Commit 29f69753 authored by Keith Busch's avatar Keith Busch
Browse files

nvme: implement support for relaxed effects 



NVM Express TP4167 provides a way for controllers to report a relaxed
execution constraint. Specifically, it notifies of exclusivity for IO
vs. admin commands instead of grouping these together. If set, then we
don't need to freeze IO in order to execute that admin command. The
freezing distrupts IO processes, so it's nice to avoid that if the
controller tells us it's not necessary.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
parent 79bd7eab

drivers/nvme/host/core.c

+4 −0
Original line number Diff line number Diff line
@@ -1153,6 +1153,10 @@ u32 nvme_command_effects(struct nvme_ctrl *ctrl, struct nvme_ns *ns, u8 opcode) 
		effects &= ~NVME_CMD_EFFECTS_CSE_MASK;

	} else {

		effects = le32_to_cpu(ctrl->effects->acs[opcode]);



		/* Ignore execution restrictions if any relaxation bits are set */

		if (effects & NVME_CMD_EFFECTS_CSER_MASK)

			effects &= ~NVME_CMD_EFFECTS_CSE_MASK;

	}



	return effects;

include/linux/nvme.h

+1 −0
Original line number Diff line number Diff line
@@ -646,6 +646,7 @@ enum { 
	NVME_CMD_EFFECTS_NCC		= 1 << 2,

	NVME_CMD_EFFECTS_NIC		= 1 << 3,

	NVME_CMD_EFFECTS_CCC		= 1 << 4,

	NVME_CMD_EFFECTS_CSER_MASK	= GENMASK(15, 14),

	NVME_CMD_EFFECTS_CSE_MASK	= GENMASK(18, 16),

	NVME_CMD_EFFECTS_UUID_SEL	= 1 << 19,

	NVME_CMD_EFFECTS_SCOPE_MASK	= GENMASK(31, 20),