Re: [PATCH] nvme: add support for TP4084 - Time-to-Ready Enhancements

[Christoph Hellwig <hch@lst.de>]

On Wed, May 18, 2022 at 08:36:47AM -0600, Keith Busch wrote:
> On Wed, May 18, 2022 at 08:40:40AM +0200, Christoph Hellwig wrote:
> > +static int nvme_identify_ns_cs_indep(struct nvme_ctrl *ctrl, unsigned nsid,
> > +			struct nvme_id_ns_cs_indep **id)
> > +{
> > +	struct nvme_command c = {
> > +		.identify.opcode	= nvme_admin_identify,
> > +		.identify.nsid		= cpu_to_le32(nsid),
> > +		.identify.cns		= NVME_ID_CNS_NS_CS_INDEP,
> > +	};
> > +	int error;
> 
> Every other place in this driver calls this value 'ret'.

Except for nvme_identify_ns, where I copied it from :)

But I can change it to ret.

> 
> > -static int nvme_wait_ready(struct nvme_ctrl *ctrl, u64 cap, bool enabled)
> > +static int nvme_wait_ready(struct nvme_ctrl *ctrl, bool enabled)
> >  {
> > -	unsigned long timeout =
> > -		((NVME_CAP_TIMEOUT(cap) + 1) * HZ / 2) + jiffies;
> > +	unsigned long timeout = ((ctrl->enable_timeout + 1) * HZ / 2) + jiffies;
> 
> I think we need to continue using the NVME_CAP_TIMEOUT() value when 'enabled'
> is false. The enable_timeout is only applicable for the 0->1 transition and may
> be too short if CRIME is set or too long when it's not.

Yeah.  So we could do something like this instead, which even avoids
the new member in struct nvme_ctrl:

---
From 032b8a803bf5bec4c4f206d9cc5a4b1160e0dc69 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 16 May 2022 15:09:21 +0200
Subject: nvme: add support for TP4084 - Time-to-Ready Enhancements

Add support for using longer timeouts during controller initialization
and letting the controller come up with namespaces that are not ready
for I/O yet.  We skip these not ready namespaces during scanning and
only bring them online once anoter scan is kicked off by the AEN that
is set when the NRDY bit gets set in the  I/O Command Set Independent
Identify Namespace Data Structure.   This asynchronous probing avoids
blocking the kernel boot when controllers take a very long time to
recover after unclean shutdowns (up to minutes).

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvme/host/constants.c |  1 +
 drivers/nvme/host/core.c      | 76 ++++++++++++++++++++++++++++++++---
 include/linux/nvme.h          | 31 ++++++++++++++
 3 files changed, 102 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/host/constants.c b/drivers/nvme/host/constants.c
index 1dd1d78de2956..4910543f00ff9 100644
--- a/drivers/nvme/host/constants.c
+++ b/drivers/nvme/host/constants.c
@@ -91,6 +91,7 @@ static const char * const nvme_statuses[] = {
 	[NVME_SC_NS_WRITE_PROTECTED] = "Namespace is Write Protected",
 	[NVME_SC_CMD_INTERRUPTED] = "Command Interrupted",
 	[NVME_SC_TRANSIENT_TR_ERR] = "Transient Transport Error",
+	[NVME_SC_ADMIN_COMMAND_MEDIA_NOT_READY] = "Admin Command Media Not Ready",
 	[NVME_SC_INVALID_IO_CMD_SET] = "Invalid IO Command Set",
 	[NVME_SC_LBA_RANGE] = "LBA Out of Range",
 	[NVME_SC_CAP_EXCEEDED] = "Capacity Exceeded",
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 42f9772abc4d0..faeb032719134 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1427,6 +1427,32 @@ static int nvme_identify_ns(struct nvme_ctrl *ctrl, unsigned nsid,
 	return error;
 }
 
+static int nvme_identify_ns_cs_indep(struct nvme_ctrl *ctrl, unsigned nsid,
+			struct nvme_id_ns_cs_indep **id)
+{
+	struct nvme_command c = {
+		.identify.opcode	= nvme_admin_identify,
+		.identify.nsid		= cpu_to_le32(nsid),
+		.identify.cns		= NVME_ID_CNS_NS_CS_INDEP,
+	};
+	int ret;
+
+	*id = kmalloc(sizeof(**id), GFP_KERNEL);
+	if (!*id)
+		return -ENOMEM;
+
+	ret = nvme_submit_sync_cmd(ctrl->admin_q, &c, *id, sizeof(**id));
+	if (ret) {
+		dev_warn(ctrl->device,
+			 "Identify namespace (CS independent) failed (%d)\n",
+			 ret);
+		kfree(*id);
+		return ret;
+	}
+
+	return 0;
+}
+
 static int nvme_features(struct nvme_ctrl *dev, u8 op, unsigned int fid,
 		unsigned int dword11, void *buffer, size_t buflen, u32 *result)
 {
@@ -2103,10 +2129,9 @@ static const struct block_device_operations nvme_bdev_ops = {
 	.pr_ops		= &nvme_pr_ops,
 };
 
-static int nvme_wait_ready(struct nvme_ctrl *ctrl, u64 cap, bool enabled)
+static int nvme_wait_ready(struct nvme_ctrl *ctrl, u32 timeout, bool enabled)
 {
-	unsigned long timeout =
-		((NVME_CAP_TIMEOUT(cap) + 1) * HZ / 2) + jiffies;
+	unsigned long timeout_jiffies = ((timeout + 1) * HZ / 2) + jiffies;
 	u32 csts, bit = enabled ? NVME_CSTS_RDY : 0;
 	int ret;
 
@@ -2119,7 +2144,7 @@ static int nvme_wait_ready(struct nvme_ctrl *ctrl, u64 cap, bool enabled)
 		usleep_range(1000, 2000);
 		if (fatal_signal_pending(current))
 			return -EINTR;
-		if (time_after(jiffies, timeout)) {
+		if (time_after(jiffies, timeout_jiffies)) {
 			dev_err(ctrl->device,
 				"Device not ready; aborting %s, CSTS=0x%x\n",
 				enabled ? "initialisation" : "reset", csts);
@@ -2150,13 +2175,14 @@ int nvme_disable_ctrl(struct nvme_ctrl *ctrl)
 	if (ctrl->quirks & NVME_QUIRK_DELAY_BEFORE_CHK_RDY)
 		msleep(NVME_QUIRK_DELAY_AMOUNT);
 
-	return nvme_wait_ready(ctrl, ctrl->cap, false);
+	return nvme_wait_ready(ctrl, NVME_CAP_TIMEOUT(ctrl->cap), false);
 }
 EXPORT_SYMBOL_GPL(nvme_disable_ctrl);
 
 int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
 {
 	unsigned dev_page_min;
+	u32 timeout;
 	int ret;
 
 	ret = ctrl->ops->reg_read64(ctrl, NVME_REG_CAP, &ctrl->cap);
@@ -2177,6 +2203,27 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
 		ctrl->ctrl_config = NVME_CC_CSS_CSI;
 	else
 		ctrl->ctrl_config = NVME_CC_CSS_NVM;
+
+	if (ctrl->cap & NVME_CAP_CRMS_CRWMS) {
+		u32 crto;
+
+		ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CRTO, &crto);
+		if (ret) {
+			dev_err(ctrl->device, "Reading CRTO failed (%d)\n",
+				ret);
+			return ret;
+		}
+
+		if (ctrl->cap & NVME_CAP_CRMS_CRIMS) {
+			ctrl->ctrl_config |= NVME_CC_CRIME;
+			timeout = NVME_CRTO_CRIMT(crto);
+		} else {
+			timeout = NVME_CRTO_CRWMT(crto);
+		}
+	} else {
+		timeout = NVME_CAP_TIMEOUT(ctrl->cap);
+	}
+
 	ctrl->ctrl_config |= (NVME_CTRL_PAGE_SHIFT - 12) << NVME_CC_MPS_SHIFT;
 	ctrl->ctrl_config |= NVME_CC_AMS_RR | NVME_CC_SHN_NONE;
 	ctrl->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;
@@ -2185,7 +2232,7 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
 	ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
 	if (ret)
 		return ret;
-	return nvme_wait_ready(ctrl, ctrl->cap, true);
+	return nvme_wait_ready(ctrl, timeout, true);
 }
 EXPORT_SYMBOL_GPL(nvme_enable_ctrl);
 
@@ -4092,11 +4139,26 @@ static void nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_ids *ids)
 static void nvme_validate_or_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
 	struct nvme_ns_ids ids = { };
+	struct nvme_id_ns_cs_indep *id;
 	struct nvme_ns *ns;
+	bool ready = true;
 
 	if (nvme_identify_ns_descs(ctrl, nsid, &ids))
 		return;
 
+	/*
+	 * Check if the namespace is ready.  If not ignore it, we will get an
+	 * AEN once it becomes ready and restart the scan.
+	 */
+	if ((ctrl->cap & NVME_CAP_CRMS_CRIMS) &&
+	    !nvme_identify_ns_cs_indep(ctrl, nsid, &id)) {
+		ready = id->nstat & NVME_NSTAT_NRDY;
+		kfree(id);
+	}
+
+	if (!ready)
+		return;
+
 	ns = nvme_find_get_ns(ctrl, nsid);
 	if (ns) {
 		nvme_validate_ns(ns, &ids);
@@ -4841,6 +4903,8 @@ static inline void _nvme_check_size(void)
 	BUILD_BUG_ON(sizeof(struct nvme_command) != 64);
 	BUILD_BUG_ON(sizeof(struct nvme_id_ctrl) != NVME_IDENTIFY_DATA_SIZE);
 	BUILD_BUG_ON(sizeof(struct nvme_id_ns) != NVME_IDENTIFY_DATA_SIZE);
+	BUILD_BUG_ON(sizeof(struct nvme_id_ns_cs_indep) !=
+			NVME_IDENTIFY_DATA_SIZE);
 	BUILD_BUG_ON(sizeof(struct nvme_id_ns_zns) != NVME_IDENTIFY_DATA_SIZE);
 	BUILD_BUG_ON(sizeof(struct nvme_id_ns_nvm) != NVME_IDENTIFY_DATA_SIZE);
 	BUILD_BUG_ON(sizeof(struct nvme_id_ctrl_zns) != NVME_IDENTIFY_DATA_SIZE);
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 5f6d432fa06a6..29ec3e3481ff6 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -137,6 +137,7 @@ enum {
 	NVME_REG_CMBMSC = 0x0050,	/* Controller Memory Buffer Memory
 					 * Space Control
 					 */
+	NVME_REG_CRTO	= 0x0068,	/* Controller Ready Timeouts */
 	NVME_REG_PMRCAP	= 0x0e00,	/* Persistent Memory Capabilities */
 	NVME_REG_PMRCTL	= 0x0e04,	/* Persistent Memory Region Control */
 	NVME_REG_PMRSTS	= 0x0e08,	/* Persistent Memory Region Status */
@@ -161,6 +162,9 @@ enum {
 #define NVME_CMB_BIR(cmbloc)	((cmbloc) & 0x7)
 #define NVME_CMB_OFST(cmbloc)	(((cmbloc) >> 12) & 0xfffff)
 
+#define NVME_CRTO_CRIMT(crto)	((crto) >> 16)
+#define NVME_CRTO_CRWMT(crto)	((crto) & 0xffff)
+
 enum {
 	NVME_CMBSZ_SQS		= 1 << 0,
 	NVME_CMBSZ_CQS		= 1 << 1,
@@ -204,6 +208,7 @@ enum {
 	NVME_CC_SHN_MASK	= 3 << NVME_CC_SHN_SHIFT,
 	NVME_CC_IOSQES		= NVME_NVM_IOSQES << NVME_CC_IOSQES_SHIFT,
 	NVME_CC_IOCQES		= NVME_NVM_IOCQES << NVME_CC_IOCQES_SHIFT,
+	NVME_CC_CRIME		= 1 << 24,
 };
 
 enum {
@@ -227,6 +232,11 @@ enum {
 	NVME_CAP_CSS_CSI	= 1 << 6,
 };
 
+enum {
+	NVME_CAP_CRMS_CRIMS	= 1ULL << 59,
+	NVME_CAP_CRMS_CRWMS	= 1ULL << 60,
+};
+
 struct nvme_id_power_state {
 	__le16			max_power;	/* centiwatts */
 	__u8			rsvd2;
@@ -414,6 +424,21 @@ struct nvme_id_ns {
 	__u8			vs[3712];
 };
 
+/* I/O Command Set Independent Identify Namespace Data Structure */
+struct nvme_id_ns_cs_indep {
+	__u8			nsfeat;
+	__u8			nmic;
+	__u8			rescap;
+	__u8			fpi;
+	__le32			anagrpid;
+	__u8			nsattr;
+	__u8			rsvd9;
+	__le16			nvmsetid;
+	__le16			endgid;
+	__u8			nstat;
+	__u8			rsvd15[4081];
+};
+
 struct nvme_zns_lbafe {
 	__le64			zsze;
 	__u8			zdes;
@@ -478,6 +503,7 @@ enum {
 	NVME_ID_CNS_NS_DESC_LIST	= 0x03,
 	NVME_ID_CNS_CS_NS		= 0x05,
 	NVME_ID_CNS_CS_CTRL		= 0x06,
+	NVME_ID_CNS_NS_CS_INDEP		= 0x08,
 	NVME_ID_CNS_NS_PRESENT_LIST	= 0x10,
 	NVME_ID_CNS_NS_PRESENT		= 0x11,
 	NVME_ID_CNS_CTRL_NS_LIST	= 0x12,
@@ -531,6 +557,10 @@ enum {
 	NVME_NS_DPS_PI_TYPE3	= 3,
 };
 
+enum {
+	NVME_NSTAT_NRDY		= 1 << 0,
+};
+
 enum {
 	NVME_NVM_NS_16B_GUARD	= 0,
 	NVME_NVM_NS_32B_GUARD	= 1,
@@ -1592,6 +1622,7 @@ enum {
 	NVME_SC_NS_WRITE_PROTECTED	= 0x20,
 	NVME_SC_CMD_INTERRUPTED		= 0x21,
 	NVME_SC_TRANSIENT_TR_ERR	= 0x22,
+	NVME_SC_ADMIN_COMMAND_MEDIA_NOT_READY = 0x24,
 	NVME_SC_INVALID_IO_CMD_SET	= 0x2C,
 
 	NVME_SC_LBA_RANGE		= 0x80,
-- 
2.30.2