/*
* Split the bio into several clones.
*/
static void __split_bio(struct mapped_device *md, struct bio *bio)
{
struct clone_info ci;
ci.map = dm_get_table(md);
if (!ci.map) {
bio_io_error(bio, bio->bi_size);
return;
}
ci.md = md;
ci.bio = bio;
ci.io = alloc_io(md);
ci.io->error = 0;
atomic_set(&ci.io->io_count, 1);
ci.io->bio = bio;
ci.io->md = md;
ci.sector = bio->bi_sector;
ci.sector_count = bio_sectors(bio);
ci.idx = bio->bi_idx;
atomic_inc(&md->pending);
while (ci.sector_count)
__clone_and_map(&ci);
/* drop the extra reference count */
dec_pending(ci.io, 0);
dm_table_put(ci.map);
}
/**ltl
* 功能: 分割bio请求
* 参数:
* 返回值:
* 说明:
*/
static void __split_bio(struct mapped_device *md, struct bio *bio)
{
struct clone_info ci;
ci.map = dm_get_table(md);
if (!ci.map) {
bio_io_error(bio, bio->bi_size);
return;
}
ci.md = md;
ci.bio = bio;
ci.io = alloc_io(md);
ci.io->error = 0;
atomic_set(&ci.io->io_count, 1);
ci.io->bio = bio;
ci.io->md = md;
ci.sector = bio->bi_sector; /* 请求起始扇区 */
/* 从这里可以看出数据长度必定是512的整数倍 */
ci.sector_count = bio_sectors(bio); /* 数据长度(扇区数) */
ci.idx = bio->bi_idx; /* 当前bi_vec数组下标 */
start_io_acct(ci.io);
while (ci.sector_count) /* 分发各个请求 */
__clone_and_map(&ci);
/* drop the extra reference count */
dec_pending(ci.io, 0);
dm_table_put(ci.map);
}
static struct io* wake_up_next_iothread(struct pfiled *pfiled)
{
struct io *io = alloc_io(pfiled);
if (io){
pthread_mutex_lock(&io->lock);
pthread_cond_signal(&io->cond);
pthread_mutex_unlock(&io->lock);
}
return io;
}
