From 29f6975332479f92233594901c649ff4d71f8cb6 Mon Sep 17 00:00:00 2001
From: Keith Busch <kbusch@kernel.org>
Date: Mon, 5 Feb 2024 11:10:25 -0800
Subject: [PATCH] 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
drivers/nvme/host/core.c | 4 ++++
include/linux/nvme.h | 1 +
2 files changed, 5 insertions(+)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 60537c9224bf9..0a96362912ced 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -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;
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index bc605ec4a3fd0..3ef4053ea9500 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -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),
--
2.30.2