lightnvm: introduce ioctl to initialize device

Based on the previous patch, we now introduce an ioctl to initialize the
device using nvm_init_sysblock and create the necessary system blocks.
The user may specify the media manager that they wish to instantiate on
top. Default from user-space will be "gennvm".
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/lightnvm/core.c

@@ -1019,6 +1019,54 @@ static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
 	return __nvm_configure_remove(&remove);
 }
 
+static void nvm_setup_nvm_sb_info(struct nvm_sb_info *info)
+{
+	info->seqnr = 1;
+	info->erase_cnt = 0;
+	info->version = 1;
+}
+
+static long __nvm_ioctl_dev_init(struct nvm_ioctl_dev_init *init)
+{
+	struct nvm_dev *dev;
+	struct nvm_sb_info info;
+
+	down_write(&nvm_lock);
+	dev = nvm_find_nvm_dev(init->dev);
+	up_write(&nvm_lock);
+	if (!dev) {
+		pr_err("nvm: device not found\n");
+		return -EINVAL;
+	}
+
+	nvm_setup_nvm_sb_info(&info);
+
+	strncpy(info.mmtype, init->mmtype, NVM_MMTYPE_LEN);
+	info.fs_ppa.ppa = -1;
+
+	return nvm_init_sysblock(dev, &info);
+}
+
+static long nvm_ioctl_dev_init(struct file *file, void __user *arg)
+{
+	struct nvm_ioctl_dev_init init;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (copy_from_user(&init, arg, sizeof(struct nvm_ioctl_dev_init)))
+		return -EFAULT;
+
+	if (init.flags != 0) {
+		pr_err("nvm: no flags supported\n");
+		return -EINVAL;
+	}
+
+	init.dev[DISK_NAME_LEN - 1] = '\0';
+
+	return __nvm_ioctl_dev_init(&init);
+}
+
 static long nvm_ctl_ioctl(struct file *file, uint cmd, unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
@@ -1032,6 +1080,8 @@ static long nvm_ctl_ioctl(struct file *file, uint cmd, unsigned long arg)
 		return nvm_ioctl_dev_create(file, argp);
 	case NVM_DEV_REMOVE:
 		return nvm_ioctl_dev_remove(file, argp);
+	case NVM_DEV_INIT:
+		return nvm_ioctl_dev_init(file, argp);
 	}
 	return 0;
 }

include/uapi/linux/lightnvm.h

@@ -101,6 +101,12 @@ struct nvm_ioctl_remove {
 	__u32 flags;
 };
 
+struct nvm_ioctl_dev_init {
+	char dev[DISK_NAME_LEN];		/* open-channel SSD device */
+	char mmtype[NVM_MMTYPE_LEN];		/* register to media manager */
+
+	__u32 flags;
+};
 
 /* The ioctl type, 'L', 0x20 - 0x2F documented in ioctl-number.txt */
 enum {
@@ -111,6 +117,9 @@ enum {
 	/* device level cmds */
 	NVM_DEV_CREATE_CMD,
 	NVM_DEV_REMOVE_CMD,
+
+	/* Init a device to support LightNVM media managers */
+	NVM_DEV_INIT_CMD,
 };
 
 #define NVM_IOCTL 'L' /* 0x4c */
@@ -123,6 +132,8 @@ enum {
 						struct nvm_ioctl_create)
 #define NVM_DEV_REMOVE		_IOW(NVM_IOCTL, NVM_DEV_REMOVE_CMD, \
 						struct nvm_ioctl_remove)
+#define NVM_DEV_INIT		_IOW(NVM_IOCTL, NVM_DEV_INIT_CMD, \
+						struct nvm_ioctl_dev_init)
 
 #define NVM_VERSION_MAJOR	1
 #define NVM_VERSION_MINOR	0