1 files changed, 304 insertions, 372 deletions

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 816014c4627e..defbbf1d55f7 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -1,13 +1,4 @@
-/*
- * Many of the syscalls used in this file expect some of the arguments
- * to be __user pointers not __kernel pointers.  To limit the sparse
- * noise, turn off sparse checking for this file.
- */
-#ifdef __CHECKER__
-#undef __CHECKER__
-#warning "Sparse checking disabled for this file"
-#endif
-
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/ctype.h>
@@ -17,7 +8,6 @@
 #include <linux/root_dev.h>
 #include <linux/security.h>
 #include <linux/delay.h>
-#include <linux/genhd.h>
 #include <linux/mount.h>
 #include <linux/device.h>
 #include <linux/init.h>
@@ -26,17 +16,19 @@
 #include <linux/async.h>
 #include <linux/fs_struct.h>
 #include <linux/slab.h>
+#include <linux/ramfs.h>
+#include <linux/shmem_fs.h>
+#include <linux/ktime.h>
 
 #include <linux/nfs_fs.h>
 #include <linux/nfs_fs_sb.h>
 #include <linux/nfs_mount.h>
+#include <linux/raid/detect.h>
+#include <uapi/linux/mount.h>
 
 #include "do_mounts.h"
 
-int __initdata rd_doload;	/* 1 = load RAM disk, 0 = don't load */
-
 int root_mountflags = MS_RDONLY | MS_SILENT;
-static char * __initdata root_device_name;
 static char __initdata saved_root_name[64];
 static int root_wait;
 
@@ -44,7 +36,7 @@ dev_t ROOT_DEV;
 
 static int __init load_ramdisk(char *str)
 {
-	rd_doload = simple_strtol(str,NULL,0) & 3;
+	pr_warn("ignoring the deprecated load_ramdisk= option\n");
 	return 1;
 }
 __setup("load_ramdisk=", load_ramdisk);
@@ -68,237 +60,48 @@ static int __init readwrite(char *str)
 __setup("ro", readonly);
 __setup("rw", readwrite);
 
-#ifdef CONFIG_BLOCK
-struct uuidcmp {
-	const char *uuid;
-	int len;
-};
-
-/**
- * match_dev_by_uuid - callback for finding a partition using its uuid
- * @dev:	device passed in by the caller
- * @data:	opaque pointer to the desired struct uuidcmp to match
- *
- * Returns 1 if the device matches, and 0 otherwise.
- */
-static int match_dev_by_uuid(struct device *dev, const void *data)
+static int __init root_dev_setup(char *line)
 {
-	const struct uuidcmp *cmp = data;
-	struct hd_struct *part = dev_to_part(dev);
-
-	if (!part->info)
-		goto no_match;
-
-	if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
-		goto no_match;
-
+	strscpy(saved_root_name, line, sizeof(saved_root_name));
 	return 1;
-no_match:
-	return 0;
 }
 
+__setup("root=", root_dev_setup);
 
-/**
- * devt_from_partuuid - looks up the dev_t of a partition by its UUID
- * @uuid:	char array containing ascii UUID
- *
- * The function will return the first partition which contains a matching
- * UUID value in its partition_meta_info struct.  This does not search
- * by filesystem UUIDs.
- *
- * If @uuid is followed by a "/PARTNROFF=%d", then the number will be
- * extracted and used as an offset from the partition identified by the UUID.
- *
- * Returns the matching dev_t on success or 0 on failure.
- */
-static dev_t devt_from_partuuid(const char *uuid_str)
+static int __init rootwait_setup(char *str)
 {
-	dev_t res = 0;
-	struct uuidcmp cmp;
-	struct device *dev = NULL;
-	struct gendisk *disk;
-	struct hd_struct *part;
-	int offset = 0;
-	bool clear_root_wait = false;
-	char *slash;
-
-	cmp.uuid = uuid_str;
-
-	slash = strchr(uuid_str, '/');
-	/* Check for optional partition number offset attributes. */
-	if (slash) {
-		char c = 0;
-		/* Explicitly fail on poor PARTUUID syntax. */
-		if (sscanf(slash + 1,
-			   "PARTNROFF=%d%c", &offset, &c) != 1) {
-			clear_root_wait = true;
-			goto done;
-		}
-		cmp.len = slash - uuid_str;
-	} else {
-		cmp.len = strlen(uuid_str);
-	}
-
-	if (!cmp.len) {
-		clear_root_wait = true;
-		goto done;
-	}
-
-	dev = class_find_device(&block_class, NULL, &cmp,
-				&match_dev_by_uuid);
-	if (!dev)
-		goto done;
-
-	res = dev->devt;
-
-	/* Attempt to find the partition by offset. */
-	if (!offset)
-		goto no_offset;
-
-	res = 0;
-	disk = part_to_disk(dev_to_part(dev));
-	part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
-	if (part) {
-		res = part_devt(part);
-		put_device(part_to_dev(part));
-	}
-
-no_offset:
-	put_device(dev);
-done:
-	if (clear_root_wait) {
-		pr_err("VFS: PARTUUID= is invalid.\n"
-		       "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
-		if (root_wait)
-			pr_err("Disabling rootwait; root= is invalid.\n");
-		root_wait = 0;
-	}
-	return res;
+	if (*str)
+		return 0;
+	root_wait = -1;
+	return 1;
 }
-#endif
 
-/*
- *	Convert a name into device number.  We accept the following variants:
- *
- *	1) device number in hexadecimal	represents itself
- *	2) /dev/nfs represents Root_NFS (0xff)
- *	3) /dev/<disk_name> represents the device number of disk
- *	4) /dev/<disk_name><decimal> represents the device number
- *         of partition - device number of disk plus the partition number
- *	5) /dev/<disk_name>p<decimal> - same as the above, that form is
- *	   used when disk name of partitioned disk ends on a digit.
- *	6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
- *	   unique id of a partition if the partition table provides it.
- *	   The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
- *	   partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
- *	   filled hex representation of the 32-bit "NT disk signature", and PP
- *	   is a zero-filled hex representation of the 1-based partition number.
- *	7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
- *	   a partition with a known unique id.
- *
- *	If name doesn't have fall into the categories above, we return (0,0).
- *	block_class is used to check if something is a disk name. If the disk
- *	name contains slashes, the device name has them replaced with
- *	bangs.
- */
+__setup("rootwait", rootwait_setup);
 
-dev_t name_to_dev_t(char *name)
+static int __init rootwait_timeout_setup(char *str)
 {
-	char s[32];
-	char *p;
-	dev_t res = 0;
-	int part;
+	int sec;
 
-#ifdef CONFIG_BLOCK
-	if (strncmp(name, "PARTUUID=", 9) == 0) {
-		name += 9;
-		res = devt_from_partuuid(name);
-		if (!res)
-			goto fail;
-		goto done;
+	if (kstrtoint(str, 0, &sec) || sec < 0) {
+		pr_warn("ignoring invalid rootwait value\n");
+		goto ignore;
 	}
-#endif
 
-	if (strncmp(name, "/dev/", 5) != 0) {
-		unsigned maj, min;
-
-		if (sscanf(name, "%u:%u", &maj, &min) == 2) {
-			res = MKDEV(maj, min);
-			if (maj != MAJOR(res) || min != MINOR(res))
-				goto fail;
-		} else {
-			res = new_decode_dev(simple_strtoul(name, &p, 16));
-			if (*p)
-				goto fail;
-		}
-		goto done;
+	if (check_mul_overflow(sec, MSEC_PER_SEC, &root_wait)) {
+		pr_warn("ignoring excessive rootwait value\n");
+		goto ignore;
 	}
 
-	name += 5;
-	res = Root_NFS;
-	if (strcmp(name, "nfs") == 0)
-		goto done;
-	res = Root_RAM0;
-	if (strcmp(name, "ram") == 0)
-		goto done;
-
-	if (strlen(name) > 31)
-		goto fail;
-	strcpy(s, name);
-	for (p = s; *p; p++)
-		if (*p == '/')
-			*p = '!';
-	res = blk_lookup_devt(s, 0);
-	if (res)
-		goto done;
-
-	/*
-	 * try non-existent, but valid partition, which may only exist
-	 * after revalidating the disk, like partitioned md devices
-	 */
-	while (p > s && isdigit(p[-1]))
-		p--;
-	if (p == s || !*p || *p == '0')
-		goto fail;
-
-	/* try disk name without <part number> */
-	part = simple_strtoul(p, NULL, 10);
-	*p = '\0';
-	res = blk_lookup_devt(s, part);
-	if (res)
-		goto done;
-
-	/* try disk name without p<part number> */
-	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
-		goto fail;
-	p[-1] = '\0';
-	res = blk_lookup_devt(s, part);
-	if (res)
-		goto done;
-
-fail:
-	return 0;
-done:
-	return res;
-}
-
-static int __init root_dev_setup(char *line)
-{
-	strlcpy(saved_root_name, line, sizeof(saved_root_name));
 	return 1;
-}
 
-__setup("root=", root_dev_setup);
+ignore:
+	/* Fallback to indefinite wait */
+	root_wait = -1;
 
-static int __init rootwait_setup(char *str)
-{
-	if (*str)
-		return 0;
-	root_wait = 1;
 	return 1;
 }
 
-__setup("rootwait", rootwait_setup);
+__setup("rootwait=", rootwait_timeout_setup);
 
 static char * __initdata root_mount_data;
 static int __init root_data_setup(char *str)
@@ -317,7 +120,8 @@ static int __init fs_names_setup(char *str)
 static unsigned int __initdata root_delay;
 static int __init root_delay_setup(char *str)
 {
-	root_delay = simple_strtoul(str, NULL, 0);
+	if (kstrtouint(str, 0, &root_delay))
+		return 0;
 	return 1;
 }
 
@@ -325,74 +129,88 @@ __setup("rootflags=", root_data_setup);
 __setup("rootfstype=", fs_names_setup);
 __setup("rootdelay=", root_delay_setup);
 
-static void __init get_fs_names(char *page)
+/* This can return zero length strings. Caller should check */
+static int __init split_fs_names(char *page, size_t size)
 {
-	char *s = page;
-
-	if (root_fs_names) {
-		strcpy(page, root_fs_names);
-		while (*s++) {
-			if (s[-1] == ',')
-				s[-1] = '\0';
-		}
-	} else {
-		int len = get_filesystem_list(page);
-		char *p, *next;
-
-		page[len] = '\0';
-		for (p = page-1; p; p = next) {
-			next = strchr(++p, '\n');
-			if (*p++ != '\t')
-				continue;
-			while ((*s++ = *p++) != '\n')
-				;
-			s[-1] = '\0';
+	int count = 1;
+	char *p = page;
+
+	strscpy(p, root_fs_names, size);
+	while (*p++) {
+		if (p[-1] == ',') {
+			p[-1] = '\0';
+			count++;
 		}
 	}
-	*s = '\0';
+
+	return count;
 }
 
-static int __init do_mount_root(char *name, char *fs, int flags, void *data)
+static int __init do_mount_root(const char *name, const char *fs,
+				 const int flags, const void *data)
 {
 	struct super_block *s;
-	int err = sys_mount(name, "/root", fs, flags, data);
-	if (err)
-		return err;
+	struct page *p = NULL;
+	char *data_page = NULL;
+	int ret;
+
+	if (data) {
+		/* init_mount() requires a full page as fifth argument */
+		p = alloc_page(GFP_KERNEL);
+		if (!p)
+			return -ENOMEM;
+		data_page = page_address(p);
+		strscpy_pad(data_page, data, PAGE_SIZE);
+	}
 
-	sys_chdir("/root");
+	ret = init_mount(name, "/root", fs, flags, data_page);
+	if (ret)
+		goto out;
+
+	init_chdir("/root");
 	s = current->fs->pwd.dentry->d_sb;
 	ROOT_DEV = s->s_dev;
 	printk(KERN_INFO
 	       "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
 	       s->s_type->name,
-	       s->s_flags & MS_RDONLY ?  " readonly" : "",
+	       sb_rdonly(s) ? " readonly" : "",
 	       MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
-	return 0;
+
+out:
+	if (p)
+		put_page(p);
+	return ret;
 }
 
-void __init mount_block_root(char *name, int flags)
+void __init mount_root_generic(char *name, char *pretty_name, int flags)
 {
-	struct page *page = alloc_page(GFP_KERNEL |
-					__GFP_NOTRACK_FALSE_POSITIVE);
+	struct page *page = alloc_page(GFP_KERNEL);
 	char *fs_names = page_address(page);
 	char *p;
-#ifdef CONFIG_BLOCK
 	char b[BDEVNAME_SIZE];
-#else
-	const char *b = name;
-#endif
-
-	get_fs_names(fs_names);
+	int num_fs, i;
+
+	scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
+		  MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
+	if (root_fs_names)
+		num_fs = split_fs_names(fs_names, PAGE_SIZE);
+	else
+		num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
 retry:
-	for (p = fs_names; *p; p += strlen(p)+1) {
-		int err = do_mount_root(name, p, flags, root_mount_data);
+	for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
+		int err;
+
+		if (!*p)
+			continue;
+		err = do_mount_root(name, p, flags, root_mount_data);
 		switch (err) {
 			case 0:
 				goto out;
 			case -EACCES:
-				flags |= MS_RDONLY;
-				goto retry;
 			case -EINVAL:
+#ifdef CONFIG_BLOCK
+				init_flush_fput();
+#endif
 				continue;
 		}
 	        /*
@@ -400,31 +218,36 @@ retry:
 		 * and bad superblock on root device.
 		 * and give them a list of the available devices
 		 */
-#ifdef CONFIG_BLOCK
-		__bdevname(ROOT_DEV, b);
-#endif
 		printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
-				root_device_name, b, err);
+				pretty_name, b, err);
 		printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
-
 		printk_all_partitions();
-#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
-		printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
-		       "explicit textual name for \"root=\" boot option.\n");
-#endif
+
+		if (root_fs_names)
+			num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
+		if (!num_fs)
+			pr_err("Can't find any bdev filesystem to be used for mount!\n");
+		else {
+			pr_err("List of all bdev filesystems:\n");
+			for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
+				pr_err(" %s", p);
+			pr_err("\n");
+		}
+
 		panic("VFS: Unable to mount root fs on %s", b);
 	}
+	if (!(flags & SB_RDONLY)) {
+		flags |= SB_RDONLY;
+		goto retry;
+	}
 
 	printk("List of all partitions:\n");
 	printk_all_partitions();
 	printk("No filesystem could mount root, tried: ");
-	for (p = fs_names; *p; p += strlen(p)+1)
+	for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
 		printk(" %s", p);
 	printk("\n");
-#ifdef CONFIG_BLOCK
-	__bdevname(ROOT_DEV, b);
-#endif
-	panic("VFS: Unable to mount root fs on %s", b);
+	panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, b);
 out:
 	put_page(page);
 }
@@ -435,15 +258,14 @@ out:
 #define NFSROOT_TIMEOUT_MAX	30
 #define NFSROOT_RETRY_MAX	5
 
-static int __init mount_nfs_root(void)
+static void __init mount_nfs_root(void)
 {
 	char *root_dev, *root_data;
 	unsigned int timeout;
-	int try, err;
+	int try;
 
-	err = nfs_root_data(&root_dev, &root_data);
-	if (err != 0)
-		return 0;
+	if (nfs_root_data(&root_dev, &root_data))
+		goto fail;
 
 	/*
 	 * The server or network may not be ready, so try several
@@ -452,10 +274,8 @@ static int __init mount_nfs_root(void)
 	 */
 	timeout = NFSROOT_TIMEOUT_MIN;
 	for (try = 1; ; try++) {
-		err = do_mount_root(root_dev, "nfs",
-					root_mountflags, root_data);
-		if (err == 0)
-			return 1;
+		if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data))
+			return;
 		if (try > NFSROOT_RETRY_MAX)
 			break;
 
@@ -465,67 +285,178 @@ static int __init mount_nfs_root(void)
 		if (timeout > NFSROOT_TIMEOUT_MAX)
 			timeout = NFSROOT_TIMEOUT_MAX;
 	}
-	return 0;
+fail:
+	pr_err("VFS: Unable to mount root fs via NFS.\n");
 }
-#endif
+#else
+static inline void mount_nfs_root(void)
+{
+}
+#endif /* CONFIG_ROOT_NFS */
 
-#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
-void __init change_floppy(char *fmt, ...)
+#ifdef CONFIG_CIFS_ROOT
+
+#define CIFSROOT_TIMEOUT_MIN	5
+#define CIFSROOT_TIMEOUT_MAX	30
+#define CIFSROOT_RETRY_MAX	5
+
+static void __init mount_cifs_root(void)
 {
-	struct termios termios;
-	char buf[80];
-	char c;
-	int fd;
-	va_list args;
-	va_start(args, fmt);
-	vsprintf(buf, fmt, args);
-	va_end(args);
-	fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
-	if (fd >= 0) {
-		sys_ioctl(fd, FDEJECT, 0);
-		sys_close(fd);
-	}
-	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
-	fd = sys_open("/dev/console", O_RDWR, 0);
-	if (fd >= 0) {
-		sys_ioctl(fd, TCGETS, (long)&termios);
-		termios.c_lflag &= ~ICANON;
-		sys_ioctl(fd, TCSETSF, (long)&termios);
-		sys_read(fd, &c, 1);
-		termios.c_lflag |= ICANON;
-		sys_ioctl(fd, TCSETSF, (long)&termios);
-		sys_close(fd);
+	char *root_dev, *root_data;
+	unsigned int timeout;
+	int try;
+
+	if (cifs_root_data(&root_dev, &root_data))
+		goto fail;
+
+	timeout = CIFSROOT_TIMEOUT_MIN;
+	for (try = 1; ; try++) {
+		if (!do_mount_root(root_dev, "cifs", root_mountflags,
+				   root_data))
+			return;
+		if (try > CIFSROOT_RETRY_MAX)
+			break;
+
+		ssleep(timeout);
+		timeout <<= 1;
+		if (timeout > CIFSROOT_TIMEOUT_MAX)
+			timeout = CIFSROOT_TIMEOUT_MAX;
 	}
+fail:
+	pr_err("VFS: Unable to mount root fs via SMB.\n");
 }
-#endif
+#else
+static inline void mount_cifs_root(void)
+{
+}
+#endif /* CONFIG_CIFS_ROOT */
 
-void __init mount_root(void)
+static bool __init fs_is_nodev(char *fstype)
 {
-#ifdef CONFIG_ROOT_NFS
-	if (ROOT_DEV == Root_NFS) {
-		if (mount_nfs_root())
-			return;
+	struct file_system_type *fs = get_fs_type(fstype);
+	bool ret = false;
 
-		printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
-		ROOT_DEV = Root_FD0;
+	if (fs) {
+		ret = !(fs->fs_flags & FS_REQUIRES_DEV);
+		put_filesystem(fs);
 	}
-#endif
-#ifdef CONFIG_BLK_DEV_FD
-	if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
-		/* rd_doload is 2 for a dual initrd/ramload setup */
-		if (rd_doload==2) {
-			if (rd_load_disk(1)) {
-				ROOT_DEV = Root_RAM1;
-				root_device_name = NULL;
-			}
-		} else
-			change_floppy("root floppy");
+
+	return ret;
+}
+
+static int __init mount_nodev_root(char *root_device_name)
+{
+	char *fs_names, *fstype;
+	int err = -EINVAL;
+	int num_fs, i;
+
+	fs_names = (void *)__get_free_page(GFP_KERNEL);
+	if (!fs_names)
+		return -EINVAL;
+	num_fs = split_fs_names(fs_names, PAGE_SIZE);
+
+	for (i = 0, fstype = fs_names; i < num_fs;
+	     i++, fstype += strlen(fstype) + 1) {
+		if (!*fstype)
+			continue;
+		if (!fs_is_nodev(fstype))
+			continue;
+		err = do_mount_root(root_device_name, fstype, root_mountflags,
+				    root_mount_data);
+		if (!err)
+			break;
 	}
-#endif
+
+	free_page((unsigned long)fs_names);
+	return err;
+}
+
 #ifdef CONFIG_BLOCK
-	create_dev("/dev/root", ROOT_DEV);
-	mount_block_root("/dev/root", root_mountflags);
-#endif
+static void __init mount_block_root(char *root_device_name)
+{
+	int err = create_dev("/dev/root", ROOT_DEV);
+
+	if (err < 0)
+		pr_emerg("Failed to create /dev/root: %d\n", err);
+	mount_root_generic("/dev/root", root_device_name, root_mountflags);
+}
+#else
+static inline void mount_block_root(char *root_device_name)
+{
+}
+#endif /* CONFIG_BLOCK */
+
+void __init mount_root(char *root_device_name)
+{
+	switch (ROOT_DEV) {
+	case Root_NFS:
+		mount_nfs_root();
+		break;
+	case Root_CIFS:
+		mount_cifs_root();
+		break;
+	case Root_Generic:
+		mount_root_generic(root_device_name, root_device_name,
+				   root_mountflags);
+		break;
+	case 0:
+		if (root_device_name && root_fs_names &&
+		    mount_nodev_root(root_device_name) == 0)
+			break;
+		fallthrough;
+	default:
+		mount_block_root(root_device_name);
+		break;
+	}
+}
+
+/* wait for any asynchronous scanning to complete */
+static void __init wait_for_root(char *root_device_name)
+{
+	ktime_t end;
+
+	if (ROOT_DEV != 0)
+		return;
+
+	pr_info("Waiting for root device %s...\n", root_device_name);
+
+	end = ktime_add_ms(ktime_get_raw(), root_wait);
+
+	while (!driver_probe_done() ||
+	       early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) {
+		msleep(5);
+		if (root_wait > 0 && ktime_after(ktime_get_raw(), end))
+			break;
+	}
+
+	async_synchronize_full();
+
+}
+
+static dev_t __init parse_root_device(char *root_device_name)
+{
+	int error;
+	dev_t dev;
+
+	if (!strncmp(root_device_name, "mtd", 3) ||
+	    !strncmp(root_device_name, "ubi", 3))
+		return Root_Generic;
+	if (strcmp(root_device_name, "/dev/nfs") == 0)
+		return Root_NFS;
+	if (strcmp(root_device_name, "/dev/cifs") == 0)
+		return Root_CIFS;
+	if (strcmp(root_device_name, "/dev/ram") == 0)
+		return Root_RAM0;
+
+	error = early_lookup_bdev(root_device_name, &dev);
+	if (error) {
+		if (error == -EINVAL && root_wait) {
+			pr_err("Disabling rootwait; root= is invalid.\n");
+			root_wait = 0;
+		}
+		return 0;
+	}
+	return dev;
 }
 
 /*
@@ -533,8 +464,6 @@ void __init mount_root(void)
  */
 void __init prepare_namespace(void)
 {
-	int is_floppy;
-
 	if (root_delay) {
 		printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
 		       root_delay);
@@ -552,39 +481,42 @@ void __init prepare_namespace(void)
 
 	md_run_setup();
 
-	if (saved_root_name[0]) {
-		root_device_name = saved_root_name;
-		if (!strncmp(root_device_name, "mtd", 3) ||
-		    !strncmp(root_device_name, "ubi", 3)) {
-			mount_block_root(root_device_name, root_mountflags);
-			goto out;
-		}
-		ROOT_DEV = name_to_dev_t(root_device_name);
-		if (strncmp(root_device_name, "/dev/", 5) == 0)
-			root_device_name += 5;
-	}
+	if (saved_root_name[0])
+		ROOT_DEV = parse_root_device(saved_root_name);
 
-	if (initrd_load())
+	if (initrd_load(saved_root_name))
 		goto out;
 
-	/* wait for any asynchronous scanning to complete */
-	if ((ROOT_DEV == 0) && root_wait) {
-		printk(KERN_INFO "Waiting for root device %s...\n",
-			saved_root_name);
-		while (driver_probe_done() != 0 ||
-			(ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
-			msleep(100);
-		async_synchronize_full();
-	}
+	if (root_wait)
+		wait_for_root(saved_root_name);
+	mount_root(saved_root_name);
+out:
+	devtmpfs_mount();
+	init_mount(".", "/", NULL, MS_MOVE, NULL);
+	init_chroot(".");
+}
+
+static bool is_tmpfs;
+static int rootfs_init_fs_context(struct fs_context *fc)
+{
+	if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
+		return shmem_init_fs_context(fc);
 
-	is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
+	return ramfs_init_fs_context(fc);
+}
 
-	if (is_floppy && rd_doload && rd_load_disk(0))
-		ROOT_DEV = Root_RAM0;
+struct file_system_type rootfs_fs_type = {
+	.name		= "rootfs",
+	.init_fs_context = rootfs_init_fs_context,
+	.kill_sb	= kill_anon_super,
+};
 
-	mount_root();
-out:
-	devtmpfs_mount("dev");
-	sys_mount(".", "/", NULL, MS_MOVE, NULL);
-	sys_chroot(".");
+void __init init_rootfs(void)
+{
+	if (IS_ENABLED(CONFIG_TMPFS)) {
+		if (!saved_root_name[0] && !root_fs_names)
+			is_tmpfs = true;
+		else if (root_fs_names && !!strstr(root_fs_names, "tmpfs"))
+			is_tmpfs = true;
+	}
 }