[PATCH V8 3/9] nvmet: add NVM command set identifier support

[Chaitanya Kulkarni]

NVMe TP 4056 allows controller to support different command sets.
NVMeoF target currently only supports namespaces that contain
traditional logical blocks that may be randomly read and written. In
some applications there is value in exposing namespaces that contain
logical blocks that have special access rules (e.g. sequentially write
required namespace such as Zoned Namespace (ZNS)).

In order to support the Zoned Block Devices (ZBD) backend, controller
needs to have support for ZNS Command Set Identifier (CSI).

In this preparation patch, we adjust the code such that it can now 
support different command sets. We update the namespace data
structure to store the CSI value which defaults to NVME_CSI_NVM
which represents traditional logical blocks namespace type.

The CSI support is required to implement the ZBD backend over NVMe ZNS 
interface, since ZNS commands belongs to the different command set than
the default one.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
---
 drivers/nvme/target/admin-cmd.c | 33 ++++++++++++++++++++-------------
 drivers/nvme/target/core.c      | 13 ++++++++++++-
 drivers/nvme/target/nvmet.h     |  1 +
 3 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 220edacfccfb..2e865bff893f 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -175,19 +175,26 @@ static void nvmet_execute_get_log_cmd_effects_ns(struct nvmet_req *req)
 	if (!log)
 		goto out;
 
-	log->acs[nvme_admin_get_log_page]	= cpu_to_le32(1 << 0);
-	log->acs[nvme_admin_identify]		= cpu_to_le32(1 << 0);
-	log->acs[nvme_admin_abort_cmd]		= cpu_to_le32(1 << 0);
-	log->acs[nvme_admin_set_features]	= cpu_to_le32(1 << 0);
-	log->acs[nvme_admin_get_features]	= cpu_to_le32(1 << 0);
-	log->acs[nvme_admin_async_event]	= cpu_to_le32(1 << 0);
-	log->acs[nvme_admin_keep_alive]		= cpu_to_le32(1 << 0);
-
-	log->iocs[nvme_cmd_read]		= cpu_to_le32(1 << 0);
-	log->iocs[nvme_cmd_write]		= cpu_to_le32(1 << 0);
-	log->iocs[nvme_cmd_flush]		= cpu_to_le32(1 << 0);
-	log->iocs[nvme_cmd_dsm]			= cpu_to_le32(1 << 0);
-	log->iocs[nvme_cmd_write_zeroes]	= cpu_to_le32(1 << 0);
+	switch (req->cmd->get_log_page.csi) {
+	case NVME_CSI_NVM:
+		log->acs[nvme_admin_get_log_page]	= cpu_to_le32(1 << 0);
+		log->acs[nvme_admin_identify]		= cpu_to_le32(1 << 0);
+		log->acs[nvme_admin_abort_cmd]		= cpu_to_le32(1 << 0);
+		log->acs[nvme_admin_set_features]	= cpu_to_le32(1 << 0);
+		log->acs[nvme_admin_get_features]	= cpu_to_le32(1 << 0);
+		log->acs[nvme_admin_async_event]	= cpu_to_le32(1 << 0);
+		log->acs[nvme_admin_keep_alive]		= cpu_to_le32(1 << 0);
+
+		log->iocs[nvme_cmd_read]		= cpu_to_le32(1 << 0);
+		log->iocs[nvme_cmd_write]		= cpu_to_le32(1 << 0);
+		log->iocs[nvme_cmd_flush]		= cpu_to_le32(1 << 0);
+		log->iocs[nvme_cmd_dsm]			= cpu_to_le32(1 << 0);
+		log->iocs[nvme_cmd_write_zeroes]	= cpu_to_le32(1 << 0);
+		break;
+	default:
+		status = NVME_SC_INVALID_LOG_PAGE;
+		break;
+	}
 
 	status = nvmet_copy_to_sgl(req, 0, log, sizeof(*log));
 
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 8ce4d59cc9e7..672e4009f8d6 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -681,6 +681,7 @@ struct nvmet_ns *nvmet_ns_alloc(struct nvmet_subsys *subsys, u32 nsid)
 
 	uuid_gen(&ns->uuid);
 	ns->buffered_io = false;
+	ns->csi = NVME_CSI_NVM;
 
 	return ns;
 }
@@ -1103,6 +1104,16 @@ static inline u8 nvmet_cc_iocqes(u32 cc)
 	return (cc >> NVME_CC_IOCQES_SHIFT) & 0xf;
 }
 
+static inline bool nvmet_cc_css_check(u8 cc_css)
+{
+	switch (cc_css <<= NVME_CC_CSS_SHIFT) {
+	case NVME_CC_CSS_NVM:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
 {
 	lockdep_assert_held(&ctrl->lock);
@@ -1111,7 +1122,7 @@ static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
 	    nvmet_cc_iocqes(ctrl->cc) != NVME_NVM_IOCQES ||
 	    nvmet_cc_mps(ctrl->cc) != 0 ||
 	    nvmet_cc_ams(ctrl->cc) != 0 ||
-	    nvmet_cc_css(ctrl->cc) != 0) {
+	    !nvmet_cc_css_check(nvmet_cc_css(ctrl->cc))) {
 		ctrl->csts = NVME_CSTS_CFS;
 		return;
 	}
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 8776dd1a0490..476b3cd91c65 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -81,6 +81,7 @@ struct nvmet_ns {
 	struct pci_dev		*p2p_dev;
 	int			pi_type;
 	int			metadata_size;
+	u8			csi;
 };
 
 static inline struct nvmet_ns *to_nvmet_ns(struct config_item *item)
-- 
2.22.1