[PATCH] nvmet: make ctrl model configurable

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

This patch adds a new target subsys attribute which allows user to
optionally specify model name which then used in the
nvmet_execute_identify_ctrl() to fill up the nvme_id_ctrl structure.

Default value for the model is set to "Linux".

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/nvme/target/admin-cmd.c |  4 ++--
 drivers/nvme/target/configfs.c  | 29 +++++++++++++++++++++++++++++
 drivers/nvme/target/core.c      |  6 ++++++
 drivers/nvme/target/nvmet.h     |  2 ++
 4 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 56c21b501185..917d8f3fded7 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -315,9 +315,9 @@ static void nvmet_execute_get_log_page(struct nvmet_req *req)
 static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 {
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+	const char *model = ctrl->subsys->model;
 	struct nvme_id_ctrl *id;
 	u16 status = 0;
-	const char model[] = "Linux";
 
 	id = kzalloc(sizeof(*id), GFP_KERNEL);
 	if (!id) {
@@ -332,7 +332,7 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 	memset(id->sn, ' ', sizeof(id->sn));
 	bin2hex(id->sn, &ctrl->subsys->serial,
 		min(sizeof(ctrl->subsys->serial), sizeof(id->sn) / 2));
-	memcpy_and_pad(id->mn, sizeof(id->mn), model, sizeof(model) - 1, ' ');
+	memcpy_and_pad(id->mn, sizeof(id->mn), model, strlen(model), ' ');
 	memcpy_and_pad(id->fr, sizeof(id->fr),
 		       UTS_RELEASE, strlen(UTS_RELEASE), ' ');
 
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 98613a45bd3b..e91ebe74c938 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -862,10 +862,39 @@ static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_subsys_, attr_serial);
 
+static ssize_t nvmet_subsys_attr_model_show(struct config_item *item,
+					     char *page)
+{
+	struct nvmet_subsys *subsys = to_subsys(item);
+
+	return snprintf(page, PAGE_SIZE, "%s\n", subsys->model);
+}
+
+static ssize_t nvmet_subsys_attr_model_store(struct config_item *item,
+					     const char *page, size_t count)
+{
+	struct nvmet_subsys *subsys = to_subsys(item);
+	int ret = 0;
+
+	down_write(&nvmet_config_sem);
+	kfree(subsys->model);
+	subsys->model = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!subsys->model)
+		ret = -ENOMEM;
+	else
+		sscanf(page, "%s\n", subsys->model);
+	up_write(&nvmet_config_sem);
+
+	return ret ? ret : count;
+}
+
+CONFIGFS_ATTR(nvmet_subsys_, attr_model);
+
 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_model,
 	NULL,
 };
 
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 28438b833c1b..d3e2a1f58a93 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1394,6 +1394,11 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 		return ERR_PTR(-ENOMEM);
 
 	subsys->ver = NVME_VS(1, 3, 0); /* NVMe 1.3.0 */
+
+	subsys->model = kstrdup(NVMET_DEFAULT_CTRL_MODEL, GFP_KERNEL);
+	if (!subsys->model)
+		return ERR_PTR(-ENOMEM);
+
 	/* generate a random serial number as our controllers are ephemeral: */
 	get_random_bytes(&subsys->serial, sizeof(subsys->serial));
 
@@ -1435,6 +1440,7 @@ static void nvmet_subsys_free(struct kref *ref)
 	WARN_ON_ONCE(!list_empty(&subsys->namespaces));
 
 	kfree(subsys->subsysnqn);
+	kfree(subsys->model);
 	kfree(subsys);
 }
 
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 46df45e837c9..d5fcfd09658e 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -23,6 +23,7 @@
 #define NVMET_ASYNC_EVENTS		4
 #define NVMET_ERROR_LOG_SLOTS		128
 #define NVMET_NO_ERROR_LOC		((u16)-1)
+#define NVMET_DEFAULT_CTRL_MODEL	"Linux"
 
 /*
  * Supported optional AENs:
@@ -227,6 +228,7 @@ struct nvmet_subsys {
 
 	struct config_group	namespaces_group;
 	struct config_group	allowed_hosts_group;
+	char			*model;
 };
 
 static inline struct nvmet_subsys *to_subsys(struct config_item *item)
-- 
2.22.1


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