+static int nvme_cmb_qdepth(struct nvme_dev *dev, int nr_io_queues,
+ int entry_size)
+{
+ int q_depth = dev->q_depth;
+ unsigned q_size_aligned = roundup(q_depth * entry_size, dev->page_size);
+
+ if (q_size_aligned * nr_io_queues > dev->cmb_size) {
+ u64 mem_per_q = div_u64(dev->cmb_size, nr_io_queues);
+ mem_per_q = round_down(mem_per_q, dev->page_size);
+ q_depth = div_u64(mem_per_q, entry_size);
+
+ /*
+ * Ensure the reduced q_depth is above some threshold where it
+ * would be better to map queues in system memory with the
+ * original depth
+ */
+ if (q_depth < 64)
+ return -ENOMEM;
+ }
+
+ return q_depth;
+}
+
+static int nvme_alloc_sq_cmds(struct nvme_dev *dev, struct nvme_queue *nvmeq,
+ int qid, int depth)
+{
+ if (qid && dev->cmb && use_cmb_sqes && NVME_CMB_SQS(dev->cmbsz)) {
+ unsigned offset = (qid - 1) *
+ roundup(SQ_SIZE(depth), dev->page_size);
+ nvmeq->sq_dma_addr = dev->cmb_dma_addr + offset;
+ nvmeq->sq_cmds_io = dev->cmb + offset;
+ } else {
+ nvmeq->sq_cmds = dma_alloc_coherent(dev->dev, SQ_SIZE(depth),
+ &nvmeq->sq_dma_addr, GFP_KERNEL);
+ if (!nvmeq->sq_cmds)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+