[PATCH V12 1/3] nvmet: add NVM Command Set Identifier support

[Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>]

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 a 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
supports default command set identifier. We update the namespace data
structure to store the CSI value which defaults to NVME_CSI_NVM
that represents traditional logical blocks namespace type.

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

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/nvme/target/admin-cmd.c | 47 +++++++++++++++++++++++++++------
 drivers/nvme/target/core.c      | 16 ++++++++++-
 drivers/nvme/target/nvmet.h     |  1 +
 include/linux/nvme.h            |  1 +
 4 files changed, 56 insertions(+), 9 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index f4cc32674edd..176c8593d341 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -162,15 +162,8 @@ static void nvmet_execute_get_log_page_smart(struct nvmet_req *req)
 	nvmet_req_complete(req, status);
 }
 
-static void nvmet_execute_get_log_cmd_effects_ns(struct nvmet_req *req)
+static void nvmet_set_csi_nvm_effects(struct nvme_effects_log *log)
 {
-	u16 status = NVME_SC_INTERNAL;
-	struct nvme_effects_log *log;
-
-	log = kzalloc(sizeof(*log), GFP_KERNEL);
-	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);
@@ -184,9 +177,31 @@ static void nvmet_execute_get_log_cmd_effects_ns(struct nvmet_req *req)
 	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);
+}
+
+static void nvmet_execute_get_log_cmd_effects_ns(struct nvmet_req *req)
+{
+	struct nvme_effects_log *log;
+	u16 status = NVME_SC_SUCCESS;
+
+	log = kzalloc(sizeof(*log), GFP_KERNEL);
+	if (!log) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	switch (req->cmd->get_log_page.csi) {
+	case NVME_CSI_NVM:
+		nvmet_set_csi_nvm_effects(log);
+		break;
+	default:
+		status = NVME_SC_INVALID_LOG_PAGE;
+		goto free;
+	}
 
 	status = nvmet_copy_to_sgl(req, 0, log, sizeof(*log));
 
+free:
 	kfree(log);
 out:
 	nvmet_req_complete(req, status);
@@ -611,6 +626,18 @@ static u16 nvmet_copy_ns_identifier(struct nvmet_req *req, u8 type, u8 len,
 	return 0;
 }
 
+static u16 nvmet_execute_identify_desclist_csi(struct nvmet_req *req, off_t *o)
+{
+	switch (req->ns->csi) {
+	case NVME_CSI_NVM:
+		return nvmet_copy_ns_identifier(req, NVME_NIDT_CSI,
+						NVME_NIDT_CSI_LEN,
+						&req->ns->csi, o);
+	}
+
+	return NVME_SC_INVALID_IO_CMD_SET;
+}
+
 static void nvmet_execute_identify_desclist(struct nvmet_req *req)
 {
 	off_t off = 0;
@@ -635,6 +662,10 @@ static void nvmet_execute_identify_desclist(struct nvmet_req *req)
 			goto out;
 	}
 
+	status = nvmet_execute_identify_desclist_csi(req, &off);
+	if (status)
+		goto out;
+
 	if (sg_zero_buffer(req->sg, req->sg_cnt, NVME_IDENTIFY_DATA_SIZE - off,
 			off) != NVME_IDENTIFY_DATA_SIZE - off)
 		status = NVME_SC_INTERNAL | NVME_SC_DNR;
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index adbede9ab7f3..4abe0b542c96 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -693,6 +693,7 @@ 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;
 }
@@ -1113,6 +1114,17 @@ 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:
+	case NVME_CC_CSS_CSI:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
 {
 	lockdep_assert_held(&ctrl->lock);
@@ -1121,7 +1133,7 @@ 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;
 	}
@@ -1172,6 +1184,8 @@ static void nvmet_init_cap(struct nvmet_ctrl *ctrl)
 {
 	/* command sets supported: NVMe command set: */
 	ctrl->cap = (1ULL << 37);
+	/* Controller supports one or more I/O Command Sets */
+	ctrl->cap |= (1ULL << 43);
 	/* CC.EN timeout in 500msec units: */
 	ctrl->cap |= (15ULL << 24);
 	/* maximum queue entries supported: */
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 24e261bf153a..ee5999920155 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)
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index b08787cd0881..f09fbbb7876b 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -1494,6 +1494,7 @@ enum {
 	NVME_SC_NS_WRITE_PROTECTED	= 0x20,
 	NVME_SC_CMD_INTERRUPTED		= 0x21,
 	NVME_SC_TRANSIENT_TR_ERR	= 0x22,
+	NVME_SC_INVALID_IO_CMD_SET	= 0x2C,
 
 	NVME_SC_LBA_RANGE		= 0x80,
 	NVME_SC_CAP_EXCEEDED		= 0x81,
-- 
2.22.1


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