 hosts_registered;
+
+ u64 host_area_off;
+ u32 host_info_size;
+ u32 host_num;
+
+ u64 backend_area_off;
+ u32 backend_info_size;
+ u32 backend_num;
+
+ u64 blkdev_area_off;
+ u32 blkdev_info_size;
+ u32 blkdev_num;
+
+ u64 segment_area_off;
+ u32 segment_size;
+ u32 segment_num;
+};
+
+struct cbd_transport {
+ u16 id;
+ struct device device;
+ struct mutex lock;
+ struct mutex adm_lock;
+
+ struct cbd_transport_info *transport_info;
+
+ struct cbd_host *host;
+ struct list_head backends;
+ struct list_head devices;
+
+ struct cbd_hosts_device *cbd_hosts_dev;
+ struct cbd_segments_device *cbd_segments_dev;
+ struct cbd_backends_device *cbd_backends_dev;
+ struct cbd_blkdevs_device *cbd_blkdevs_dev;
+
+ struct dax_device *dax_dev;
+ struct file *bdev_file;
+};
+
+struct cbdt_register_options {
+ char hostname[CBD_NAME_LEN];
+ char path[CBD_PATH_LEN];
+ u16 format:1;
+ u16 force:1;
+ u16 unused:15;
+};
+
+struct cbd_blkdev;
+struct cbd_backend;
+struct cbd_backend_io;
+struct cbd_cache;
+
+int cbdt_register(struct cbdt_register_options *opts);
+int cbdt_unregister(u32 transport_id);
+
+struct cbd_host_info *cbdt_get_host_info(struct cbd_transport *cbdt, u32 id);
+struct cbd_backend_info *cbdt_get_backend_info(struct cbd_transport *cbdt, u32 id);
+struct cbd_blkdev_info *cbdt_get_blkdev_info(struct cbd_transport *cbdt, u32 id);
+struct cbd_segment_info *cbdt_get_segment_info(struct cbd_transport *cbdt, u32 id);
+static inline struct cbd_channel_info *cbdt_get_channel_info(struct cbd_transport *cbdt, u32 id)
+{
+ return (struct cbd_channel_info *)cbdt_get_segment_info(cbdt, id);
+}
+
+int cbdt_get_empty_host_id(struct cbd_transport *cbdt, u32 *id);
+int cbdt_get_empty_backend_id(struct cbd_transport *cbdt, u32 *id);
+int cbdt_get_empty_blkdev_id(struct cbd_transport *cbdt, u32 *id);
+int cbdt_get_empty_segment_id(struct cbd_transport *cbdt, u32 *id);
+
+void cbdt_add_backend(struct cbd_transport *cbdt, struct cbd_backend *cbdb);
+void cbdt_del_backend(struct cbd_transport *cbdt, struct cbd_backend *cbdb);
+struct cbd_backend *cbdt_get_backend(struct cbd_transport *cbdt, u32 id);
+void cbdt_add_blkdev(struct cbd_transport *cbdt, struct cbd_blkdev *blkdev);
+void cbdt_del_blkdev(struct cbd_transport *cbdt, struct cbd_blkdev *blkdev);
+struct cbd_blkdev *cbdt_get_blkdev(struct cbd_transport *cbdt, u32 id);
+
+struct page *cbdt_page(struct cbd_transport *cbdt, u64 transport_off, u32 *page_off);
+void cbdt_zero_range(struct cbd_transport *cbdt, void *pos, u32 size);
+
+/* cbd_host */
+CBD_DEVICE(host);
+
+enum cbd_host_state {
+ cbd_host_state_none = 0,
+ cbd_host_state_running,
+ cbd_host_state_removing
+};
+
+struct cbd_host_info {
+ u8 state;
+ u64 alive_ts;
+ char hostname[CBD_NAME_LEN];
+};
+
+struct cbd_host {
+ u32 host_id;
+ struct cbd_transport *cbdt;
+
+ struct cbd_host_device *dev;
+ struct cbd_host_info *host_info;
+ struct delayed_work hb_work; /* heartbeat work */
+};
+
+int cbd_host_register(struct cbd_transport *cbdt, char *hostname);
+int cbd_host_unregister(struct cbd_transport *cbdt);
+int cbd_host_clear(struct cbd_transport *cbdt, u32 host_id);
+bool cbd_host_info_is_alive(struct cbd_host_info *info);
+
+/* cbd_segment */
+CBD_DEVICE(segment);
+
+enum cbd_segment_state {
+ cbd_segment_state_none = 0,
+ cbd_segment_state_running,
+ cbd_segment_state_removing
+};
+
+enum cbd_seg_type {
+ cbds_type_none = 0,
+ cbds_type_channel,
+ cbds_type_cache
+};
+
+static inline const char *cbds_type_str(enum cbd_seg_type type)
+{
+ if (type == cbds_type_channel)
+ return "channel";
+ else if (type == cbds_type_cache)
+ return "cache";
+
+ return "Unknown";
+}
+
+struct cbd_segment_info {
+ u8 state;
+ u8 type;
+ u8 ref;
+ u32 next_seg;
+ u64 alive_ts;
+};
+
+struct cbd_seg_pos {
+ struct cbd_segment *segment;
+ u32 off;
+};
+
+struct cbd_seg_ops {
+ void (*sanitize_pos)(struct cbd_seg_pos *pos);
+};
+
+struct cbds_init_options {
+ u32 seg_id;
+ enum cbd_seg_type type;
+ u32 data_off;
+ struct cbd_seg_ops *seg_ops;
+ void *priv_data;
+};
+
+struct cbd_segment {
+ struct cbd_transport *cbdt;
+ struct cbd_segment *next;
+
+ u32 seg_id;
+ struct cbd_segment_info *segment_info;
+ struct cbd_seg_ops *seg_ops;
+
+ void *data;
+ u32 data_size;
+
+ void *priv_data;
+
+ struct delayed_work hb_work; /* heartbeat work */
+};
+
+int cbd_segment_clear(struct cbd_transport *cbdt, u32 segment_id);
+void cbd_segment_init(struct cbd_transport *cbdt, struct cbd_segment *segment,
+ struct cbds_init_options *options);
+void cbd_segment_exit(struct cbd_segment *segment);
+bool cbd_segment_info_is_alive(struct cbd_segment_info *info);
+void cbds_copy_to_bio(struct cbd_segment *segment,
+ u32 data_off, u32 data_len, struct bio *bio, u32 bio_off);
+void cbds_copy_from_bio(struct cbd_segment *segment,
+ u32 data_off, u32 data_len, struct bio *bio, u32 bio_off);
+u32 cbd_seg_crc(struct cbd_segment *segment, u32 data_off, u32 data_len);
+int cbds_map_pages(struct cbd_segment *segment, struct cbd_backend_io *io);
+int cbds_pos_advance(struct cbd_seg_pos *seg_pos, u32 len);
+void cbds_copy_data(struct cbd_seg_pos *dst_pos,
+ struct cbd_seg_pos *src_pos, u32 len);
+
+/* cbd_channel */
+
+enum cbdc_blkdev_state {
+ cbdc_blkdev_state_none = 0,
+ cbdc_blkdev_state_running,
+ cbdc_blkdev_state_stopped,
+};
+
+enum cbdc_backend_state {
+ cbdc_backend_state_none = 0,
+ cbdc_backend_state_running,
+ cbdc_backend_state_stopped,
+};
+
+struct cbd_channel_info {
+ struct cbd_segment_info seg_info; /* must be the first member */
+ u8 blkdev_state;
+ u32 blkdev_id;
+
+ u8 backend_state;
+ u32 backend_id;
+
+ u32 polling:1;
+
+ u32 submr_head;
+ u32 submr_tail;
+
+ u32 compr_head;
+ u32 compr_tail;
+};
+
+struct cbd_channel {
+ u32 seg_id;
+ struct cbd_segment segment;
+
+ struct cbd_channel_info *channel_info;
+
+ struct cbd_transport *cbdt;
+
+ void *submr;
+ void *compr;
+
+ u32 submr_size;
+ u32 compr_size;
+
+ u32 data_size;
+ u32 data_head;
+ u32 data_tail;
+
+ spinlock_t submr_lock;
+ spinlock_t compr_lock;
+};
+
+void cbd_channel_init(struct cbd_channel *channel, struct cbd_transport *cbdt, u32 seg_id);
+void cbd_channel_exit(struct cbd_channel *channel);
+void cbdc_copy_from_bio(struct cbd_channel *channel,
+ u32 data_off, u32 data_len, struct bio *bio, u32 bio_off);
+void cbdc_copy_to_bio(struct cbd_channel *channel,
+ u32 data_off, u32 data_len, struct bio *bio, u32 bio_off);
+u32 cbd_channel_crc(struct cbd_channel *channel, u32 data_off, u32 data_len);
+int cbdc_map_pages(struct cbd_channel *channel, struct cbd_backend_io *io);
+int cbd_get_empty_channel_id(struct cbd_transport *cbdt, u32 *id);
+ssize_t cbd_channel_seg_detail_show(struct cbd_channel_info *channel_info, char *buf);
+
+/* cbd cache */
+struct cbd_cache_seg_info {
+ struct cbd_segment_info segment_info; /* first member */
+ u32 flags;
+ u32 next_cache_seg_id; /* index in cache->segments */
+ u64 gen;
+};
+
+#define CBD_CACHE_SEG_FLAGS_HAS_NEXT (1 << 0)
+#define CBD_CACHE_SEG_FLAGS_WB_DONE (1 << 1)
+#define CBD_CACHE_SEG_FLAGS_GC_DONE (1 << 2)
+
+enum cbd_cache_blkdev_state {
+ cbd_cache_blkdev_state_none = 0,
+ cbd_cache_blkdev_state_running,
+ cbd_cache_blkdev_state_removing
+};
+
+struct cbd_cache_segment {
+ struct cbd_cache *cache;
+ u32 cache_seg_id; /* index in cache->segments */
+ u32 used;
+ spinlock_t gen_lock;
+ struct cbd_cache_seg_info *cache_seg_info;
+ struct cbd_segment segment;
+ atomic_t refs;
+};
+
+struct cbd_cache_pos {
+ struct cbd_cache_segment *cache_seg;
+ u32 seg_off;
+};
+
+struct cbd_cache_pos_onmedia {
+ u32 cache_seg_id;
+ u32 seg_off;
+};
+
+struct cbd_cache_info {
+ u8 blkdev_state;
+ u32 blkdev_id;
+
+ u32 seg_id;
+ u32 n_segs;
+
+ u32 used_segs;
+ u16 gc_percent;
+
+ struct cbd_cache_pos_onmedia key_tail_pos;
+ struct cbd_cache_pos_onmedia dirty_tail_pos;
+};
+
+struct cbd_cache_tree {
+ struct rb_root root;
+ spinlock_t tree_lock;
+};
+
+struct cbd_cache_data_head {
+ spinlock_t data_head_lock;
+ struct cbd_cache_pos head_pos;
+};
+
+struct cbd_cache_key {
+ struct cbd_cache *cache;
+ struct cbd_cache_tree *cache_tree;
+ struct kref ref;
+
+ struct rb_node rb_node;
+ struct list_head list_node;
+
+ u64 off;
+ u32 len;
+ u64 flags;
+
+ struct cbd_cache_pos cache_pos;
+
+ u64 seg_gen;
+#ifdef CONFIG_CBD_CRC
+ u32 data_crc;
+#endif
+};
+
+#define CBD_CACHE_KEY_FLAGS_EMPTY (1 << 0)
+#define CBD_CACHE_KEY_FLAGS_CLEAN (1 << 1)
+
+struct cbd_cache_key_onmedia {
+ u64 off;
+ u32 len;
+
+ u32 flags;
+
+ u32 cache_seg_id;
+ u32 cache_seg_off;
+
+ u64 seg_gen;
+#ifdef CONFIG_CBD_CRC
+ u32 data_crc;
+#endif
+};
+
+struct cbd_cache_kset_onmedia {
+ u32 crc;
+ u64 magic;
+ u64 flags;
+ u32 key_num;
+ struct cbd_cache_key_onmedia data[];
+};
+
+#define CBD_KSET_FLAGS_LAST (1 << 0)
+
+#define CBD_KSET_MAGIC 0x676894a64e164f1aULL
+
+struct cbd_cache_kset {
+ struct cbd_cache *cache;
+ spinlock_t kset_lock;
+ struct delayed_work flush_work;
+ struct cbd_cache_kset_onmedia kset_onmedia;
+};
+
+enum cbd_cache_state {
+ cbd_cache_state_none = 0,
+ cbd_cache_state_running,
+ cbd_cache_state_stopping
+};
+
+struct cbd_cache {
+ struct cbd_transport *cbdt;
+ struct cbd_cache_info *cache_info;
+ u32 cache_id; /* same with related backend->backend_id */
+
+ u32 n_heads;
+ struct cbd_cache_data_head *data_heads;
+
+ spinlock_t key_head_lock;
+ struct cbd_cache_pos key_head;
+ u32 n_ksets;
+ struct cbd_cache_kset *ksets;
+
+ struct cbd_cache_pos key_tail;
+ struct cbd_cache_pos dirty_tail;
+
+ struct kmem_cache *key_cache;
+ u32 n_trees;
+ struct cbd_cache_tree *cache_trees;
+ struct work_struct clean_work;
+
+ spinlock_t miss_read_reqs_lock;
+ struct list_head miss_read_reqs;
+ struct work_struct miss_read_end_work;
+
+ struct workqueue_struct *cache_wq;
+
+ struct file *bdev_file;
+ u64 dev_size;
+ struct delayed_work writeback_work;
+ struct delayed_work gc_work;
+ struct bio_set *bioset;
+
+ struct kmem_cache *req_cache;
+
+ u32 state:8;
+ u32 init_keys:1;
+ u32 start_writeback:1;
+ u32 start_gc:1;
+
+ u32 n_segs;
+ unsigned long *seg_map;
+ u32 last_cache_seg;
+ spinlock_t seg_map_lock;
+ struct cbd_cache_segment segments[]; /* should be the last member */
+};
+
+struct cbd_request;
+struct cbd_cache_opts {
+ struct cbd_cache_info *cache_info;
+ bool alloc_segs;
+ bool start_writeback;
+ bool start_gc;
+ bool init_keys;
+ u64 dev_size;
+ u32 n_paral;
+ struct file *bdev_file; /* needed for start_writeback is true */
+};
+
+struct cbd_cache *cbd_cache_alloc(struct cbd_transport *cbdt,
+ struct cbd_cache_opts *opts);
+void cbd_cache_destroy(struct cbd_cache *cache);
+int cbd_cache_handle_req(struct cbd_cache *cache, struct cbd_request *cbd_req);
+
+/* cbd_handler */
+struct cbd_handler {
+ struct cbd_backend *cbdb;
+ struct cbd_channel_info *channel_info;
+
+ struct cbd_channel channel;
+ spinlock_t compr_lock;
+
+ u32 se_to_handle;
+ u64 req_tid_expected;
+
+ u32 polling:1;
+
+ struct delayed_work handle_work;
+ struct cbd_worker_cfg handle_worker_cfg;
+
+ struct hlist_node hash_node;
+ struct bio_set bioset;
+};
+
+void cbd_handler_destroy(struct cbd_handler *handler);
+int cbd_handler_create(struct cbd_backend *cbdb, u32 seg_id);
+void cbd_handler_notify(struct cbd_handler *handler);
+
+/* cbd_backend */
+CBD_DEVICE(backend);
+
+enum cbd_backend_state {
+ cbd_backend_state_none = 0,
+ cbd_backend_state_running,
+ cbd_backend_state_removing
+};
+
+#define CBDB_BLKDEV_COUNT_MAX 1
+
+struct cbd_backend_info {
+ u8 state;
+ u32 host_id;
+ u32 blkdev_count;
+ u64 alive_ts;
+ u64 dev_size; /* nr_sectors */
+ struct cbd_cache_info cache_info;
+
+ char path[CBD_PATH_LEN];
+};
+
+struct cbd_backend_io {
+ struct cbd_se *se;
+ u64 off;
+ u32 len;
+ struct bio *bio;
+ struct cbd_handler *handler;
+};
+
+#define CBD_BACKENDS_HANDLER_BITS 7
+
+struct cbd_backend {
+ u32 backend_id;
+ char path[CBD_PATH_LEN];
+ struct cbd_transport *cbdt;
+ struct cbd_backend_info *backend_info;
+ spinlock_t lock;
+
+ struct block_device *bdev;
+ struct file *bdev_file;
+
+ struct workqueue_struct *task_wq;
+ struct delayed_work state_work;
+ struct delayed_work hb_work; /* heartbeat work */
+
+ struct list_head node; /* cbd_transport->backends */
+ DECLARE_HASHTABLE(handlers_hash, CBD_BACKENDS_HANDLER_BITS);
+
+ struct cbd_backend_device *backend_device;
+
+ struct kmem_cache *backend_io_cache;
+
+ struct cbd_cache *cbd_cache;
+ struct device cache_dev;
+ bool cache_dev_registered;
+};
+
+int cbd_backend_start(struct cbd_transport *cbdt, char *path, u32 backend_id, u32 cache_segs);
+int cbd_backend_stop(struct cbd_transport *cbdt, u32 backend_id);
+int cbd_backend_clear(struct cbd_transport *cbdt, u32 backend_id);
+int cbdb_add_handler(struct cbd_backend *cbdb, struct cbd_handler *handler);
+void cbdb_del_handler(struct cbd_backend *cbdb, struct cbd_handler *handler);
+bool cbd_backend_info_is_alive(struct cbd_backend_info *info);
+bool cbd_backend_cache_on(struct cbd_backend_info *backend_info);
+void cbd_backend_notify(struct cbd_backend *cbdb, u32 seg_id);
+
+/* cbd_queue */
+enum cbd_op {
+ CBD_OP_WRITE = 0,
+ CBD_OP_READ,
+ CBD_OP_FLUSH,
+};
+
+struct cbd_se {
+#ifdef CONFIG_CBD_CRC
+ u32 se_crc; /* should be the first member */
+ u32 data_crc;
+#endif
+ u32 op;
+ u32 flags;
+ u64 req_tid;
+
+ u64 offset;
+ u32 len;
+
+ u32 data_off;
+ u32 data_len;
+};
+
+struct cbd_ce {
+#ifdef CONFIG_CBD_CRC
+ u32 ce_crc; /* should be the first member */
+ u32 data_crc;
+#endif
+ u64 req_tid;
+ u32 result;
+ u32 flags;
+};
+
+#ifdef CONFIG_CBD_CRC
+static inline u32 cbd_se_crc(struct cbd_se *se)
+{
+ return crc32(0, (void *)se + 4, sizeof(*se) - 4);
+}
+
+static inline u32 cbd_ce_crc(struct cbd_ce *ce)
+{
+ return crc32(0, (void *)ce + 4, sizeof(*ce) - 4);
+}
+#endif
+
+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 */
+
+ enum cbd_op 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;
+ enum cbd_op 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,
+ cbd_queue_state_removing
+};
+
+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_info *channel_info;
+ struct cbd_channel channel;
+
+ atomic_t state;
+
+ struct delayed_work complete_work;
+ struct cbd_worker_cfg complete_worker_cfg;
+};
+
+int cbd_queue_start(struct cbd_queue *cbdq);
+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);
+
+/* cbd_blkdev */
+CBD_DEVICE(blkdev);
+
+enum cbd_blkdev_state {
+ cbd_blkdev_state_none = 0,
+ cbd_blkdev_state_running,
+ cbd_blkdev_state_removing
+};
+
+struct cbd_blkdev_info {
+ 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 cbd_transport *cbdt;
+
+ 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, bool force);
+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_setup_device(DEV, PARENT, TYPE, fmt, ...) \
+do { \
+ device_initialize(DEV); \
+ device_set_pm_not_required(DEV); \
+ dev_set_name(DEV, fmt, ##__VA_ARGS__); \
+ DEV->parent = PARENT; \
+ DEV->type = TYPE; \
+ \
+ ret = device_add(DEV); \
+} while (0)
+
+#define CBD_OBJ_HEARTBEAT(OBJ) \
+static void OBJ##_hb_workfn(struct work_struct *work) \
+{ \
+ struct cbd_##OBJ *obj = container_of(work, struct cbd_##OBJ, hb_work.work); \
+ struct cbd_##OBJ##_info *info = obj->OBJ##_info; \
+ \
+ info->alive_ts = ktime_get_real(); \
+ \
+ queue_delayed_work(cbd_wq, &obj->hb_work, CBD_HB_INTERVAL); \
+} \
+ \
+bool cbd_##OBJ##_info_is_alive(struct cbd_##OBJ##_info *info) \
+{ \
+ ktime_t oldest, ts; \
+ \
+ ts = info->alive_ts; \
+ oldest = ktime_sub_ms(ktime_get_real(), CBD_HB_TIMEOUT); \
+ \
+ if (ktime_after(ts, oldest)) \
+ return true; \
+ \
+ return false; \
+} \
+ \
+static ssize_t cbd_##OBJ##_alive_show(struct device *dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+{ \
+ struct cbd_##OBJ##_device *_dev; \
+ \
+ _dev = container_of(dev, struct cbd_##OBJ##_device, dev); \
+ \
+ if (cbd_##OBJ##_info_is_alive(_dev->OBJ##_info)) \
+ return sprintf(buf, "true\n"); \
+ \
+ return sprintf(buf, "false\n"); \
+} \
+ \
+static DEVICE_ATTR(alive, 0400, cbd_##OBJ##_alive_show, NULL)
+
+#endif /* _CBD_INTERNAL_H */
diff --git a/drivers/block/cbd/cbd_transport.c b/drivers/block/cbd/cbd_transport.c
new file mode 100644
index 000000000000..30dc4cd6c77a
--- /dev/null
+++ b/drivers/block/cbd/cbd_transport.c
@@ -0,0 +1,957 @@
+#include <linux/pfn_t.h>
+#include "cbd_internal.h"
+
+#define CBDT_OBJ(OBJ, OBJ_SIZE) \
+extern struct device_type cbd_##OBJ##_type; \
+extern struct device_type cbd_##OBJ##s_type; \
+ \
+static int cbd_##OBJ##s_init(struct cbd_transport *cbdt) \
+{ \
+ struct cbd_##OBJ##s_device *devs; \
+ struct cbd_##OBJ##_device *cbd_dev; \
+ struct device *dev; \
+ int i; \
+ int ret; \
+ \
+ u32 memsize = struct_size(devs, OBJ##_devs, \
+ cbdt->transport_info->OBJ##_num); \
+ devs = kzalloc(memsize, GFP_KERNEL); \
+ if (!devs) { \
+ return -ENOMEM; \
+ } \
+ \
+ dev = &devs->OBJ##s_dev; \
+ device_initialize(dev); \
+ device_set_pm_not_required(dev); \
+ dev_set_name(dev, "cbd_" #OBJ "s"); \
+ dev->parent = &cbdt->device; \
+ dev->type = &cbd_##OBJ##s_type; \
+ ret = device_add(dev); \
+ if (ret) { \
+ goto devs_free; \
+ } \
+ \
+ for (i = 0; i < cbdt->transport_info->OBJ##_num; i++) { \
+ cbd_dev = &devs->OBJ##_devs[i]; \
+ dev = &cbd_dev->dev; \
+ \
+ cbd_dev->cbdt = cbdt; \
+ cbd_dev->OBJ##_info = cbdt_get_##OBJ##_info(cbdt, i); \
+ device_initialize(dev); \
+ device_set_pm_not_required(dev); \
+ dev_set_name(dev, #OBJ "%u", i); \
+ dev->parent = &devs->OBJ##s_dev; \
+ dev->type = &cbd_##OBJ##_type; \
+ \
+ ret = device_add(dev); \
+ if (ret) { \
+ i--; \
+ goto del_device; \
+ } \
+ } \
+ cbdt->cbd_##OBJ##s_dev = devs; \
+ \
+ return 0; \
+del_device: \
+ for (; i >= 0; i--) { \
+ cbd_dev = &devs->OBJ##_devs[i]; \
+ dev = &cbd_dev->dev; \
+ device_del(dev); \
+ } \
+devs_free: \
+ kfree(devs); \
+ return ret; \
+} \
+ \
+static void cbd_##OBJ##s_exit(struct cbd_transport *cbdt) \
+{ \
+ struct cbd_##OBJ##s_device *devs = cbdt->cbd_##OBJ##s_dev; \
+ struct device *dev; \
+ int i; \
+ \
+ if (!devs) \
+ return; \
+ \
+ for (i = 0; i < cbdt->transport_info->OBJ##_num; i++) { \
+ struct cbd_##OBJ##_device *cbd_dev = &devs->OBJ##_devs[i]; \
+ dev = &cbd_dev->dev; \
+ \
+ device_del(dev); \
+ } \
+ \
+ device_del(&devs->OBJ##s_dev); \
+ \
+ kfree(devs); \
+ cbdt->cbd_##OBJ##s_dev = NULL; \
+ \
+ return; \
+} \
+ \
+static inline struct cbd_##OBJ##_info \
+*__get_##OBJ##_info(struct cbd_transport *cbdt, u32 id) \
+{ \
+ struct cbd_transport_info *info = cbdt->transport_info; \
+ void *start = cbdt->transport_info; \
+ \
+ start += info->OBJ##_area_off; \
+ \
+ return start + ((u64)info->OBJ_SIZE * id); \
+} \
+ \
+struct cbd_##OBJ##_info \
+*cbdt_get_##OBJ##_info(struct cbd_transport *cbdt, u32 id) \
+{ \
+ struct cbd_##OBJ##_info *info; \
+ \
+ mutex_lock(&cbdt->lock); \
+ info = __get_##OBJ##_info(cbdt, id); \
+ mutex_unlock(&cbdt->lock); \
+ \
+ return info; \
+} \
+ \
+int cbdt_get_empty_##OBJ##_id(struct cbd_transport *cbdt, u32 *id) \
+{ \
+ struct cbd_transport_info *info = cbdt->transport_info; \
+ struct cbd_##OBJ##_info *_info; \
+ int ret = 0; \
+ int i; \
+ \
+ mutex_lock(&cbdt->lock); \
+ for (i = 0; i < info->OBJ##_num; i++) { \
+ _info = __get_##OBJ##_info(cbdt, i); \
+ if (_info->state == cbd_##OBJ##_state_none) { \
+ cbdt_zero_range(cbdt, _info, info->OBJ_SIZE); \
+ *id = i; \
+ goto out; \
+ } \
+ } \
+ \
+ cbdt_err(cbdt, "No available " #OBJ "_id found."); \
+ ret = -ENOENT; \
+out: \
+ mutex_unlock(&cbdt->lock); \
+ \
+ return ret; \
+}
+
+CBDT_OBJ(host, host_info_size);
+CBDT_OBJ(backend, backend_info_size);
+CBDT_OBJ(blkdev, blkdev_info_size);
+CBDT_OBJ(segment, segment_size);
+
+static struct cbd_transport *cbd_transports[CBD_TRANSPORT_MAX];
+static DEFINE_IDA(cbd_transport_id_ida);
+static DEFINE_MUTEX(cbd_transport_mutex);
+
+extern struct bus_type cbd_bus_type;
+extern struct device cbd_root_dev;
+
+static ssize_t cbd_myhost_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_transport *cbdt;
+ struct cbd_host *host;
+
+ cbdt = container_of(dev, struct cbd_transport, device);
+
+ host = cbdt->host;
+ if (!host)
+ return 0;
+
+ return sprintf(buf, "%d\n", host->host_id);
+}
+
+static DEVICE_ATTR(my_host_id, 0400, cbd_myhost_show, NULL);
+
+enum {
+ CBDT_ADM_OPT_ERR = 0,
+ CBDT_ADM_OPT_OP,
+ CBDT_ADM_OPT_FORCE,
+ CBDT_ADM_OPT_PATH,
+ CBDT_ADM_OPT_BID,
+ CBDT_ADM_OPT_DID,
+ CBDT_ADM_OPT_QUEUES,
+ CBDT_ADM_OPT_HID,
+ CBDT_ADM_OPT_SID,
+ CBDT_ADM_OPT_CACHE_SIZE,
+};
+
+enum {
+ CBDT_ADM_OP_B_START,
+ CBDT_ADM_OP_B_STOP,
+ CBDT_ADM_OP_B_CLEAR,
+ CBDT_ADM_OP_DEV_START,
+ CBDT_ADM_OP_DEV_STOP,
+ CBDT_ADM_OP_DEV_CLEAR,
+ CBDT_ADM_OP_H_CLEAR,
+ CBDT_ADM_OP_S_CLEAR,
+};
+
+static const char *const adm_op_names[] = {
+ [CBDT_ADM_OP_B_START] = "backend-start",
+ [CBDT_ADM_OP_B_STOP] = "backend-stop",
+ [CBDT_ADM_OP_B_CLEAR] = "backend-clear",
+ [CBDT_ADM_OP_DEV_START] = "dev-start",
+ [CBDT_ADM_OP_DEV_STOP] = "dev-stop",
+ [CBDT_ADM_OP_DEV_CLEAR] = "dev-clear",
+ [CBDT_ADM_OP_H_CLEAR] = "host-clear",
+ [CBDT_ADM_OP_S_CLEAR] = "segment-clear",
+};
+
+static const match_table_t adm_opt_tokens = {
+ { CBDT_ADM_OPT_OP, "op=%s" },
+ { CBDT_ADM_OPT_FORCE, "force=%u" },
+ { CBDT_ADM_OPT_PATH, "path=%s" },
+ { CBDT_ADM_OPT_BID, "backend_id=%u" },
+ { CBDT_ADM_OPT_DID, "dev_id=%u" },
+ { CBDT_ADM_OPT_QUEUES, "queues=%u" },
+ { CBDT_ADM_OPT_HID, "host_id=%u" },
+ { CBDT_ADM_OPT_SID, "segment_id=%u" },
+ { CBDT_ADM_OPT_CACHE_SIZE, "cache_size=%u" }, /* unit is MiB */
+ { CBDT_ADM_OPT_ERR, NULL }
+};
+
+
+struct cbd_adm_options {
+ u16 op;
+ u16 force:1;
+ u32 backend_id;
+ union {
+ struct host_options {
+ u32 hid;
+ } host;
+ struct backend_options {
+ char path[CBD_PATH_LEN];
+ u64 cache_size_M;
+ } backend;
+ struct segment_options {
+ u32 sid;
+ } segment;
+ struct blkdev_options {
+ u32 devid;
+ u32 queues;
+ } blkdev;
+ };
+};
+
+static int parse_adm_options(struct cbd_transport *cbdt,
+ char *buf,
+ struct cbd_adm_options *opts)
+{
+ substring_t args[MAX_OPT_ARGS];
+ char *o, *p;
+ int token, ret = 0;
+
+ o = buf;
+
+ while ((p = strsep(&o, ",\n")) != NULL) {
+ if (!*p)
+ continue;
+
+ token = match_token(p, adm_opt_tokens, args);
+ switch (token) {
+ case CBDT_ADM_OPT_OP:
+ ret = match_string(adm_op_names, ARRAY_SIZE(adm_op_names), args[0].from);
+ if (ret < 0) {
+ cbdt_err(cbdt, "unknown op: '%s'\n", args[0].from);
+ ret = -EINVAL;
+ break;
+ }
+ opts->op = ret;
+ break;
+ case CBDT_ADM_OPT_PATH:
+ if (match_strlcpy(opts->backend.path, &args[0],
+ CBD_PATH_LEN) == 0) {
+ ret = -EINVAL;
+ break;
+ }
+ break;
+ case CBDT_ADM_OPT_FORCE:
+ if (match_uint(args, &token) || token != 1) {
+ ret = -EINVAL;
+ goto out;
+ }
+ opts->force = 1;
+ break;
+ case CBDT_ADM_OPT_BID:
+ if (match_uint(args, &token)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ opts->backend_id = token;
+ break;
+ case CBDT_ADM_OPT_DID:
+ if (match_uint(args, &token)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ opts->blkdev.devid = token;
+ break;
+ case CBDT_ADM_OPT_QUEUES:
+ if (match_uint(args, &token)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ opts->blkdev.queues = token;
+ break;
+ case CBDT_ADM_OPT_HID:
+ if (match_uint(args, &token)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ opts->host.hid = token;
+ break;
+ case CBDT_ADM_OPT_SID:
+ if (match_uint(args, &token)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ opts->segment.sid = token;
+ break;
+ case CBDT_ADM_OPT_CACHE_SIZE:
+ if (match_uint(args, &token)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ opts->backend.cache_size_M = token;
+ break;
+ default:
+ cbdt_err(cbdt, "unknown parameter or missing value '%s'\n", p);
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+out:
+ return ret;
+}
+
+void cbdt_zero_range(struct cbd_transport *cbdt, void *pos, u32 size)
+{
+ memset(pos, 0, size);
+}
+
+static void segments_format(struct cbd_transport *cbdt)
+{
+ u32 i;
+ struct cbd_segment_info *seg_info;
+
+ for (i = 0; i < cbdt->transport_info->segment_num; i++) {
+ seg_info = cbdt_get_segment_info(cbdt, i);
+ cbdt_zero_range(cbdt, seg_info, sizeof(struct cbd_segment_info));
+ }
+}
+
+static int cbd_transport_format(struct cbd_transport *cbdt, bool force)
+{
+ struct cbd_transport_info *info = cbdt->transport_info;
+ u64 transport_dev_size;
+ u32 seg_size;
+ u32 nr_segs;
+ u64 magic;
+ u16 flags = 0;
+
+ magic = le64_to_cpu(info->magic);
+ if (magic && !force)
+ return -EEXIST;
+
+ transport_dev_size = bdev_nr_bytes(file_bdev(cbdt->bdev_file));
+ if (transport_dev_size < CBD_TRASNPORT_SIZE_MIN) {
+ cbdt_err(cbdt, "dax device is too small, required at least %u",
+ CBD_TRASNPORT_SIZE_MIN);
+ return -ENOSPC;
+ }
+
+ memset(info, 0, sizeof(*info));
+
+ info->magic = cpu_to_le64(CBD_TRANSPORT_MAGIC);
+ info->version = cpu_to_le16(CBD_TRANSPORT_VERSION);
+#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN)
+ flags |= CBDT_INFO_F_BIGENDIAN;
+#endif
+#ifdef CONFIG_CBD_CRC
+ flags |= CBDT_INFO_F_CRC;
+#endif
+ info->flags = cpu_to_le16(flags);
+
+ info->hosts_registered = 0;
+ /*
+ * Try to fully utilize all available space,
+ * assuming host:blkdev:backend:segment = 1:1:1:1
+ */
+ seg_size = (CBDT_HOST_INFO_SIZE + CBDT_BACKEND_INFO_SIZE +
+ CBDT_BLKDEV_INFO_SIZE + CBDT_SEG_SIZE);
+ nr_segs = (transport_dev_size - CBDT_INFO_SIZE) / seg_size;
+
+ info->host_area_off = CBDT_INFO_OFF + CBDT_INFO_SIZE;
+ info->host_info_size = CBDT_HOST_INFO_SIZE;
+ info->host_num = nr_segs;
+
+ info->backend_area_off = info->host_area_off + (info->host_info_size * info->host_num);
+ info->backend_info_size = CBDT_BACKEND_INFO_SIZE;
+ info->backend_num = nr_segs;
+
+ info->blkdev_area_off = info->backend_area_off + (info->backend_info_size * info->backend_num);
+ info->blkdev_info_size = CBDT_BLKDEV_INFO_SIZE;
+ info->blkdev_num = nr_segs;
+
+ info->segment_area_off = info->blkdev_area_off + (info->blkdev_info_size * info->blkdev_num);
+ info->segment_size = CBDT_SEG_SIZE;
+ info->segment_num = nr_segs;
+
+ cbdt_zero_range(cbdt, (void *)info + info->host_area_off,
+ info->segment_area_off - info->host_area_off);
+
+ segments_format(cbdt);
+
+ return 0;
+}
+
+/*
+ * Any transport metadata allocation or reclaim should be in the
+ * control operation rutine
+ *
+ * All transport space allocation and deallocation should occur within the control flow,
+ * specifically within `adm_store()`, so that all transport space allocation
+ * and deallocation are managed within this function. This prevents other processes
+ * from involving transport space allocation and deallocation. By making `adm_store`
+ * exclusive, we can manage space effectively. For a single-host scenario, `adm_lock`
+ * can ensure mutual exclusion of `adm_store`. However, in a multi-host scenario,
+ * we need a distributed lock to guarantee that all `adm_store` calls are mutually exclusive.
+ *
+ * TODO: Is there a way to lock the CXL shared memory device?
+ */
+static ssize_t adm_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *ubuf,
+ size_t size)
+{
+ int ret;
+ char *buf;
+ struct cbd_adm_options opts = { 0 };
+ struct cbd_transport *cbdt;
+
+ opts.backend_id = U32_MAX;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ cbdt = container_of(dev, struct cbd_transport, device);
+
+ buf = kmemdup(ubuf, size + 1, GFP_KERNEL);
+ if (IS_ERR(buf)) {
+ cbdt_err(cbdt, "failed to dup buf for adm option: %d", (int)PTR_ERR(buf));
+ return PTR_ERR(buf);
+ }
+ buf[size] = '\0';
+ ret = parse_adm_options(cbdt, buf, &opts);
+ if (ret < 0) {
+ kfree(buf);
+ return ret;
+ }
+ kfree(buf);
+
+ mutex_lock(&cbdt->adm_lock);
+ switch (opts.op) {
+ case CBDT_ADM_OP_B_START:
+ u32 cache_segs = 0;
+
+ if (opts.backend.cache_size_M > 0)
+ cache_segs = DIV_ROUND_UP(opts.backend.cache_size_M,
+ cbdt->transport_info->segment_size / CBD_MB);
+
+ ret = cbd_backend_start(cbdt, opts.backend.path, opts.backend_id, cache_segs);
+ break;
+ case CBDT_ADM_OP_B_STOP:
+ ret = cbd_backend_stop(cbdt, opts.backend_id);
+ break;
+ case CBDT_ADM_OP_B_CLEAR:
+ ret = cbd_backend_clear(cbdt, opts.backend_id);
+ break;
+ case CBDT_ADM_OP_DEV_START:
+ if (opts.blkdev.queues > CBD_QUEUES_MAX) {
+ mutex_unlock(&cbdt->adm_lock);
+ cbdt_err(cbdt, "invalid queues = %u, larger than max %u\n",
+ opts.blkdev.queues, CBD_QUEUES_MAX);
+ return -EINVAL;
+ }
+ ret = cbd_blkdev_start(cbdt, opts.backend_id, opts.blkdev.queues);
+ break;
+ case CBDT_ADM_OP_DEV_STOP:
+ ret = cbd_blkdev_stop(cbdt, opts.blkdev.devid, opts.force);
+ break;
+ case CBDT_ADM_OP_DEV_CLEAR:
+ ret = cbd_blkdev_clear(cbdt, opts.blkdev.devid);
+ break;
+ case CBDT_ADM_OP_H_CLEAR:
+ ret = cbd_host_clear(cbdt, opts.host.hid);
+ break;
+ case CBDT_ADM_OP_S_CLEAR:
+ ret = cbd_segment_clear(cbdt, opts.segment.sid);
+ break;
+ default:
+ mutex_unlock(&cbdt->adm_lock);
+ cbdt_err(cbdt, "invalid op: %d\n", opts.op);
+ return -EINVAL;
+ }
+ mutex_unlock(&cbdt->adm_lock);
+
+ if (ret < 0)
+ return ret;
+
+ return size;
+}
+
+static DEVICE_ATTR_WO(adm);
+
+static ssize_t cbd_transport_info(struct cbd_transport *cbdt, char *buf)
+{
+ struct cbd_transport_info *info = cbdt->transport_info;
+ ssize_t ret;
+
+ mutex_lock(&cbdt->lock);
+ info = cbdt->transport_info;
+ mutex_unlock(&cbdt->lock);
+
+ ret = sprintf(buf, "magic: 0x%llx\n"
+ "version: %u\n"
+ "flags: %x\n\n"
+ "hosts_registered: %u\n"
+ "host_area_off: %llu\n"
+ "bytes_per_host_info: %u\n"
+ "host_num: %u\n\n"
+ "backend_area_off: %llu\n"
+ "bytes_per_backend_info: %u\n"
+ "backend_num: %u\n\n"
+ "blkdev_area_off: %llu\n"
+ "bytes_per_blkdev_info: %u\n"
+ "blkdev_num: %u\n\n"
+ "segment_area_off: %llu\n"
+ "bytes_per_segment: %u\n"
+ "segment_num: %u\n",
+ le64_to_cpu(info->magic),
+ le16_to_cpu(info->version),
+ le16_to_cpu(info->flags),
+ info->hosts_registered,
+ info->host_area_off,
+ info->host_info_size,
+ info->host_num,
+ info->backend_area_off,
+ info->backend_info_size,
+ info->backend_num,
+ info->blkdev_area_off,
+ info->blkdev_info_size,
+ info->blkdev_num,
+ info->segment_area_off,
+ info->segment_size,
+ info->segment_num);
+
+ return ret;
+}
+
+static ssize_t cbd_info_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_transport *cbdt;
+
+ cbdt = container_of(dev, struct cbd_transport, device);
+
+ return cbd_transport_info(cbdt, buf);
+}
+static DEVICE_ATTR(info, 0400, cbd_info_show, NULL);
+
+static struct attribute *cbd_transport_attrs[] = {
+ &dev_attr_adm.attr,
+ &dev_attr_info.attr,
+ &dev_attr_my_host_id.attr,
+ NULL
+};
+
+static struct attribute_group cbd_transport_attr_group = {
+ .attrs = cbd_transport_attrs,
+};
+
+static const struct attribute_group *cbd_transport_attr_groups[] = {
+ &cbd_transport_attr_group,
+ NULL
+};
+
+static void cbd_transport_release(struct device *dev)
+{
+}
+
+const struct device_type cbd_transport_type = {
+ .name = "cbd_transport",
+ .groups = cbd_transport_attr_groups,
+ .release = cbd_transport_release,
+};
+
+static int
+cbd_dax_notify_failure(
+ struct dax_device *dax_devp,
+ u64 offset,
+ u64 len,
+ int mf_flags)
+{
+
+ pr_err("%s: dax_devp %llx offset %llx len %lld mf_flags %x\n",
+ __func__, (u64)dax_devp, (u64)offset, (u64)len, mf_flags);
+ return -EOPNOTSUPP;
+}
+
+const struct dax_holder_operations cbd_dax_holder_ops = {
+ .notify_failure = cbd_dax_notify_failure,
+};
+
+static struct cbd_transport *cbdt_alloc(void)
+{
+ struct cbd_transport *cbdt;
+ int ret;
+
+ cbdt = kzalloc(sizeof(struct cbd_transport), GFP_KERNEL);
+ if (!cbdt)
+ return NULL;
+
+ mutex_init(&cbdt->lock);
+ mutex_init(&cbdt->adm_lock);
+ INIT_LIST_HEAD(&cbdt->backends);
+ INIT_LIST_HEAD(&cbdt->devices);
+
+ ret = ida_simple_get(&cbd_transport_id_ida, 0, CBD_TRANSPORT_MAX,
+ GFP_KERNEL);
+ if (ret < 0)
+ goto cbdt_free;
+
+ cbdt->id = ret;
+ cbd_transports[cbdt->id] = cbdt;
+
+ return cbdt;
+
+cbdt_free:
+ kfree(cbdt);
+ return NULL;
+}
+
+static void cbdt_destroy(struct cbd_transport *cbdt)
+{
+ cbd_transports[cbdt->id] = NULL;
+ ida_simple_remove(&cbd_transport_id_ida, cbdt->id);
+ kfree(cbdt);
+}
+
+static int cbdt_dax_init(struct cbd_transport *cbdt, char *path)
+{
+ struct dax_device *dax_dev = NULL;
+ struct file *bdev_file = NULL;
+ long access_size;
+ void *kaddr;
+ u64 start_off = 0;
+ int ret;
+ int id;
+
+ bdev_file = bdev_file_open_by_path(path, BLK_OPEN_READ | BLK_OPEN_WRITE, cbdt, NULL);
+ if (IS_ERR(bdev_file)) {
+ cbdt_err(cbdt, "%s: failed blkdev_get_by_path(%s)\n", __func__, path);
+ ret = PTR_ERR(bdev_file);
+ goto err;
+ }
+
+ dax_dev = fs_dax_get_by_bdev(file_bdev(bdev_file), &start_off,
+ cbdt,
+ &cbd_dax_holder_ops);
+ if (IS_ERR(dax_dev)) {
+ cbdt_err(cbdt, "%s: unable to get daxdev from bdev_file\n", __func__);
+ ret = -ENODEV;
+ goto fput;
+ }
+
+ id = dax_read_lock();
+ access_size = dax_direct_access(dax_dev, 0, 1, DAX_ACCESS, &kaddr, NULL);
+ if (access_size != 1) {
+ dax_read_unlock(id);
+ ret = -EINVAL;
+ goto dax_put;
+ }
+
+ cbdt->bdev_file = bdev_file;
+ cbdt->dax_dev = dax_dev;
+ cbdt->transport_info = (struct cbd_transport_info *)kaddr;
+ dax_read_unlock(id);
+
+ return 0;
+
+dax_put:
+ fs_put_dax(dax_dev, cbdt);
+fput:
+ fput(bdev_file);
+err:
+ return ret;
+}
+
+static void cbdt_dax_release(struct cbd_transport *cbdt)
+{
+ if (cbdt->dax_dev)
+ fs_put_dax(cbdt->dax_dev, cbdt);
+
+ if (cbdt->bdev_file)
+ fput(cbdt->bdev_file);
+}
+
+static int cbd_transport_init(struct cbd_transport *cbdt)
+{
+ struct device *dev;
+
+ dev = &cbdt->device;
+ device_initialize(dev);
+ device_set_pm_not_required(dev);
+ dev->bus = &cbd_bus_type;
+ dev->type = &cbd_transport_type;
+ dev->parent = &cbd_root_dev;
+
+ dev_set_name(&cbdt->device, "transport%d", cbdt->id);
+
+ return device_add(&cbdt->device);
+}
+
+
+static int cbdt_validate(struct cbd_transport *cbdt)
+{
+ u16 flags;
+
+ if (le64_to_cpu(cbdt->transport_info->magic) != CBD_TRANSPORT_MAGIC) {
+ cbdt_err(cbdt, "unexpected magic: %llx\n",
+ le64_to_cpu(cbdt->transport_info->magic));
+ return -EINVAL;
+ }
+
+ flags = le16_to_cpu(cbdt->transport_info->flags);
+#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN)
+ if (!(flags & CBDT_INFO_F_BIGENDIAN)) {
+ cbdt_err(cbdt, "transport is not big endian\n");
+ return -EINVAL;
+ }
+#else
+ if (flags & CBDT_INFO_F_BIGENDIAN) {
+ cbdt_err(cbdt, "transport is big endian\n");
+ return -EINVAL;
+ }
+#endif
+
+#ifndef CONFIG_CBD_CRC
+ if (flags & CBDT_INFO_F_CRC) {
+ cbdt_err(cbdt, "transport expects CBD_CRC enabled.\n");
+ return -ENOTSUPP;
+ }
+#endif
+
+ return 0;
+}
+
+int cbdt_unregister(u32 tid)
+{
+ struct cbd_transport *cbdt;
+
+ cbdt = cbd_transports[tid];
+ if (!cbdt) {
+ pr_err("tid: %u, is not registered\n", tid);
+ return -EINVAL;
+ }
+
+ mutex_lock(&cbdt->lock);
+ if (!list_empty(&cbdt->backends) || !list_empty(&cbdt->devices)) {
+ mutex_unlock(&cbdt->lock);
+ return -EBUSY;
+ }
+ mutex_unlock(&cbdt->lock);
+
+ cbd_blkdevs_exit(cbdt);
+ cbd_segments_exit(cbdt);
+ cbd_backends_exit(cbdt);
+ cbd_hosts_exit(cbdt);
+
+ cbd_host_unregister(cbdt);
+ cbdt->transport_info->hosts_registered--;
+
+ device_unregister(&cbdt->device);
+ cbdt_dax_release(cbdt);
+ cbdt_destroy(cbdt);
+ module_put(THIS_MODULE);
+
+ return 0;
+}
+
+static bool cbdt_register_allowed(struct cbd_transport *cbdt)
+{
+ struct cbd_transport_info *transport_info;
+
+ transport_info = cbdt->transport_info;
+
+ if (transport_info->hosts_registered >= CBDT_HOSTS_MAX) {
+ cbdt_err(cbdt, "too many hosts registered: %u (max %u).",
+ transport_info->hosts_registered,
+ CBDT_HOSTS_MAX);
+ return false;
+ }
+
+ return true;
+}
+
+int cbdt_register(struct cbdt_register_options *opts)
+{
+ struct cbd_transport *cbdt;
+ int ret;
+
+ if (!try_module_get(THIS_MODULE))
+ return -ENODEV;
+
+ if (!strstr(opts->path, "/dev/pmem")) {
+ pr_err("%s: path (%s) is not pmem\n",
+ __func__, opts->path);
+ ret = -EINVAL;
+ goto module_put;
+ }
+
+ cbdt = cbdt_alloc();
+ if (!cbdt) {
+ ret = -ENOMEM;
+ goto module_put;
+ }
+
+ ret = cbdt_dax_init(cbdt, opts->path);
+ if (ret)
+ goto cbdt_destroy;
+
+ if (!cbdt_register_allowed(cbdt)) {
+ ret = -EINVAL;
+ goto dax_release;
+ }
+
+ if (opts->format) {
+ ret = cbd_transport_format(cbdt, opts->force);
+ if (ret < 0)
+ goto dax_release;
+ }
+
+ ret = cbdt_validate(cbdt);
+ if (ret)
+ goto dax_release;
+
+ ret = cbd_transport_init(cbdt);
+ if (ret)
+ goto dax_release;
+
+ ret = cbd_host_register(cbdt, opts->hostname);
+ if (ret)
+ goto dev_unregister;
+
+ if (cbd_hosts_init(cbdt) || cbd_backends_init(cbdt) ||
+ cbd_segments_init(cbdt) || cbd_blkdevs_init(cbdt)) {
+ ret = -ENOMEM;
+ goto devs_exit;
+ }
+
+ cbdt->transport_info->hosts_registered++;
+
+ return 0;
+
+devs_exit:
+ cbd_blkdevs_exit(cbdt);
+ cbd_segments_exit(cbdt);
+ cbd_backends_exit(cbdt);
+ cbd_hosts_exit(cbdt);
+
+ cbd_host_unregister(cbdt);
+dev_unregister:
+ device_unregister(&cbdt->device);
+dax_release:
+ cbdt_dax_release(cbdt);
+cbdt_destroy:
+ cbdt_destroy(cbdt);
+module_put:
+ module_put(THIS_MODULE);
+
+ return ret;
+}
+
+void cbdt_add_backend(struct cbd_transport *cbdt, struct cbd_backend *cbdb)
+{
+ mutex_lock(&cbdt->lock);
+ list_add(&cbdb->node, &cbdt->backends);
+ mutex_unlock(&cbdt->lock);
+}
+
+void cbdt_del_backend(struct cbd_transport *cbdt, struct cbd_backend *cbdb)
+{
+ if (list_empty(&cbdb->node))
+ return;
+
+ mutex_lock(&cbdt->lock);
+ list_del_init(&cbdb->node);
+ mutex_unlock(&cbdt->lock);
+}
+
+struct cbd_backend *cbdt_get_backend(struct cbd_transport *cbdt, u32 id)
+{
+ struct cbd_backend *backend;
+
+ mutex_lock(&cbdt->lock);
+ list_for_each_entry(backend, &cbdt->backends, node) {
+ if (backend->backend_id == id)
+ goto out;
+ }
+ backend = NULL;
+out:
+ mutex_unlock(&cbdt->lock);
+ return backend;
+}
+
+void cbdt_add_blkdev(struct cbd_transport *cbdt, struct cbd_blkdev *blkdev)
+{
+ mutex_lock(&cbdt->lock);
+ list_add(&blkdev->node, &cbdt->devices);
+ mutex_unlock(&cbdt->lock);
+}
+
+void cbdt_del_blkdev(struct cbd_transport *cbdt, struct cbd_blkdev *blkdev)
+{
+ if (list_empty(&blkdev->node))
+ return;
+
+ mutex_lock(&cbdt->lock);
+ list_del_init(&blkdev->node);
+ mutex_unlock(&cbdt->lock);
+}
+
+struct cbd_blkdev *cbdt_get_blkdev(struct cbd_transport *cbdt, u32 id)
+{
+ struct cbd_blkdev *dev;
+
+ mutex_lock(&cbdt->lock);
+ list_for_each_entry(dev, &cbdt->devices, node) {
+ if (dev->blkdev_id == id)
+ goto out;
+ }
+ dev = NULL;
+out:
+ mutex_unlock(&cbdt->lock);
+ return dev;
+}
+
+struct page *cbdt_page(struct cbd_transport *cbdt, u64 transport_off, u32 *page_off)
+{
+ long access_size;
+ pfn_t pfn;
+
+ access_size = dax_direct_access(cbdt->dax_dev, transport_off >> PAGE_SHIFT,
+ 1, DAX_ACCESS, NULL, &pfn);
+ if (access_size < 0)
+ return NULL;
+
+ if (page_off)
+ *page_off = transport_off & PAGE_MASK;
+
+ return pfn_t_to_page(pfn);
+}
--
2.34.1
