From 97be8b969d2930b8c56da49e1d871d0a0cb4a6bc Mon Sep 17 00:00:00 2001
From: Alexander Motin <mav@FreeBSD.org>
Date: Wed, 14 Aug 2019 16:12:03 +0000
Subject: [PATCH] Report NOIOB and NPWG fields as stripe size.

Namespace Optimal I/O Boundary field added in NVMe 1.3 and Namespace
Preferred Write Granularity added in 1.4 allow upper layers to align
I/Os for improved SSD performance and endurance.

I don't have hardware reportig those yet, but NPWG could probably be
reported by bhyve.

MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.
---
 sys/dev/nvme/nvme_ns.c      | 52 +++++++++++++++++++++----------------
 sys/dev/nvme/nvme_private.h |  2 +-
 2 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/sys/dev/nvme/nvme_ns.c b/sys/dev/nvme/nvme_ns.c
index df38810dc663..8eff0b4802cd 100644
--- a/sys/dev/nvme/nvme_ns.c
+++ b/sys/dev/nvme/nvme_ns.c
@@ -231,7 +231,11 @@ uint32_t
 nvme_ns_get_stripesize(struct nvme_namespace *ns)
 {
 
-	return (ns->stripesize);
+	if (((ns->data.nsfeat >> NVME_NS_DATA_NSFEAT_NPVALID_SHIFT) &
+	    NVME_NS_DATA_NSFEAT_NPVALID_MASK) != 0 && ns->data.npwg != 0) {
+		return ((ns->data.npwg + 1) * nvme_ns_get_sector_size(ns));
+	}
+	return (ns->boundary);
 }
 
 static void
@@ -447,12 +451,12 @@ nvme_ns_bio_process(struct nvme_namespace *ns, struct bio *bp,
 
 	bp->bio_driver1 = cb_fn;
 
-	if (ns->stripesize > 0 &&
+	if (ns->boundary > 0 &&
 	    (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
 		num_bios = nvme_get_num_segments(bp->bio_offset,
-		    bp->bio_bcount, ns->stripesize);
+		    bp->bio_bcount, ns->boundary);
 		if (num_bios > 1)
-			return (nvme_ns_split_bio(ns, bp, ns->stripesize));
+			return (nvme_ns_split_bio(ns, bp, ns->boundary));
 	}
 
 	switch (bp->bio_cmd) {
@@ -511,25 +515,6 @@ nvme_ns_construct(struct nvme_namespace *ns, uint32_t id,
 
 	ns->ctrlr = ctrlr;
 	ns->id = id;
-	ns->stripesize = 0;
-
-	/*
-	 * Older Intel devices advertise in vendor specific space an alignment
-	 * that improves performance.  If present use for the stripe size.  NVMe
-	 * 1.3 standardized this as NOIOB, and newer Intel drives use that.
-	 */
-	switch (pci_get_devid(ctrlr->dev)) {
-	case 0x09538086:		/* Intel DC PC3500 */
-	case 0x0a538086:		/* Intel DC PC3520 */
-	case 0x0a548086:		/* Intel DC PC4500 */
-	case 0x0a558086:		/* Dell Intel P4600 */
-		if (ctrlr->cdata.vs[3] != 0)
-			ns->stripesize =
-			    (1 << ctrlr->cdata.vs[3]) * ctrlr->min_page_size;
-		break;
-	default:
-		break;
-	}
 
 	/*
 	 * Namespaces are reconstructed after a controller reset, so check
@@ -576,6 +561,27 @@ nvme_ns_construct(struct nvme_namespace *ns, uint32_t id,
 		return (ENXIO);
 	}
 
+	/*
+	 * Older Intel devices advertise in vendor specific space an alignment
+	 * that improves performance.  If present use for the stripe size.  NVMe
+	 * 1.3 standardized this as NOIOB, and newer Intel drives use that.
+	 */
+	switch (pci_get_devid(ctrlr->dev)) {
+	case 0x09538086:		/* Intel DC PC3500 */
+	case 0x0a538086:		/* Intel DC PC3520 */
+	case 0x0a548086:		/* Intel DC PC4500 */
+	case 0x0a558086:		/* Dell Intel P4600 */
+		if (ctrlr->cdata.vs[3] != 0)
+			ns->boundary =
+			    (1 << ctrlr->cdata.vs[3]) * ctrlr->min_page_size;
+		else
+			ns->boundary = 0;
+		break;
+	default:
+		ns->boundary = ns->data.noiob * nvme_ns_get_sector_size(ns);
+		break;
+	}
+
 	if (nvme_ctrlr_has_dataset_mgmt(&ctrlr->cdata))
 		ns->flags |= NVME_NS_DEALLOCATE_SUPPORTED;
 
diff --git a/sys/dev/nvme/nvme_private.h b/sys/dev/nvme/nvme_private.h
index 854750cf9fbf..dda13bcce280 100644
--- a/sys/dev/nvme/nvme_private.h
+++ b/sys/dev/nvme/nvme_private.h
@@ -223,7 +223,7 @@ struct nvme_namespace {
 	uint32_t			flags;
 	struct cdev			*cdev;
 	void				*cons_cookie[NVME_MAX_CONSUMERS];
-	uint32_t			stripesize;
+	uint32_t			boundary;
 	struct mtx			lock;
 };