[PATCH] nvmet: make ctrl model configurable

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

From: Mark Ruijter <MRuijter@onestopsystems.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.

The default value for the model is set to "Linux" for backward
compatibility.

Signed-off-by: Mark Ruijter <MRuijter@onestopsystems.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
Hi,

This patch is originally posted by Mark and later same day by me with
the same concept. I've merged changes from both patch into one and
cleaned the code to fit the kernel coding standards.

-Regards,
Chaitanya
---
 drivers/nvme/target/admin-cmd.c |  4 +--
 drivers/nvme/target/configfs.c  | 45 +++++++++++++++++++++++++++++++++
 drivers/nvme/target/core.c      |  7 +++++
 drivers/nvme/target/nvmet.h     |  2 ++
 4 files changed, 56 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..faf34b15b975 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -862,10 +862,54 @@ 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 = -EINVAL, pos, len;
+	char c;
+
+	down_write(&nvmet_config_sem);
+	len = strcspn(page, "\n");
+	if (!len) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	/* Only 20h (space) until 7eh (~) is allowed */
+	for (pos = 0; pos < len; pos++) {
+		c = page[pos];
+		if (c < 0x20 || c > 0x7e) {
+			ret = -EINVAL;
+			goto out_unlock;
+		}
+	}
+
+	kfree(subsys->model);
+	subsys->model = kstrndup(page, len, GFP_KERNEL);
+	if (!subsys->model)
+		ret = -ENOMEM;
+
+out_unlock:
+	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,
 };
 
@@ -901,6 +945,7 @@ static struct config_group *nvmet_subsys_make(struct config_group *group,
 	}
 
 	subsys = nvmet_subsys_alloc(name, NVME_NQN_NVME);
+	subsys->model = kstrdup(NVMET_DEFAULT_CTRL_MODEL, GFP_KERNEL);
 	if (IS_ERR(subsys))
 		return ERR_CAST(subsys);
 
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 28438b833c1b..adc1eb667601 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1416,6 +1416,12 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 		kfree(subsys);
 		return ERR_PTR(-ENOMEM);
 	}
+	subsys->model = kstrdup(NVMET_DEFAULT_CTRL_MODEL, GFP_KERNEL);
+	if (!subsys->model) {
+		kfree(subsys->subsysnqn);
+		kfree(subsys);
+		return ERR_PTR(-ENOMEM);
+	}
 
 	kref_init(&subsys->ref);
 
@@ -1435,6 +1441,7 @@ 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..afb6116de892 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:
@@ -222,6 +223,7 @@ struct nvmet_subsys {
 	u64			ver;
 	u64			serial;
 	char			*subsysnqn;
+	char			*model;
 
 	struct config_group	group;
 
-- 
2.22.1


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