nvmet: Add passthru enable/disable helpers

This patch adds helper functions which are used in the NVMeOF configfs
when the user is configuring the passthru subsystem. Here we ensure
that only one subsys is assigned to each nvme_ctrl by using an xarray
on the cntlid.

The subsystem's version number is overridden by the passed through
controller's version. However, if that version is less than 1.2.1,
then we bump the advertised version to that and print a warning
in dmesg.

Based-on-a-patch-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index cdec47de89edf027c37781ffe3c86053fe0bbb07..61c258dea88ac170ba43c30442affb11e9098ef7 100644 (file)
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -879,6 +879,10 @@ static ssize_t nvmet_subsys_attr_version_store(struct config_item *item,
        int major, minor, tertiary = 0;
        int ret;
 
+       /* passthru subsystems use the underlying controller's version */
+       if (nvmet_passthru_ctrl(subsys))
+               return -EINVAL;
+
        ret = sscanf(page, "%d.%d.%d\n", &major, &minor, &tertiary);
        if (ret != 2 && ret != 3)
                return -EINVAL;

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index c5a1c82e699b5fc839429043b6ce1006752513de..b92f45f5cd5b1675d5c9190a0e59c694432e5ed6 100644 (file)
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -544,6 +544,12 @@ int nvmet_ns_enable(struct nvmet_ns *ns)
 
        mutex_lock(&subsys->lock);
        ret = 0;
+
+       if (nvmet_passthru_ctrl(subsys)) {
+               pr_info("cannot enable both passthru and regular namespaces for a single subsystem");
+               goto out_unlock;
+       }
+
        if (ns->enabled)
                goto out_unlock;
 
@@ -1473,7 +1479,7 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
        if (!subsys)
                return ERR_PTR(-ENOMEM);
 
-       subsys->ver = NVME_VS(1, 3, 0); /* NVMe 1.3.0 */
+       subsys->ver = NVMET_DEFAULT_VS;
        /* generate a random serial number as our controllers are ephemeral: */
        get_random_bytes(&subsys->serial, sizeof(subsys->serial));
 
@@ -1516,6 +1522,8 @@ static void nvmet_subsys_free(struct kref *ref)
        WARN_ON_ONCE(!xa_empty(&subsys->namespaces));
 
        xa_destroy(&subsys->namespaces);
+       nvmet_passthru_subsys_free(subsys);
+
        kfree(subsys->subsysnqn);
        kfree_rcu(subsys->model, rcuhead);
        kfree(subsys);

diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 51719dc620838569c8eff88b9e1bd876b2aa1b56..9d0aa6560c0c753330ce3d604d90fdb54b3af04e 100644 (file)
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -21,6 +21,8 @@
 #include <linux/radix-tree.h>
 #include <linux/t10-pi.h>
 
+#define NVMET_DEFAULT_VS               NVME_VS(1, 3, 0)
+
 #define NVMET_ASYNC_EVENTS             4
 #define NVMET_ERROR_LOG_SLOTS          128
 #define NVMET_NO_ERROR_LOC             ((u16)-1)
@@ -245,6 +247,7 @@ struct nvmet_subsys {
 
 #ifdef CONFIG_NVME_TARGET_PASSTHRU
        struct nvme_ctrl        *passthru_ctrl;
+       char                    *passthru_ctrl_path;
 #endif /* CONFIG_NVME_TARGET_PASSTHRU */
 };
 
@@ -544,6 +547,9 @@ static inline u32 nvmet_dsm_len(struct nvmet_req *req)
 }
 
 #ifdef CONFIG_NVME_TARGET_PASSTHRU
+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);
 u16 nvmet_parse_passthru_admin_cmd(struct nvmet_req *req);
 u16 nvmet_parse_passthru_io_cmd(struct nvmet_req *req);
 static inline struct nvme_ctrl *nvmet_passthru_ctrl(struct nvmet_subsys *subsys)
@@ -551,6 +557,12 @@ static inline struct nvme_ctrl *nvmet_passthru_ctrl(struct nvmet_subsys *subsys)
        return subsys->passthru_ctrl;
 }
 #else /* CONFIG_NVME_TARGET_PASSTHRU */
+static inline void nvmet_passthru_subsys_free(struct nvmet_subsys *subsys)
+{
+}
+static inline void nvmet_passthru_ctrl_disable(struct nvmet_subsys *subsys)
+{
+}
 static inline u16 nvmet_parse_passthru_admin_cmd(struct nvmet_req *req)
 {
        return 0;

diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
index b9727553ab300adf7788badf66f928f61390626b..89d91dc999a6db57ca56fdc561d84aa51a42ae02 100644 (file)
--- a/drivers/nvme/target/passthru.c
+++ b/drivers/nvme/target/passthru.c
@@ -15,6 +15,11 @@
 
 MODULE_IMPORT_NS(NVME_TARGET_PASSTHRU);
 
+/*
+ * xarray to maintain one passthru subsystem per nvme controller.
+ */
+static DEFINE_XARRAY(passthru_subsystems);
+
 static u16 nvmet_passthru_override_id_ctrl(struct nvmet_req *req)
 {
        struct nvmet_ctrl *ctrl = req->sq->ctrl;
@@ -456,3 +461,84 @@ u16 nvmet_parse_passthru_admin_cmd(struct nvmet_req *req)
                return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
        }
 }
+
+int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys)
+{
+       struct nvme_ctrl *ctrl;
+       int ret = -EINVAL;
+       void *old;
+
+       mutex_lock(&subsys->lock);
+       if (!subsys->passthru_ctrl_path)
+               goto out_unlock;
+       if (subsys->passthru_ctrl)
+               goto out_unlock;
+
+       if (subsys->nr_namespaces) {
+               pr_info("cannot enable both passthru and regular namespaces for a single subsystem");
+               goto out_unlock;
+       }
+
+       ctrl = nvme_ctrl_get_by_path(subsys->passthru_ctrl_path);
+       if (IS_ERR(ctrl)) {
+               ret = PTR_ERR(ctrl);
+               pr_err("failed to open nvme controller %s\n",
+                      subsys->passthru_ctrl_path);
+
+               goto out_unlock;
+       }
+
+       old = xa_cmpxchg(&passthru_subsystems, ctrl->cntlid, NULL,
+                        subsys, GFP_KERNEL);
+       if (xa_is_err(old)) {
+               ret = xa_err(old);
+               goto out_put_ctrl;
+       }
+
+       if (old)
+               goto out_put_ctrl;
+
+       subsys->passthru_ctrl = ctrl;
+       subsys->ver = ctrl->vs;
+
+       if (subsys->ver < NVME_VS(1, 2, 1)) {
+               pr_warn("nvme controller version is too old: %llu.%llu.%llu, advertising 1.2.1\n",
+                       NVME_MAJOR(subsys->ver), NVME_MINOR(subsys->ver),
+                       NVME_TERTIARY(subsys->ver));
+               subsys->ver = NVME_VS(1, 2, 1);
+       }
+
+       mutex_unlock(&subsys->lock);
+       return 0;
+
+out_put_ctrl:
+       nvme_put_ctrl(ctrl);
+out_unlock:
+       mutex_unlock(&subsys->lock);
+       return ret;
+}
+
+static void __nvmet_passthru_ctrl_disable(struct nvmet_subsys *subsys)
+{
+       if (subsys->passthru_ctrl) {
+               xa_erase(&passthru_subsystems, subsys->passthru_ctrl->cntlid);
+               nvme_put_ctrl(subsys->passthru_ctrl);
+       }
+       subsys->passthru_ctrl = NULL;
+       subsys->ver = NVMET_DEFAULT_VS;
+}
+
+void nvmet_passthru_ctrl_disable(struct nvmet_subsys *subsys)
+{
+       mutex_lock(&subsys->lock);
+       __nvmet_passthru_ctrl_disable(subsys);
+       mutex_unlock(&subsys->lock);
+}
+
+void nvmet_passthru_subsys_free(struct nvmet_subsys *subsys)
+{
+       mutex_lock(&subsys->lock);
+       __nvmet_passthru_ctrl_disable(subsys);
+       mutex_unlock(&subsys->lock);
+       kfree(subsys->passthru_ctrl_path);
+}