[PATCHv3 11/11] nvme: add rotational support

[Keith Busch]

From: Matias Bjørling <matias.bjorling at wdc.com>

Rotational devices, such as hard-drives, can be detected using
the rotational bit in the namespace independent identify namespace
data structure. Make the bit visible to the block layer through the
rotational queue setting.

Note that rotational devices typically can be used to generate random
entropy, the device is therefore also added as a block device that adds
entropy.

Signed-off-by: Matias Bjørling <matias.bjorling at wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen at oracle.com>
Signed-off-by: Keith Busch <kbusch at kernel.org>
---
 drivers/nvme/host/core.c | 5 +++++
 include/linux/nvme.h     | 1 +
 2 files changed, 6 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 4361fc7e8a225..a47149858be59 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -42,6 +42,7 @@ struct nvme_ns_info {
 	bool is_readonly;
 	bool is_ready;
 	bool is_removed;
+	bool is_rotational;
 };
 
 unsigned int admin_timeout = 60;
@@ -1615,6 +1616,7 @@ static int nvme_ns_info_from_id_cs_indep(struct nvme_ctrl *ctrl,
 		info->is_shared = id->nmic & NVME_NS_NMIC_SHARED;
 		info->is_readonly = id->nsattr & NVME_NS_ATTR_RO;
 		info->is_ready = id->nstat & NVME_NSTAT_NRDY;
+		info->is_rotational = id->nsfeat & NVME_NS_ROTATIONAL;
 	}
 	kfree(id);
 	return ret;
@@ -2162,6 +2164,9 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
 	else
 		lim.features &= ~(BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA);
 
+	if (info->is_rotational)
+		lim.features |= BLK_FEAT_ROTATIONAL | BLK_FEAT_ADD_RANDOM;
+
 	/*
 	 * Register a metadata profile for PI, or the plain non-integrity NVMe
 	 * metadata masquerading as Type 0 if supported, otherwise reject block
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 9bd37ec01c072..5976285192ae4 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -563,6 +563,7 @@ enum {
 	NVME_NS_FLBAS_LBA_SHIFT	= 1,
 	NVME_NS_FLBAS_META_EXT	= 0x10,
 	NVME_NS_NMIC_SHARED	= 1 << 0,
+	NVME_NS_ROTATIONAL	= 1 << 4,
 	NVME_LBAF_RP_BEST	= 0,
 	NVME_LBAF_RP_BETTER	= 1,
 	NVME_LBAF_RP_GOOD	= 2,
-- 
2.43.5