[PATCH 13/15] nvmet: Add metadata/T10-PI support

[Max Gurtovoy <maxg@mellanox.com>]

From: Israel Rukshin <israelr@mellanox.com>

Expose the namespace metadata format when PI is enabled. The user needs
to enable the capability per subsystem and the other metadata properties
are taken from the namespace/bdev.

Usage example:
echo 1 > /config/nvmet/subsystems/${NAME}/attr_pi_enable

Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
---
 drivers/nvme/target/admin-cmd.c   | 23 +++++++++++++++++++----
 drivers/nvme/target/configfs.c    | 24 ++++++++++++++++++++++++
 drivers/nvme/target/fabrics-cmd.c | 11 +++++++++++
 drivers/nvme/target/nvmet.h       |  5 +++++
 4 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 19ae155..20e7f08 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -346,8 +346,8 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 	/* we support multiple ports, multiples hosts and ANA: */
 	id->cmic = (1 << 0) | (1 << 1) | (1 << 3);
 
-	/* no limit on data transfer sizes for now */
-	id->mdts = 0;
+	/* Limit MDTS for metadata capable controllers (assume mpsmin is 4k) */
+	id->mdts = ctrl->pi_support ? ilog2(NVMET_T10_PI_MAX_KB_SZ >> 2) : 0;
 	id->cntlid = cpu_to_le16(ctrl->cntlid);
 	id->ver = cpu_to_le32(ctrl->subsys->ver);
 
@@ -405,9 +405,13 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 
 	strlcpy(id->subnqn, ctrl->subsys->subsysnqn, sizeof(id->subnqn));
 
-	/* Max command capsule size is sqe + single page of in-capsule data */
+	/*
+	 * Max command capsule size is sqe + single page of in-capsule data.
+	 * Disable inline data for Metadata capable controllers.
+	 */
 	id->ioccsz = cpu_to_le32((sizeof(struct nvme_command) +
-				  req->port->inline_data_size) / 16);
+				  req->port->inline_data_size *
+				  !ctrl->pi_support) / 16);
 	/* Max response capsule size is cqe */
 	id->iorcsz = cpu_to_le32(sizeof(struct nvme_completion) / 16);
 
@@ -437,6 +441,7 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 
 static void nvmet_execute_identify_ns(struct nvmet_req *req)
 {
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	struct nvmet_ns *ns;
 	struct nvme_id_ns *id;
 	u16 status = 0;
@@ -493,6 +498,16 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 
 	id->lbaf[0].ds = ns->blksize_shift;
 
+	if (ctrl->pi_support && nvmet_ns_has_pi(ns)) {
+		id->dpc = NVME_NS_DPC_PI_FIRST | NVME_NS_DPC_PI_LAST |
+			  NVME_NS_DPC_PI_TYPE1 | NVME_NS_DPC_PI_TYPE2 |
+			  NVME_NS_DPC_PI_TYPE3;
+		id->mc = NVME_NS_MC_META_EXT;
+		id->dps = ns->prot_type;
+		id->flbas = NVME_NS_FLBAS_META_EXT;
+		id->lbaf[0].ms = ns->ms;
+	}
+
 	if (ns->readonly)
 		id->nsattr |= (1 << 0);
 	nvmet_put_namespace(ns);
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 98613a4..316e3c9 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -862,10 +862,34 @@ static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_subsys_, attr_serial);
 
+static ssize_t nvmet_subsys_attr_pi_enable_show(struct config_item *item,
+						char *page)
+{
+	return snprintf(page, PAGE_SIZE, "%d\n", to_subsys(item)->pi_support);
+}
+
+static ssize_t nvmet_subsys_attr_pi_enable_store(struct config_item *item,
+						 const char *page, size_t count)
+{
+	struct nvmet_subsys *subsys = to_subsys(item);
+	bool pi_enable;
+
+	if (strtobool(page, &pi_enable))
+		return -EINVAL;
+
+	down_write(&nvmet_config_sem);
+	subsys->pi_support = pi_enable;
+	up_write(&nvmet_config_sem);
+
+	return count;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_pi_enable);
+
 static struct configfs_attribute *nvmet_subsys_attrs[] = {
 	&nvmet_subsys_attr_attr_allow_any_host,
 	&nvmet_subsys_attr_attr_version,
 	&nvmet_subsys_attr_attr_serial,
+	&nvmet_subsys_attr_attr_pi_enable,
 	NULL,
 };
 
diff --git a/drivers/nvme/target/fabrics-cmd.c b/drivers/nvme/target/fabrics-cmd.c
index ee41b2b..5a99878 100644
--- a/drivers/nvme/target/fabrics-cmd.c
+++ b/drivers/nvme/target/fabrics-cmd.c
@@ -192,6 +192,17 @@ static void nvmet_execute_admin_connect(struct nvmet_req *req)
 		goto out;
 	}
 
+	if (ctrl->subsys->pi_support) {
+		if (ctrl->port->pi_capable) {
+			ctrl->pi_support = true;
+			pr_info("controller %d T10-PI enabled\n", ctrl->cntlid);
+		} else {
+			ctrl->pi_support = false;
+			pr_warn("T10-PI is not supported on controller %d\n",
+				ctrl->cntlid);
+		}
+	}
+
 	uuid_copy(&ctrl->hostid, &d->hostid);
 
 	status = nvmet_install_queue(ctrl, req);
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 574ee55..3d102d6 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -144,6 +144,7 @@ struct nvmet_port {
 	bool				enabled;
 	int				inline_data_size;
 	const struct nvmet_fabrics_ops	*tr_ops;
+	bool				pi_capable;
 };
 
 static inline struct nvmet_port *to_nvmet_port(struct config_item *item)
@@ -203,6 +204,7 @@ struct nvmet_ctrl {
 	spinlock_t		error_lock;
 	u64			err_counter;
 	struct nvme_error_slot	slots[NVMET_ERROR_LOG_SLOTS];
+	bool			pi_support;
 };
 
 struct nvmet_subsys {
@@ -225,6 +227,7 @@ struct nvmet_subsys {
 	u64			ver;
 	u64			serial;
 	char			*subsysnqn;
+	bool			pi_support;
 
 	struct config_group	group;
 
@@ -511,6 +514,8 @@ static inline bool nvmet_ns_has_pi(struct nvmet_ns *ns)
 	return ns->prot_type && ns->ms == sizeof(struct t10_pi_tuple);
 }
 
+#define NVMET_T10_PI_MAX_KB_SZ 128
+
 static inline u32 nvmet_dsm_len(struct nvmet_req *req)
 {
 	return (le32_to_cpu(req->cmd->dsm.nr) + 1) *
-- 
1.8.3.1


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