new file mode 100644
@@ -0,0 +1,349 @@
+#include "cbd_internal.h"
+
+static ssize_t cbd_seg_detail_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_segment_device *segment;
+ struct cbd_segment_info *segment_info;
+
+ segment = container_of(dev, struct cbd_segment_device, dev);
+ segment_info = segment->segment_info;
+
+ if (segment_info->state == cbd_segment_state_none)
+ return 0;
+
+ if (segment_info->type == cbds_type_channel)
+ return cbd_channel_seg_detail_show((struct cbd_channel_info *)segment_info, buf);
+
+ return 0;
+}
+
+static ssize_t cbd_seg_type_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cbd_segment_device *segment;
+ struct cbd_segment_info *segment_info;
+
+ segment = container_of(dev, struct cbd_segment_device, dev);
+ segment_info = segment->segment_info;
+
+ if (segment_info->state == cbd_segment_state_none)
+ return 0;
+
+ return sprintf(buf, "%s\n", cbds_type_str(segment_info->type));
+}
+
+static DEVICE_ATTR(detail, 0400, cbd_seg_detail_show, NULL);
+static DEVICE_ATTR(type, 0400, cbd_seg_type_show, NULL);
+
+CBD_OBJ_HEARTBEAT(segment);
+
+static struct attribute *cbd_segment_attrs[] = {
+ &dev_attr_detail.attr,
+ &dev_attr_type.attr,
+ &dev_attr_alive.attr,
+ NULL
+};
+
+static struct attribute_group cbd_segment_attr_group = {
+ .attrs = cbd_segment_attrs,
+};
+
+static const struct attribute_group *cbd_segment_attr_groups[] = {
+ &cbd_segment_attr_group,
+ NULL
+};
+
+static void cbd_segment_release(struct device *dev)
+{
+}
+
+const struct device_type cbd_segment_type = {
+ .name = "cbd_segment",
+ .groups = cbd_segment_attr_groups,
+ .release = cbd_segment_release,
+};
+
+const struct device_type cbd_segments_type = {
+ .name = "cbd_segments",
+ .release = cbd_segment_release,
+};
+
+void cbd_segment_init(struct cbd_transport *cbdt, struct cbd_segment *segment,
+ struct cbds_init_options *options)
+{
+ struct cbd_segment_info *segment_info = cbdt_get_segment_info(cbdt, options->seg_id);
+
+ segment->cbdt = cbdt;
+ segment->segment_info = segment_info;
+ segment->seg_id = options->seg_id;
+ segment_info->type = options->type;
+ segment->seg_ops = options->seg_ops;
+ segment->data_size = CBDT_SEG_SIZE - options->data_off;
+ segment->data = (void *)(segment->segment_info) + options->data_off;
+ segment->priv_data = options->priv_data;
+
+ segment_info->ref++;
+ segment_info->state = cbd_segment_state_running;
+
+ INIT_DELAYED_WORK(&segment->hb_work, segment_hb_workfn);
+ queue_delayed_work(cbd_wq, &segment->hb_work, 0);
+}
+
+void cbd_segment_exit(struct cbd_segment *segment)
+{
+ if (!segment->segment_info ||
+ segment->segment_info->state != cbd_segment_state_running)
+ return;
+
+ cancel_delayed_work_sync(&segment->hb_work);
+
+ if (--segment->segment_info->ref > 0)
+ return;
+
+ segment->segment_info->state = cbd_segment_state_none;
+ segment->segment_info->alive_ts = 0;
+}
+
+int cbd_segment_clear(struct cbd_transport *cbdt, u32 seg_id)
+{
+ struct cbd_segment_info *segment_info;
+
+ segment_info = cbdt_get_segment_info(cbdt, seg_id);
+ if (cbd_segment_info_is_alive(segment_info)) {
+ cbdt_err(cbdt, "segment %u is still alive\n", seg_id);
+ return -EBUSY;
+ }
+
+ cbdt_zero_range(cbdt, segment_info, CBDT_SEG_SIZE);
+
+ return 0;
+}
+
+void cbds_copy_data(struct cbd_seg_pos *dst_pos,
+ struct cbd_seg_pos *src_pos, u32 len)
+{
+ u32 copied = 0;
+ u32 to_copy;
+
+ while (copied < len) {
+ if (dst_pos->off >= dst_pos->segment->data_size)
+ dst_pos->segment->seg_ops->sanitize_pos(dst_pos);
+
+ if (src_pos->off >= src_pos->segment->data_size)
+ src_pos->segment->seg_ops->sanitize_pos(src_pos);
+
+ to_copy = len - copied;
+
+ if (to_copy > dst_pos->segment->data_size - dst_pos->off)
+ to_copy = dst_pos->segment->data_size - dst_pos->off;
+
+ if (to_copy > src_pos->segment->data_size - src_pos->off)
+ to_copy = src_pos->segment->data_size - src_pos->off;
+
+ memcpy(dst_pos->segment->data + dst_pos->off, src_pos->segment->data + src_pos->off, to_copy);
+
+ copied += to_copy;
+
+ cbds_pos_advance(dst_pos, to_copy);
+ cbds_pos_advance(src_pos, to_copy);
+ }
+}
+
+void cbds_copy_to_bio(struct cbd_segment *segment,
+ u32 data_off, u32 data_len, struct bio *bio, u32 bio_off)
+{
+ struct bio_vec bv;
+ struct bvec_iter iter;
+ void *dst;
+ u32 to_copy, page_off = 0;
+ struct cbd_seg_pos pos = { .segment = segment,
+ .off = data_off };
+
+next:
+ bio_for_each_segment(bv, bio, iter) {
+ if (bio_off > bv.bv_len) {
+ bio_off -= bv.bv_len;
+ continue;
+ }
+ page_off = bv.bv_offset;
+ page_off += bio_off;
+ bio_off = 0;
+
+ dst = kmap_local_page(bv.bv_page);
+again:
+ if (pos.off >= pos.segment->data_size)
+ segment->seg_ops->sanitize_pos(&pos);
+ segment = pos.segment;
+
+ to_copy = min(bv.bv_offset + bv.bv_len - page_off,
+ segment->data_size - pos.off);
+ if (to_copy > data_len)
+ to_copy = data_len;
+ flush_dcache_page(bv.bv_page);
+ memcpy(dst + page_off, segment->data + pos.off, to_copy);
+
+ /* advance */
+ pos.off += to_copy;
+ page_off += to_copy;
+ data_len -= to_copy;
+ if (!data_len) {
+ kunmap_local(dst);
+ return;
+ }
+
+ /* more data in this bv page */
+ if (page_off < bv.bv_offset + bv.bv_len)
+ goto again;
+ kunmap_local(dst);
+ }
+
+ if (bio->bi_next) {
+ bio = bio->bi_next;
+ goto next;
+ }
+}
+
+void cbds_copy_from_bio(struct cbd_segment *segment,
+ u32 data_off, u32 data_len, struct bio *bio, u32 bio_off)
+{
+ struct bio_vec bv;
+ struct bvec_iter iter;
+ void *src;
+ u32 to_copy, page_off = 0;
+ struct cbd_seg_pos pos = { .segment = segment,
+ .off = data_off };
+
+next:
+ bio_for_each_segment(bv, bio, iter) {
+ if (bio_off > bv.bv_len) {
+ bio_off -= bv.bv_len;
+ continue;
+ }
+ page_off = bv.bv_offset;
+ page_off += bio_off;
+ bio_off = 0;
+
+ src = kmap_local_page(bv.bv_page);
+again:
+ if (pos.off >= pos.segment->data_size)
+ segment->seg_ops->sanitize_pos(&pos);
+ segment = pos.segment;
+
+ to_copy = min(bv.bv_offset + bv.bv_len - page_off,
+ segment->data_size - pos.off);
+ if (to_copy > data_len)
+ to_copy = data_len;
+
+ memcpy(segment->data + pos.off, src + page_off, to_copy);
+ flush_dcache_page(bv.bv_page);
+
+ /* advance */
+ pos.off += to_copy;
+ page_off += to_copy;
+ data_len -= to_copy;
+ if (!data_len) {
+ kunmap_local(src);
+ return;
+ }
+
+ /* more data in this bv page */
+ if (page_off < bv.bv_offset + bv.bv_len)
+ goto again;
+ kunmap_local(src);
+ }
+
+ if (bio->bi_next) {
+ bio = bio->bi_next;
+ goto next;
+ }
+}
+
+u32 cbd_seg_crc(struct cbd_segment *segment, u32 data_off, u32 data_len)
+{
+ u32 crc = 0;
+ u32 crc_size;
+ struct cbd_seg_pos pos = { .segment = segment,
+ .off = data_off };
+
+ while (data_len) {
+ if (pos.off >= pos.segment->data_size)
+ segment->seg_ops->sanitize_pos(&pos);
+ segment = pos.segment;
+
+ crc_size = min(segment->data_size - pos.off, data_len);
+
+ crc = crc32(crc, segment->data + pos.off, crc_size);
+
+ data_len -= crc_size;
+ pos.off += crc_size;
+ }
+
+ return crc;
+}
+
+int cbds_map_pages(struct cbd_segment *segment, struct cbd_backend_io *io)
+{
+ struct cbd_transport *cbdt = segment->cbdt;
+ struct cbd_se *se = io->se;
+ u32 off = se->data_off;
+ u32 size = se->data_len;
+ u32 done = 0;
+ struct page *page;
+ u32 page_off;
+ int ret = 0;
+ int id;
+
+ id = dax_read_lock();
+ while (size) {
+ unsigned int len = min_t(size_t, PAGE_SIZE, size);
+ struct cbd_seg_pos pos = { .segment = segment,
+ .off = off + done };
+
+ if (pos.off >= pos.segment->data_size)
+ segment->seg_ops->sanitize_pos(&pos);
+ segment = pos.segment;
+
+ u64 transport_off = segment->data -
+ (void *)cbdt->transport_info + pos.off;
+
+ page = cbdt_page(cbdt, transport_off, &page_off);
+
+ ret = bio_add_page(io->bio, page, len, 0);
+ if (unlikely(ret != len)) {
+ cbdt_err(cbdt, "failed to add page");
+ goto out;
+ }
+
+ done += len;
+ size -= len;
+ }
+
+ ret = 0;
+out:
+ dax_read_unlock(id);
+ return ret;
+}
+
+int cbds_pos_advance(struct cbd_seg_pos *seg_pos, u32 len)
+{
+ u32 to_advance;
+
+ while (len) {
+ to_advance = len;
+
+ if (seg_pos->off >= seg_pos->segment->data_size)
+ seg_pos->segment->seg_ops->sanitize_pos(seg_pos);
+
+ if (to_advance > seg_pos->segment->data_size - seg_pos->off)
+ to_advance = seg_pos->segment->data_size - seg_pos->off;
+
+ seg_pos->off += to_advance;
+
+ len -= to_advance;
+ }
+
+ return 0;
+}
The `cbd_segments` is an abstraction of the data area in transport. The data area in transport is divided into segments. The specific use of this area is determined by `cbd_seg_type`. For example, `cbd_blkdev` and `cbd_backend` data transfers need to access a segment of the type `cbds_type_channel`. The segment also allows for more scenarios and more segment types to be expanded. Signed-off-by: Dongsheng Yang <dongsheng.yang@linux.dev> --- drivers/block/cbd/cbd_segment.c | 349 ++++++++++++++++++++++++++++++++ 1 file changed, 349 insertions(+) create mode 100644 drivers/block/cbd/cbd_segment.c