lightnvm: use system block for mm initialization

Use system block information to register the appropriate media manager.
This enables the LightNVM subsystem to instantiate a media manager
selected by the user, instead of relying on automatic detection by each
media manager loaded in the kernel.

A device must now be initialized before it can proceed to initialize its
media manager. Upon initialization, the configured media manager is
automatically initialized as well.

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

2 files changed, 26 insertions, 2 deletions

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index ee08fac6f327..9e5712dda062 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -106,6 +106,9 @@ struct nvmm_type *nvm_init_mgr(struct nvm_dev *dev)
         lockdep_assert_held(&nvm_lock);
 
         list_for_each_entry(mt, &nvm_mgrs, list) {
+                if (strncmp(dev->sb.mmtype, mt->name, NVM_MMTYPE_LEN))
+                        continue;
+
                 ret = mt->register_mgr(dev);
                 if (ret < 0) {
                         pr_err("nvm: media mgr failed to init (%d) on dev %s\n",
@@ -569,9 +572,16 @@ int nvm_register(struct request_queue *q, char *disk_name,
                 }
         }
 
+        ret = nvm_get_sysblock(dev, &dev->sb);
+        if (!ret)
+                pr_err("nvm: device not initialized.\n");
+        else if (ret < 0)
+                pr_err("nvm: err (%d) on device initialization\n", ret);
+
         /* register device with a supported media manager */
         down_write(&nvm_lock);
-        dev->mt = nvm_init_mgr(dev);
+        if (ret > 0)
+                dev->mt = nvm_init_mgr(dev);
         list_add(&dev->devices, &nvm_devices);
         up_write(&nvm_lock);
 
@@ -1030,6 +1040,7 @@ static long __nvm_ioctl_dev_init(struct nvm_ioctl_dev_init *init)
 {
         struct nvm_dev *dev;
         struct nvm_sb_info info;
+        int ret;
 
         down_write(&nvm_lock);
         dev = nvm_find_nvm_dev(init->dev);
@@ -1044,7 +1055,17 @@ static long __nvm_ioctl_dev_init(struct nvm_ioctl_dev_init *init)
         strncpy(info.mmtype, init->mmtype, NVM_MMTYPE_LEN);
         info.fs_ppa.ppa = -1;
 
-        return nvm_init_sysblock(dev, &info);
+        ret = nvm_init_sysblock(dev, &info);
+        if (ret)
+                return ret;
+
+        memcpy(&dev->sb, &info, sizeof(struct nvm_sb_info));
+
+        down_write(&nvm_lock);
+        dev->mt = nvm_init_mgr(dev);
+        up_write(&nvm_lock);
+
+        return 0;
 }
 
 static long nvm_ioctl_dev_init(struct file *file, void __user *arg)
diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
index 7ad22d3f0d2e..02f36bdf216e 100644
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -301,6 +301,9 @@ struct nvm_dev {
         struct nvmm_type *mt;
         void *mp;
 
+        /* System blocks */
+        struct nvm_sb_info sb;
+
         /* Device information */
         int nr_chnls;
         int nr_planes;