From: "Martin K. Petersen" <martin.petersen@oracle.com>
Date: Fri, 25 Aug 2017 19:14:50 -0400
Subject: nvme: honor RTD3 Entry Latency for shutdowns
Patch-mainline: v4.14-rc1
Git-commit: 07fbd32a6b215d8b2fc01ccc89622207b9b782fd
References: FATE#323952, FATE#322506

If an NVMe controller reports RTD3 Entry Latency larger than
shutdown_timeout, up to a maximum of 60 seconds, use that value to set
the shutdown timer. Otherwise fall back to the module parameter which
defaults to 5 seconds.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
[hch: removed do_div, made transition time local scope]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/nvme/host/core.c |   16 +++++++++++++++-
 drivers/nvme/host/nvme.h |    1 +
 2 files changed, 16 insertions(+), 1 deletion(-)

--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1465,7 +1465,7 @@ EXPORT_SYMBOL_GPL(nvme_enable_ctrl);
 
 int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl)
 {
-	unsigned long timeout = jiffies + (shutdown_timeout * HZ);
+	unsigned long timeout = jiffies + (ctrl->shutdown_timeout * HZ);
 	u32 csts;
 	int ret;
 
@@ -1833,6 +1833,20 @@ int nvme_init_identify(struct nvme_ctrl
 	ctrl->sgls = le32_to_cpu(id->sgls);
 	ctrl->kas = le16_to_cpu(id->kas);
 
+	if (id->rtd3e) {
+		/* us -> s */
+		u32 transition_time = le32_to_cpu(id->rtd3e) / 1000000;
+
+		ctrl->shutdown_timeout = clamp_t(unsigned int, transition_time,
+						 shutdown_timeout, 60);
+
+		if (ctrl->shutdown_timeout != shutdown_timeout)
+			dev_warn(ctrl->device,
+				 "Shutdown timeout set to %u seconds\n",
+				 ctrl->shutdown_timeout);
+	} else
+		ctrl->shutdown_timeout = shutdown_timeout;
+
 	ctrl->npss = id->npss;
 	ctrl->apsta = id->apsta;
 	prev_apst_enabled = ctrl->apst_enabled;
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -162,6 +162,7 @@ struct nvme_ctrl {
 	u16 kas;
 	u8 npss;
 	u8 apsta;
+	unsigned int shutdown_timeout;
 	unsigned int kato;
 	bool subsystem;
 	unsigned long quirks;