[PATCH 0/2] nvmet: make model and ctrl-id configurable

[PATCH 0/2] nvmet: make model and ctrl-id configurable

[Chaitanya Kulkarni]

Hi,

This is a small patch series which allows user to configure the
model and the controller ID.

The changelog is present in the respective patches.

The patch-series for the nvmetcli with new attribute support
will follow this one shortly.

Regards,
Chaitanya

Chaitanya Kulkarni (1):
  nvmet: make ctrl-id configurable

Mark Ruijter (1):
  nvmet: make ctrl model configurable

 drivers/nvme/target/admin-cmd.c |  12 +++-
 drivers/nvme/target/configfs.c  | 115 ++++++++++++++++++++++++++++++++
 drivers/nvme/target/core.c      |  10 ++-
 drivers/nvme/target/nvmet.h     |   6 ++
 4 files changed, 139 insertions(+), 4 deletions(-)

-- 
2.22.1


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[PATCH V2 1/2] nvmet: make ctrl-id configurable

[Chaitanya Kulkarni]

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

For example, when using a cluster setup with two nodes, with a dual
ported NVMe drive and exporting the drive from both the nodes,
The connection to the host fails due to the same controller ID and
results in the following error message:-

"nvme nvmeX: Duplicate cntlid XXX with nvmeX, rejecting"

With this patch now user can partition the controller IDs for each
subsystem by setting up the cntlid_min and cntlid_max. These values
will be used at the time of the controller ID creation. By partitioning
the ctrl-ids for each subsystem results in the unique ctrl-id space
which avoids the collision.

When new attribute is not specified target will fall back to original
cntlid calculation method.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
Changes from V1:-
1. Add cntlid max and min configfs attributes.
2. Use simple if .. else statements instead of ternary operators.
---
 drivers/nvme/target/configfs.c | 65 ++++++++++++++++++++++++++++++++++
 drivers/nvme/target/core.c     |  8 +++--
 drivers/nvme/target/nvmet.h    |  2 ++
 3 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 98613a45bd3b..5316cdb1b271 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -862,10 +862,75 @@ static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_subsys_, attr_serial);
 
+static bool nvmet_subsys_cntlid_store(struct nvmet_subsys *s, const char *page,
+				      bool min)
+{
+	bool ret = true;
+	u16 cid;
+
+	down_write(&nvmet_config_sem);
+	if (sscanf(page, "%hu\n", &cid) != 1) {
+		ret = false;
+		goto out;
+	}
+
+	if (min)
+		s->cntlid_min = cid;
+	else
+		s->cntlid_max = cid;
+out:
+	up_write(&nvmet_config_sem);
+
+	return ret;
+}
+
+static ssize_t nvmet_subsys_cntlid_show(struct nvmet_subsys *s, char *page,
+					bool min)
+{
+	if (min)
+		return snprintf(page, PAGE_SIZE, "%u\n", s->cntlid_min);
+
+	return snprintf(page, PAGE_SIZE, "%u\n",  s->cntlid_max);
+}
+
+static ssize_t nvmet_subsys_attr_cntlid_min_show(struct config_item *item,
+						 char *page)
+{
+	return nvmet_subsys_cntlid_show(to_subsys(item), page, true);
+}
+
+static ssize_t nvmet_subsys_attr_cntlid_min_store(struct config_item *item,
+						  const char *page, size_t cnt)
+{
+	if (!nvmet_subsys_cntlid_store(to_subsys(item), page, true))
+		return -EINVAL;
+
+	return cnt;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_cntlid_min);
+
+static ssize_t nvmet_subsys_attr_cntlid_max_show(struct config_item *item,
+						 char *page)
+{
+	return nvmet_subsys_cntlid_show(to_subsys(item), page, false);
+}
+
+static ssize_t nvmet_subsys_attr_cntlid_max_store(struct config_item *item,
+						  const char *page, size_t cnt)
+{
+	if (!nvmet_subsys_cntlid_store(to_subsys(item), page, false))
+		return -EINVAL;
+
+	return cnt;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_cntlid_max);
+
 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_cntlid_min,
+	&nvmet_subsys_attr_attr_cntlid_max,
 	NULL,
 };
 
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 28438b833c1b..990ad4c7bdfd 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1267,8 +1267,11 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 	if (!ctrl->sqs)
 		goto out_free_cqs;
 
+	if (subsys->cntlid_min > subsys->cntlid_max)
+		goto out_free_cqs;
+
 	ret = ida_simple_get(&cntlid_ida,
-			     NVME_CNTLID_MIN, NVME_CNTLID_MAX,
+			     subsys->cntlid_min, subsys->cntlid_max,
 			     GFP_KERNEL);
 	if (ret < 0) {
 		status = NVME_SC_CONNECT_CTRL_BUSY | NVME_SC_DNR;
@@ -1416,7 +1419,8 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 		kfree(subsys);
 		return ERR_PTR(-ENOMEM);
 	}
-
+	subsys->cntlid_min = NVME_CNTLID_MIN;
+	subsys->cntlid_max = NVME_CNTLID_MAX;
 	kref_init(&subsys->ref);
 
 	mutex_init(&subsys->lock);
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 46df45e837c9..6492d12e626a 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -211,6 +211,8 @@ struct nvmet_subsys {
 	struct list_head	namespaces;
 	unsigned int		nr_namespaces;
 	unsigned int		max_nsid;
+	u16			cntlid_min;
+	u16			cntlid_max;
 
 	struct list_head	ctrls;
 
-- 
2.22.1


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[PATCH V3 2/2] nvmet: make ctrl model configurable

[Chaitanya Kulkarni]

From: Mark Ruijter <MRuijter@onestopsystems.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>
---
Changes from V2:-

1. Use if else pattern than ternary operators.
2. Change the name nvmet_subsys_model() -> nvmet_model_number().
3. Introduce nvmet_is_ascii() to filter the model characters.
4. Change tmp -> tmp_model in nvmet_subsys_attr_model_store().

Changes from V1:-

1. Don't allocate memory for default subsys model,
2. Use helper to get the default model string from ctrl->subsys in the
   nvmet_execute_identify_ctrl() and nvmet_subsys_attr_model()_show.
   Later is needed so that nvmetcli can display default value Linux
   when the model is not set from the user.
3. Get rid of the extra variable c in the nvmet_subsys_attr_model_store()
   and replace for with while loop without loosing the code redability.
---
 drivers/nvme/target/admin-cmd.c | 12 ++++++--
 drivers/nvme/target/configfs.c  | 50 +++++++++++++++++++++++++++++++++
 drivers/nvme/target/core.c      |  2 ++
 drivers/nvme/target/nvmet.h     |  4 +++
 4 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 56c21b501185..613e715dc7d3 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -312,12 +312,20 @@ static void nvmet_execute_get_log_page(struct nvmet_req *req)
 	nvmet_req_complete(req, NVME_SC_INVALID_FIELD | NVME_SC_DNR);
 }
 
+const char *nvmet_model_number(struct nvmet_subsys *subsys)
+{
+	if (subsys->model)
+		return subsys->model;
+
+	return NVMET_DEFAULT_CTRL_MODEL;
+}
+
 static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 {
+	const char *model = nvmet_model_number(req->sq->ctrl->subsys);
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	struct nvme_id_ctrl *id;
 	u16 status = 0;
-	const char model[] = "Linux";
 
 	id = kzalloc(sizeof(*id), GFP_KERNEL);
 	if (!id) {
@@ -332,7 +340,7 @@ 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 5316cdb1b271..00869b805c6b 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -925,12 +925,62 @@ static ssize_t nvmet_subsys_attr_cntlid_max_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_subsys_, attr_cntlid_max);
 
+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",
+			nvmet_model_number(subsys));
+}
+
+/* See Section 1.5 of NVMe 1.4 */
+static bool nvmet_is_ascii(const char c)
+{
+	return c >= 0x20 && c <= 0x7e;
+}
+
+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 = 0, len;
+	char *tmp_model;
+
+	down_write(&nvmet_config_sem);
+	len = strcspn(page, "\n");
+	if (!len)
+		goto out_unlock;
+
+	for (pos = 0; pos < len; pos++) {
+		if (!nvmet_is_ascii(page[pos]))
+			goto out_unlock;
+	}
+
+	tmp_model = kstrndup(page, len, GFP_KERNEL);
+	if (!tmp_model) {
+		ret = -ENOMEM;
+		goto out_unlock;
+	}
+
+	ret = count;
+	kfree(subsys->model);
+	subsys->model = tmp_model;
+
+out_unlock:
+	up_write(&nvmet_config_sem);
+	return ret;
+}
+
+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_cntlid_min,
 	&nvmet_subsys_attr_attr_cntlid_max,
+	&nvmet_subsys_attr_attr_model,
 	NULL,
 };
 
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 990ad4c7bdfd..a985ca7febd5 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1419,6 +1419,7 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 		kfree(subsys);
 		return ERR_PTR(-ENOMEM);
 	}
+	subsys->model = NULL;
 	subsys->cntlid_min = NVME_CNTLID_MIN;
 	subsys->cntlid_max = NVME_CNTLID_MAX;
 	kref_init(&subsys->ref);
@@ -1439,6 +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 6492d12e626a..c54ce5f66f09 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:
@@ -224,6 +225,7 @@ struct nvmet_subsys {
 	u64			ver;
 	u64			serial;
 	char			*subsysnqn;
+	char			*model;
 
 	struct config_group	group;
 
@@ -489,6 +491,8 @@ u16 nvmet_bdev_flush(struct nvmet_req *req);
 u16 nvmet_file_flush(struct nvmet_req *req);
 void nvmet_ns_changed(struct nvmet_subsys *subsys, u32 nsid);
 
+const char *nvmet_model_number(struct nvmet_subsys *subsys);
+
 static inline u32 nvmet_rw_len(struct nvmet_req *req)
 {
 	return ((u32)le16_to_cpu(req->cmd->rw.length) + 1) <<
-- 
2.22.1


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Re: [PATCH V2 1/2] nvmet: make ctrl-id configurable

[Christoph Hellwig]

On Thu, Nov 21, 2019 at 11:41:53PM -0800, Chaitanya Kulkarni wrote:
> This patch adds a new target subsys attribute which allows user to
> optionally specify target controller IDs which then used in the
> nvmet_execute_identify_ctrl() to fill up the nvme_id_ctrl structure.
> 
> For example, when using a cluster setup with two nodes, with a dual
> ported NVMe drive and exporting the drive from both the nodes,
> The connection to the host fails due to the same controller ID and
> results in the following error message:-
> 
> "nvme nvmeX: Duplicate cntlid XXX with nvmeX, rejecting"
> 
> With this patch now user can partition the controller IDs for each
> subsystem by setting up the cntlid_min and cntlid_max. These values
> will be used at the time of the controller ID creation. By partitioning
> the ctrl-ids for each subsystem results in the unique ctrl-id space
> which avoids the collision.
> 
> When new attribute is not specified target will fall back to original
> cntlid calculation method.
> 
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
> ---
> Changes from V1:-
> 1. Add cntlid max and min configfs attributes.
> 2. Use simple if .. else statements instead of ternary operators.
> ---
>  drivers/nvme/target/configfs.c | 65 ++++++++++++++++++++++++++++++++++
>  drivers/nvme/target/core.c     |  8 +++--
>  drivers/nvme/target/nvmet.h    |  2 ++
>  3 files changed, 73 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
> index 98613a45bd3b..5316cdb1b271 100644
> --- a/drivers/nvme/target/configfs.c
> +++ b/drivers/nvme/target/configfs.c
> @@ -862,10 +862,75 @@ static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item,
>  }
>  CONFIGFS_ATTR(nvmet_subsys_, attr_serial);
>  
> +static bool nvmet_subsys_cntlid_store(struct nvmet_subsys *s, const char *page,
> +				      bool min)
> +{
> +	bool ret = true;
> +	u16 cid;
> +
> +	down_write(&nvmet_config_sem);
> +	if (sscanf(page, "%hu\n", &cid) != 1) {
> +		ret = false;
> +		goto out;
> +	}

No need to take the lock over the sscant.  That also means you can
directly return false here and don't need the ret variable or the
out label.  Also the rest of the function is so simple that I'd rather
duplicate it over the slightly confusing min parameter.

> +static ssize_t nvmet_subsys_cntlid_show(struct nvmet_subsys *s, char *page,
> +					bool min)
> +{
> +	if (min)
> +		return snprintf(page, PAGE_SIZE, "%u\n", s->cntlid_min);
> +
> +	return snprintf(page, PAGE_SIZE, "%u\n",  s->cntlid_max);

Just opencode the snprints in the two callers, which is going to
be much simpler.

> index 28438b833c1b..990ad4c7bdfd 100644
> --- a/drivers/nvme/target/core.c
> +++ b/drivers/nvme/target/core.c
> @@ -1267,8 +1267,11 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
>  	if (!ctrl->sqs)
>  		goto out_free_cqs;
>  
> +	if (subsys->cntlid_min > subsys->cntlid_max)
> +		goto out_free_cqs;

Shouldn't this check go into the store functions?

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Re: [PATCH V3 2/2] nvmet: make ctrl model configurable

[Christoph Hellwig]

On Thu, Nov 21, 2019 at 11:41:54PM -0800, Chaitanya Kulkarni wrote:
> From: Mark Ruijter <MRuijter@onestopsystems.com>
> 
> From: Mark Ruijter <MRuijter@onestopsystems.com>

That From line seems duplicated.

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

Please add a very short summary of what you changed in [] braces
before your signoff.

> +	down_write(&nvmet_config_sem);
> +	len = strcspn(page, "\n");
> +	if (!len)
> +		goto out_unlock;

No need for the lock until we free the old subsys->model and
assign the new one.  Which will again simplify the error handling.

> +++ b/drivers/nvme/target/core.c
> @@ -1419,6 +1419,7 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
>  		kfree(subsys);
>  		return ERR_PTR(-ENOMEM);
>  	}
> +	subsys->model = NULL;

subsys is allocated using kzalloc a few lines above, no need to zero
->model.

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