From: Dongsheng Yang <dongsheng.yang.linux@xxxxxxxxx>
cbd_transport represents the layout of the entire shared memory, as shown below.
┌───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ cbd transport │
├────────────────────┬───────────────────────┬───────────────────────┬──────────────────────┬───────────────────────────────────┤
│ │ hosts │ backends │ blkdevs │ channels │
│ cbd transport info ├────┬────┬────┬────────┼────┬────┬────┬────────┼────┬────┬────┬───────┼───────┬───────┬───────┬───────────┤
│ │ │ │ │ ... │ │ │ │ ... │ │ │ │ ... │ │ │ │ ... │
└────────────────────┴────┴────┴────┴────────┴────┴────┴────┴────────┴────┴────┴────┴───────┴───┬───┴───────┴───────┴───────────┘
│
│
│
│
┌─────────────────────────────────────────────────────────────────────────────────────┘
│
│
▼
┌───────────────────────────────────────────────────────────┐
│ channel │
├────────────────────┬──────────────────────────────────────┤
│ channel meta │ channel data │
└─────────┬──────────┴────────────────────────────────-─────┘
│
│
│
▼
┌──────────────────────────────────────────────────────────┐
│ channel meta │
├───────────┬──────────────┬───────────────────────────────┤
│ meta ctrl │ comp ring │ cmd ring │
└───────────┴──────────────┴───────────────────────────────┘
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) Channels:
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:
Channel is further divided into meta and data regions.
The meta region includes cmd rings and comp rings.
The blkdev converts upper-layer requests into cbd_se and fills
them into the cmd ring. The handler accepts the cbd_se from
the cmd 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.
Signed-off-by: Dongsheng Yang <dongsheng.yang.linux@xxxxxxxxx>
---
drivers/block/cbd/Makefile | 2 +-
drivers/block/cbd/cbd_main.c | 8 +
drivers/block/cbd/cbd_transport.c | 721 ++++++++++++++++++++++++++++++
3 files changed, 730 insertions(+), 1 deletion(-)
create mode 100644 drivers/block/cbd/cbd_transport.c
diff --git a/drivers/block/cbd/Makefile b/drivers/block/cbd/Makefile
index 2765325486a2..a22796bfa7db 100644
--- a/drivers/block/cbd/Makefile
+++ b/drivers/block/cbd/Makefile
@@ -1,3 +1,3 @@
-cbd-y := cbd_main.o
+cbd-y := cbd_main.o cbd_transport.o
obj-$(CONFIG_BLK_DEV_CBD) += cbd.o
diff --git a/drivers/block/cbd/cbd_main.c b/drivers/block/cbd/cbd_main.c
index 0a87c95d749d..8cfa60dde7c5 100644
--- a/drivers/block/cbd/cbd_main.c
+++ b/drivers/block/cbd/cbd_main.c
@@ -109,6 +109,10 @@ static ssize_t transport_unregister_store(const struct bus_type *bus, const char
return -EINVAL;
}
+ ret = cbdt_unregister(transport_id);
+ if (ret < 0)
+ return ret;
+
return size;
}
@@ -136,6 +140,10 @@ static ssize_t transport_register_store(const struct bus_type *bus, const char *
}
kfree(buf);
+ ret = cbdt_register(&opts);
+ if (ret < 0)
+ return ret;
+
return size;
}
diff --git a/drivers/block/cbd/cbd_transport.c b/drivers/block/cbd/cbd_transport.c
new file mode 100644
index 000000000000..3a4887afab08
--- /dev/null
+++ b/drivers/block/cbd/cbd_transport.c
@@ -0,0 +1,721 @@
+#include <linux/pfn_t.h>
+
+#include "cbd_internal.h"
+
+#define CBDT_OBJ(OBJ, OBJ_SIZE) \
+ \
+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 + (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); \
+ cbdt_flush_range(cbdt, _info, sizeof(*_info)); \
+ if (_info->state == cbd_##OBJ##_state_none) { \
+ *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(channel, channel_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,
+};
+
+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,
+};
+
+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",
+};
+
+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, "devid=%u" },
+ { CBDT_ADM_OPT_QUEUES, "queues=%u" },
+ { 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];
+ } backend;
+ struct channel_options {
+ u32 cid;
+ } channel;
+ 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) {
+ pr_err("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;
+ default:
+ pr_err("unknown parameter or missing value '%s'\n", p);
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+out:
+ return ret;
+}
+
+static void transport_zero_range(struct cbd_transport *cbdt, void *pos, u64 size)
+{
+ memset(pos, 0, size);
+ cbdt_flush_range(cbdt, pos, size);
+}
+
+static void channels_format(struct cbd_transport *cbdt)
+{
+ struct cbd_transport_info *info = cbdt->transport_info;
+ struct cbd_channel_info *channel_info;
+ int i;
+
+ for (i = 0; i < info->channel_num; i++) {
+ channel_info = __get_channel_info(cbdt, i);
+ transport_zero_range(cbdt, channel_info, CBDC_META_SIZE);
+ }
+}
+
+static int cbd_transport_format(struct cbd_transport *cbdt, bool force)
+{
+ struct cbd_transport_info *info = cbdt->transport_info;
+ u64 magic;
+
+ magic = le64_to_cpu(info->magic);
+ if (magic && !force) {
+ return -EEXIST;
+ }
+
+ /* TODO make these configureable */
+ info->magic = cpu_to_le64(CBD_TRANSPORT_MAGIC);
+ info->version = cpu_to_le16(CBD_TRANSPORT_VERSION);
+#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __GIT_ENDIAN : defined(__BIG_ENDIAN)
+ info->flags = cpu_to_le16(CBDT_INFO_F_BIGENDIAN);
+#endif
+ info->host_area_off = CBDT_HOST_AREA_OFF;
+ info->host_info_size = CBDT_HOST_INFO_SIZE;
+ info->host_num = CBDT_HOST_NUM;
+
+ info->backend_area_off = CBDT_BACKEND_AREA_OFF;
+ info->backend_info_size = CBDT_BACKEND_INFO_SIZE;
+ info->backend_num = CBDT_BACKEND_NUM;
+
+ info->blkdev_area_off = CBDT_BLKDEV_AREA_OFF;
+ info->blkdev_info_size = CBDT_BLKDEV_INFO_SIZE;
+ info->blkdev_num = CBDT_BLKDEV_NUM;
+
+ info->channel_area_off = CBDT_CHANNEL_AREA_OFF;
+ info->channel_size = CBDT_CHANNEL_SIZE;
+ info->channel_num = CBDT_CHANNEL_NUM;
+
+ cbdt_flush_range(cbdt, info, sizeof(*info));
+
+ transport_zero_range(cbdt, (void *)info + info->host_area_off,
+ info->channel_area_off - info->host_area_off);
+
+ channels_format(cbdt);
+
+ return 0;
+}
+
+
+
+static ssize_t cbd_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;
+
+ 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)) {
+ pr_err("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);
+
+ switch (opts.op) {
+ case CBDT_ADM_OP_B_START:
+ break;
+ case CBDT_ADM_OP_B_STOP:
+ break;
+ case CBDT_ADM_OP_B_CLEAR:
+ break;
+ case CBDT_ADM_OP_DEV_START:
+ break;
+ case CBDT_ADM_OP_DEV_STOP:
+ break;
+ default:
+ pr_err("invalid op: %d\n", opts.op);
+ return -EINVAL;
+ }
+
+ if (ret < 0)
+ return ret;
+
+ return size;
+}
+
+static DEVICE_ATTR(adm, 0200, NULL, cbd_adm_store);
+
+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" \
+ "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" \
+ "channel_area_off: %llu\n" \
+ "bytes_per_channel: %u\n" \
+ "channel_num: %u\n",
+ le64_to_cpu(info->magic),
+ le16_to_cpu(info->version),
+ le16_to_cpu(info->flags),
+ 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->channel_area_off,
+ info->channel_size,
+ info->channel_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)
+{
+}
+
+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;
+ }
+
+ 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 bdev_handle *handle = NULL;
+ long access_size;
+ void *kaddr;
+ u64 nr_pages = CBD_TRASNPORT_SIZE >> PAGE_SHIFT;
+ u64 start_off = 0;
+ int ret;
+
+ handle = bdev_open_by_path(path, BLK_OPEN_READ | BLK_OPEN_WRITE, cbdt, NULL);
+ if (IS_ERR(handle)) {
+ pr_err("%s: failed blkdev_get_by_path(%s)\n", __func__, path);
+ ret = PTR_ERR(handle);
+ goto err;
+ }
+
+ dax_dev = fs_dax_get_by_bdev(handle->bdev, &start_off,
+ cbdt,
+ &cbd_dax_holder_ops);
+ if (IS_ERR(dax_dev)) {
+ pr_err("%s: unable to get daxdev from handle->bdev\n", __func__);
+ ret = -ENODEV;
+ goto bdev_release;
+ }
+
+ access_size = dax_direct_access(dax_dev, 0, nr_pages, DAX_ACCESS, &kaddr, NULL);
+ if (access_size != nr_pages) {
+ ret = -EINVAL;
+ goto dax_put;
+ }
+
+ cbdt->bdev_handle = handle;
+ cbdt->dax_dev = dax_dev;
+ cbdt->transport_info = (struct cbd_transport_info *)kaddr;
+
+ return 0;
+
+dax_put:
+ fs_put_dax(dax_dev, cbdt);
+bdev_release:
+ bdev_release(handle);
+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_handle)
+ bdev_release(cbdt->bdev_handle);
+}
+
+static int cbd_transport_init(struct cbd_transport *cbdt)
+{
+ struct device *dev;
+
+ mutex_init(&cbdt->lock);
+ INIT_LIST_HEAD(&cbdt->backends);
+ INIT_LIST_HEAD(&cbdt->devices);
+
+ 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) {
+ return -EINVAL;
+ }
+
+ flags = le16_to_cpu(cbdt->transport_info->flags);
+#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __GIT_ENDIAN : defined(__BIG_ENDIAN)
+ if (!(flags & CBDT_INFO_F_BIGENDIAN)) {
+ return -EINVAL;
+ }
+#else
+ if ((flags & CBDT_INFO_F_BIGENDIAN)) {
+ return -EINVAL;
+ }
+#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);
+
+ device_unregister(&cbdt->device);
+ cbdt_dax_release(cbdt);
+ cbdt_destroy(cbdt);
+ module_put(THIS_MODULE);
+
+ return 0;
+}
+
+
+int cbdt_register(struct cbdt_register_options *opts)
+{
+ struct cbd_transport *cbdt;
+ int ret;
+
+ if (!try_module_get(THIS_MODULE))
+ return -ENODEV;
+
+ /* TODO support /dev/dax */
+ 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 (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;
+ }
+
+ return 0;
+
+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);
+}
+
+struct cbd_blkdev *cbdt_fetch_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) {
+ list_del(&dev->node);
+ goto out;
+ }
+ }
+ dev = NULL;
+out:
+ mutex_unlock(&cbdt->lock);
+ return dev;
+}
+
+struct page *cbdt_page(struct cbd_transport *cbdt, u64 transport_off)
+{
+ long access_size;
+ pfn_t pfn;
+
+ access_size = dax_direct_access(cbdt->dax_dev, transport_off >> PAGE_SHIFT, 1, DAX_ACCESS, NULL, &pfn);
+
+ return pfn_t_to_page(pfn);
+}
+
+void cbdt_flush_range(struct cbd_transport *cbdt, void *pos, u64 size)
+{
+ u64 offset = pos - (void *)cbdt->transport_info;
+ u32 off_in_page = (offset & CBD_PAGE_MASK);
+
+ offset -= off_in_page;
+ size = round_up(off_in_page + size, PAGE_SIZE);
+
+ while (size) {
+ flush_dcache_page(cbdt_page(cbdt, offset));
+ offset += PAGE_SIZE;
+ size -= PAGE_SIZE;
+ }
+}
--
2.34.1
