This patch rejects any new connection to the passthru-ctrl if this
controller is already connected to a different host. At the time of
allocating the controller we check if the subsys associated with
the passthru ctrl is already connected to a host and reject it
if the hostnqn differs.
Connections from the same host (by hostnqn) are supported to allow
for multipath.
[chaitanya.kulkarni@xxxxxxx: based conceptually on a similar patch but
different implementation]
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
---
drivers/nvme/target/core.c | 4 ++++
drivers/nvme/target/io-cmd-passthru.c | 31 +++++++++++++++++++++++++++
drivers/nvme/target/nvmet.h | 7 ++++++
3 files changed, 42 insertions(+)
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 2e75968af7f4..c655f26db3da 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1278,6 +1278,10 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
if (!ctrl->sqs)
goto out_free_cqs;
+ ret = nvmet_passthru_alloc_ctrl(subsys, hostnqn);
+ if (ret)
+ goto out_free_sqs;
+
ret = ida_simple_get(&cntlid_ida,
NVME_CNTLID_MIN, NVME_CNTLID_MAX,
GFP_KERNEL);
diff --git a/drivers/nvme/target/io-cmd-passthru.c b/drivers/nvme/target/io-cmd-passthru.c
index b199785500ad..06a919283cc5 100644
--- a/drivers/nvme/target/io-cmd-passthru.c
+++ b/drivers/nvme/target/io-cmd-passthru.c
@@ -104,6 +104,37 @@ void nvmet_passthru_subsys_free(struct nvmet_subsys *subsys)
mutex_unlock(&subsys->lock);
}
+int nvmet_passthru_alloc_ctrl(struct nvmet_subsys *subsys,
+ const char *hostnqn)
+{
+ struct nvmet_ctrl *ctrl;
+
+ /*
+ * Check here if this subsystem is already connected to the passthru
+ * ctrl. We allow only one host to connect to a given passthru
+ * subsystem.
+ */
+ int rc = 0;
+
+ mutex_lock(&subsys->lock);
+
+ if (!subsys->passthru_ctrl)
+ goto out;
+
+ if (list_empty(&subsys->ctrls))
+ goto out;
+
+ ctrl = list_first_entry(&subsys->ctrls, struct nvmet_ctrl,
+ subsys_entry);
+
+ if (strcmp(hostnqn, ctrl->hostnqn))
+ rc = -ENODEV;
+
+out:
+ mutex_unlock(&subsys->lock);
+ return rc;
+}
+
static void nvmet_passthru_req_complete(struct nvmet_req *req,
struct request *rq, u16 status)
{
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index aff4db03269d..6436cb990905 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -513,6 +513,8 @@ void nvmet_passthru_destroy(void);
void nvmet_passthru_subsys_free(struct nvmet_subsys *subsys);
int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys);
void nvmet_passthru_ctrl_disable(struct nvmet_subsys *subsys);
+int nvmet_passthru_alloc_ctrl(struct nvmet_subsys *subsys,
+ const char *hostnqn);
u16 nvmet_parse_passthru_cmd(struct nvmet_req *req);
static inline
@@ -536,6 +538,11 @@ static inline void nvmet_passthru_subsys_free(struct nvmet_subsys *subsys)
static inline void nvmet_passthru_ctrl_disable(struct nvmet_subsys *subsys)
{
}
+static inline int nvmet_passthru_alloc_ctrl(struct nvmet_subsys *subsys,
+ const char *hostnqn)
+{
+ return 0;
+}
static inline u16 nvmet_parse_passthru_cmd(struct nvmet_req *req)
{
return 0;
--
2.20.1
