Commit 02cb00e2 authored by Max Gurtovoy's avatar Max Gurtovoy Committed by Keith Busch
Browse files

nvmet: Add get_mdts op for controllers 



Some transports, such as RDMA, would like to set the Maximum Data
Transfer Size (MDTS) according to device/port/ctrl characteristics.
This will enable the transport to set the optimal MDTS according to
controller needs and device capabilities. Add a new nvmet transport
op that is called during ctrl identification. This will not effect
transports that don't implement this option. The return value of the new
op is according to the NVMe spec definition for MDTS.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: default avatarIsrael Rukshin <israelr@mellanox.com>
parent 2db24e4a

drivers/nvme/target/admin-cmd.c

+6 −2
Original line number Diff line number Diff line
@@ -369,8 +369,12 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req) 
	/* we support multiple ports, multiples hosts and ANA: */

	id->cmic = (1 << 0) | (1 << 1) | (1 << 3);



	/* no limit on data transfer sizes for now */

	/* Limit MDTS according to transport capability */

	if (ctrl->ops->get_mdts)

		id->mdts = ctrl->ops->get_mdts(ctrl);

	else

		id->mdts = 0;



	id->cntlid = cpu_to_le16(ctrl->cntlid);

	id->ver = cpu_to_le32(ctrl->subsys->ver);

drivers/nvme/target/nvmet.h

+1 −0
Original line number Diff line number Diff line
@@ -289,6 +289,7 @@ struct nvmet_fabrics_ops { 
			struct nvmet_port *port, char *traddr);

	u16 (*install_queue)(struct nvmet_sq *nvme_sq);

	void (*discovery_chg)(struct nvmet_port *port);

	u8 (*get_mdts)(const struct nvmet_ctrl *ctrl);

};



#define NVMET_MAX_INLINE_BIOVEC	8