lightnvm: control life of nvm_dev in driver

LightNVM compatible device drivers does not have a method to expose
LightNVM specific sysfs entries.

To enable LightNVM sysfs entries to be exposed, lightnvm device
drivers require a struct device to attach it to. To allow both the
actual device driver and lightnvm sysfs entries to coexist, the device
driver tracks the lifetime of the nvm_dev structure.

This patch refactors NVMe and null_blk to handle the lifetime of struct
nvm_dev, which eliminates the need for struct gendisk when a lightnvm
compatible device is provided.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 8 insertions, 27 deletions

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 25c5df920326..a99b59d1eb36 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -660,22 +660,15 @@ static void nvm_exit(struct nvm_dev *dev)
         pr_info("nvm: successfully unloaded\n");
 }
 
-int nvm_register(struct request_queue *q, char *disk_name,
-                                                        struct nvm_dev_ops *ops)
+struct nvm_dev *nvm_alloc_dev(int node)
 {
-        struct nvm_dev *dev;
-        int ret;
-
-        if (!ops->identity)
-                return -EINVAL;
-
-        dev = kzalloc(sizeof(struct nvm_dev), GFP_KERNEL);
-        if (!dev)
-                return -ENOMEM;
+        return kzalloc_node(sizeof(struct nvm_dev), GFP_KERNEL, node);
+}
+EXPORT_SYMBOL(nvm_alloc_dev);
 
-        dev->q = q;
-        dev->ops = ops;
-        strncpy(dev->name, disk_name, DISK_NAME_LEN);
+int nvm_register(struct nvm_dev *dev)
+{
+        int ret;
 
         ret = nvm_init(dev);
         if (ret)
@@ -714,29 +707,17 @@ int nvm_register(struct request_queue *q, char *disk_name,
         return 0;
 err_init:
         kfree(dev->lun_map);
-        kfree(dev);
         return ret;
 }
 EXPORT_SYMBOL(nvm_register);
 
-void nvm_unregister(char *disk_name)
+void nvm_unregister(struct nvm_dev *dev)
 {
-        struct nvm_dev *dev;
-
         down_write(&nvm_lock);
-        dev = nvm_find_nvm_dev(disk_name);
-        if (!dev) {
-                pr_err("nvm: could not find device %s to unregister\n",
-                                                                disk_name);
-                up_write(&nvm_lock);
-                return;
-        }
-
         list_del(&dev->devices);
         up_write(&nvm_lock);
 
         nvm_exit(dev);
-        kfree(dev);
 }
 EXPORT_SYMBOL(nvm_unregister);