[PATCH RFC 2/5] nvme: Add CDQ data structures to host driver

[Joel Granados]

Add host-side Controller Data Queue (CDQ) data structures and function
declarations to drivers/nvme/host/nvme.h:
- Add cdqs xarray to nvme_ctrl for managing CDQ instances
- Add cdq_nvme_queue structure containing:
  - DMA mapping state
  - PRP list management
  - eventfd context for tail pointer event notifications

Signed-off-by: Joel Granados <joel.granados at kernel.org>
---
 drivers/nvme/host/nvme.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 9971045dbc05e9bb9d7fa32ad540fd107d8c8b83..30d5052c7728c0d5c5e8772ff531bc672e96940f 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -466,6 +466,7 @@ struct nvme_ctrl {
 	enum nvme_dctype dctype;
 
 	u16			awupf; /* 0's based value. */
+	struct xarray cdqs; /* Controller Data Queue */
 };
 
 static inline enum nvme_ctrl_state nvme_ctrl_state(struct nvme_ctrl *ctrl)
@@ -619,6 +620,20 @@ static inline unsigned long nvme_get_virt_boundary(struct nvme_ctrl *ctrl,
 	return NVME_CTRL_PAGE_SIZE - 1;
 }
 
+#define MAX_NR_CDQ_PRPS		20
+struct cdq_nvme_queue {
+	struct nvme_ctrl *ctrl;
+	__u32	size_nbyte;
+	u16 cdq_id;
+	struct eventfd_ctx *tpt_efd_ctx;
+	struct sg_table sgt;
+	struct page **pages;
+	unsigned long nr_pages;
+	void *prp_lists[MAX_NR_CDQ_PRPS];
+	dma_addr_t prp_lists_dma[MAX_NR_CDQ_PRPS];
+	u32 nr_prp_lists; /*number of PRP lists*/
+};
+
 struct nvme_ctrl_ops {
 	const char *name;
 	struct module *module;

-- 
2.50.1