[PATCH v4 01/15] nvmet: Rapid Path Failure Recovery set controller identify fields

[Mohamed Khalfella <mkhalfella@purestorage.com>]

TP8028 Rapid Path Failure Recovery defined new fields in controller
identify response. The newly defined fields are:

- CIU (Controller Instance UNIQUIFIER): is an 8bit non-zero value that
is assigned a random value when controller is first created. The value
is expected to be incremented when RDY bit in CSTS register is asserted
- CIRN (Controller Instance Random Number): is 64bit random value that
gets generated when controller is created. CIRN is regenerated everytime
RDY bit is CSTS register is asserted.
- CCRL (Cross-Controller Reset Limit) is an 8bit value that defines the
maximum number of in-progress controller reset operations. CCRL is
hardcoded to 4 as recommended by TP8028.

Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
---
 drivers/nvme/target/admin-cmd.c |  5 +++++
 drivers/nvme/target/core.c      |  9 +++++++++
 drivers/nvme/target/nvmet.h     |  2 ++
 include/linux/nvme.h            | 10 ++++++++--
 4 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index ca5b08ce1211..ec09e30eca18 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -695,6 +695,11 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 
 	id->cntlid = cpu_to_le16(ctrl->cntlid);
 	id->ver = cpu_to_le32(ctrl->subsys->ver);
+	if (!nvmet_is_disc_subsys(ctrl->subsys)) {
+		id->ciu = ctrl->ciu;
+		id->cirn = cpu_to_le64(ctrl->cirn);
+		id->ccrl = NVMF_CCR_LIMIT;
+	}
 
 	/* XXX: figure out what to do about RTD3R/RTD3 */
 	id->oaes = cpu_to_le32(NVMET_AEN_CFG_OPTIONAL);
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 9238e13bd480..e8b945a01f35 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1396,6 +1396,10 @@ static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
 		return;
 	}
 
+	if (!nvmet_is_disc_subsys(ctrl->subsys)) {
+		ctrl->ciu = ((u8)(ctrl->ciu + 1)) ? : 1;
+		ctrl->cirn = get_random_u64();
+	}
 	ctrl->csts = NVME_CSTS_RDY;
 
 	/*
@@ -1661,6 +1665,11 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args)
 	}
 	ctrl->cntlid = ret;
 
+	if (!nvmet_is_disc_subsys(ctrl->subsys)) {
+		ctrl->ciu = get_random_u8() ? : 1;
+		ctrl->cirn = get_random_u64();
+	}
+
 	/*
 	 * Discovery controllers may use some arbitrary high value
 	 * in order to cleanup stale discovery sessions
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 319d6a5e9cf0..2181ac45ae7f 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -264,7 +264,9 @@ struct nvmet_ctrl {
 
 	uuid_t			hostid;
 	u16			cntlid;
+	u8			ciu;
 	u32			kato;
+	u64			cirn;
 
 	struct nvmet_port	*port;
 
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 655d194f8e72..7746b6d30349 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -21,6 +21,8 @@
 #define NVMF_TRADDR_SIZE	256
 #define NVMF_TSAS_SIZE		256
 
+#define NVMF_CCR_LIMIT		4
+
 #define NVME_DISC_SUBSYS_NAME	"nqn.2014-08.org.nvmexpress.discovery"
 
 #define NVME_NSID_ALL		0xffffffff
@@ -328,7 +330,10 @@ struct nvme_id_ctrl {
 	__le16			crdt1;
 	__le16			crdt2;
 	__le16			crdt3;
-	__u8			rsvd134[122];
+	__u8			rsvd134[1];
+	__u8			ciu;
+	__le64			cirn;
+	__u8			rsvd144[112];
 	__le16			oacs;
 	__u8			acl;
 	__u8			aerl;
@@ -389,7 +394,8 @@ struct nvme_id_ctrl {
 	__u8			msdbd;
 	__u8			rsvd1804[2];
 	__u8			dctype;
-	__u8			rsvd1807[241];
+	__u8			ccrl;
+	__u8			rsvd1808[240];
 	struct nvme_id_power_state	psd[32];
 	__u8			vs[1024];
 };
-- 
2.52.0