static int btt_write_pg()

in btt.c [1311:1424]

• 90 lines of code
• 21 McCabe index (conditional complexity)

static int btt_write_pg(struct btt *btt, struct bio_integrity_payload *bip,
			sector_t sector, struct page *page, unsigned int off,
			unsigned int len)
{
	int ret = 0;
	struct arena_info *arena = NULL;
	u32 premap = 0, old_postmap, new_postmap, lane = 0, i;
	struct log_entry log;
	int sub;

	while (len) {
		u32 cur_len;
		int e_flag;

 retry:
		lane = nd_region_acquire_lane(btt->nd_region);

		ret = lba_to_arena(btt, sector, &premap, &arena);
		if (ret)
			goto out_lane;
		cur_len = min(btt->sector_size, len);

		if ((arena->flags & IB_FLAG_ERROR_MASK) != 0) {
			ret = -EIO;
			goto out_lane;
		}

		if (btt_is_badblock(btt, arena, arena->freelist[lane].block))
			arena->freelist[lane].has_err = 1;

		if (mutex_is_locked(&arena->err_lock)
				|| arena->freelist[lane].has_err) {
			nd_region_release_lane(btt->nd_region, lane);

			ret = arena_clear_freelist_error(arena, lane);
			if (ret)
				return ret;

			/* OK to acquire a different lane/free block */
			goto retry;
		}

		new_postmap = arena->freelist[lane].block;

		/* Wait if the new block is being read from */
		for (i = 0; i < arena->nfree; i++)
			while (arena->rtt[i] == (RTT_VALID | new_postmap))
				cpu_relax();


		if (new_postmap >= arena->internal_nlba) {
			ret = -EIO;
			goto out_lane;
		}

		ret = btt_data_write(arena, new_postmap, page, off, cur_len);
		if (ret)
			goto out_lane;

		if (bip) {
			ret = btt_rw_integrity(btt, bip, arena, new_postmap,
						WRITE);
			if (ret)
				goto out_lane;
		}

		lock_map(arena, premap);
		ret = btt_map_read(arena, premap, &old_postmap, NULL, &e_flag,
				NVDIMM_IO_ATOMIC);
		if (ret)
			goto out_map;
		if (old_postmap >= arena->internal_nlba) {
			ret = -EIO;
			goto out_map;
		}
		if (e_flag)
			set_e_flag(old_postmap);

		log.lba = cpu_to_le32(premap);
		log.old_map = cpu_to_le32(old_postmap);
		log.new_map = cpu_to_le32(new_postmap);
		log.seq = cpu_to_le32(arena->freelist[lane].seq);
		sub = arena->freelist[lane].sub;
		ret = btt_flog_write(arena, lane, sub, &log);
		if (ret)
			goto out_map;

		ret = btt_map_write(arena, premap, new_postmap, 0, 0,
			NVDIMM_IO_ATOMIC);
		if (ret)
			goto out_map;

		unlock_map(arena, premap);
		nd_region_release_lane(btt->nd_region, lane);

		if (e_flag) {
			ret = arena_clear_freelist_error(arena, lane);
			if (ret)
				return ret;
		}

		len -= cur_len;
		off += cur_len;
		sector += btt->sector_size >> SECTOR_SHIFT;
	}

	return 0;

 out_map:
	unlock_map(arena, premap);
 out_lane:
	nd_region_release_lane(btt->nd_region, lane);
	return ret;
}