[PATCH 2/4] fs: split rootargs into root and options
Ahmad Fatoum
a.fatoum at pengutronix.de
Wed Nov 26 02:31:08 PST 2025
Hi,
On 11/26/25 7:42 AM, Fabian Pflug wrote:
> The rootargs argument (root=/dev/etc rootwait) can be split into the
> root and options parts, which makes it easier to manipulate them both
> independently. This changes tries to be as backward compatible as
> possible and does not change the behaviour of the get functions, but
> introduces new ones to get both items seperatly.
>
> Signed-off-by: Fabian Pflug <f.pflug at pengutronix.de>
> ---
> common/block.c | 42 ++++++++++++++++++-------------
> fs/9p/vfs_super.c | 6 ++---
> fs/fs.c | 57 +++++++++++++++++++++++++++++++-----------
> fs/nfs.c | 4 +--
> fs/squashfs/squashfs.c | 13 ++++++----
> fs/ubifs/ubifs.c | 12 +++++----
> include/block.h | 6 +++++
> include/fs.h | 6 +++--
> 8 files changed, 98 insertions(+), 48 deletions(-)
>
> diff --git a/common/block.c b/common/block.c
> index ce3aee49b4..35e90dc4a6 100644
> --- a/common/block.c
> +++ b/common/block.c
> @@ -584,34 +584,42 @@ const char *blk_type_str(enum blk_type type)
> }
> }
>
> -char *cdev_get_linux_rootarg(const struct cdev *partcdev)
> -{
> +void cdev_get_linux_root_and_opts(const struct cdev *partcdev, char** root, char** rootopts) {
> +
> const struct cdev *cdevm;
> struct block_device *blk;
> - char *rootarg = NULL;
> - char* root = NULL;
> +
> + *root = NULL;
> + *rootopts = NULL;
>
> if (!partcdev)
> - return NULL;
> + return;
>
> cdevm = partcdev->master ?: partcdev;
> blk = cdev_get_block_device(cdevm);
> if (!blk)
> - return NULL;
> + return;
>
> - if (blk->ops->get_root) {
> - root = blk->ops->get_root(blk, partcdev);
> - if(root) {
> - rootarg = basprintf("root=%s", root);
> - free(root);
> - }
> - }
> - if (!rootarg && partcdev->partuuid[0] != 0)
> - rootarg = basprintf("root=PARTUUID=%s", partcdev->partuuid);
> + if (blk->ops->get_root)
> + *root = blk->ops->get_root(blk, partcdev);
> + if (!*root && partcdev->partuuid[0] != 0)
> + *root = basprintf("PARTUUID=%s", partcdev->partuuid);
>
> if (IS_ENABLED(CONFIG_ROOTWAIT_BOOTARG) && blk->rootwait)
> - rootarg = linux_bootargs_append_rootwait(rootarg);
> + *rootopts = xasprintf("rootwait=%d", linux_rootwait_secs);
>
> - return rootarg;
> + return;
> }
>
> +char *cdev_get_linux_rootarg(const struct cdev *partcdev)
> +{
> + char* root;
> + char* rootopts;
> +
> + cdev_get_linux_root_and_opts(partcdev, &root, &rootopts);
> + if(!root)
> + return NULL;
> + if(rootopts)
> + return xasprintf("root=%s %s", root, rootopts);
> + return xasprintf("root=%s", root);
> +}
> diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
> index 6a451d9ef5..efc9a9193d 100644
> --- a/fs/9p/vfs_super.c
> +++ b/fs/9p/vfs_super.c
> @@ -70,11 +70,11 @@ static void v9fs_set_rootarg(struct v9fs_session_info *v9ses,
> trans = v9ses->clnt->trans_mod->name;
> path = v9ses->aname;
>
> - str = basprintf("root=%s rootfstype=9p rootflags=trans=%s,msize=%d,"
> + str = basprintf("rootfstype=9p rootflags=trans=%s,msize=%d,"
> "cache=loose,uname=%s,dfltuid=0,dfltgid=0,aname=%s",
> - tag, trans, v9ses->clnt->msize, tag, path);
> + trans, v9ses->clnt->msize, tag, path);
>
> - fsdev_set_linux_rootarg(fsdev, str);
> + fsdev_set_linux_root_options(fsdev, tag, str);
>
> free(str);
> }
> diff --git a/fs/fs.c b/fs/fs.c
> index 528299e039..c4f805d308 100644
> --- a/fs/fs.c
> +++ b/fs/fs.c
> @@ -1226,12 +1226,26 @@ void mount_all(void)
> }
> }
>
> -void fsdev_set_linux_rootarg(struct fs_device *fsdev, const char *str)
> +void fsdev_set_linux_root_options(struct fs_device *fsdev, const char *root, const char *rootopts)
> {
> - fsdev->linux_rootarg = xstrdup(str);
> + fsdev->linux_root = xstrdup(root);
> + fsdev->linux_rootopts = xstrdup(rootopts);
>
> - dev_add_param_fixed(&fsdev->dev, "linux.bootargs",
> - "%s", fsdev->linux_rootarg);
> + dev_add_param_fixed(&fsdev->dev, "linux.bootargs.root",
> + "%s", fsdev->linux_root);
> + dev_add_param_fixed(&fsdev->dev, "linux.bootargs.rootopts",
> + "%s", fsdev->linux_rootopts);
Please add an entry to
Documentation/migration-guides/migration-master.rst documenting that
this variable has been replaced for file system devices by
"root={linux.bootargs.root} {linux.bootargs.rootopts}".
Thanks,
Ahmad
> +}
> +
> +void fsdev_get_linux_root_options(struct fs_device *fsdev, char **root, char **rootopts)
> +{
> + if(fsdev) {
> + *root = dev_get_param(&fsdev->dev, "linux.bootargs.root");
> + *rootopts = dev_get_param(&fsdev->dev, "linux.bootargs.rootopts");
> + } else {
> + *root = NULL;
> + *rootopts = NULL;
> + }
> }
>
> /**
> @@ -1245,17 +1259,27 @@ void fsdev_set_linux_rootarg(struct fs_device *fsdev, const char *str)
> char *path_get_linux_rootarg(const char *path)
> {
> struct fs_device *fsdev;
> - const char *str;
> + char *root;
> + char *rootopts;
> + char *rootarg;
>
> fsdev = get_fsdevice_by_path(AT_FDCWD, path);
> if (!fsdev)
> return ERR_PTR(-EINVAL);
>
> - str = dev_get_param(&fsdev->dev, "linux.bootargs");
> - if (!str)
> - return ERR_PTR(-ENOSYS);
> + fsdev_get_linux_root_options(fsdev, &root, &rootopts);
>
> - return xstrdup(str);
> + if(!root)
> + return ERR_PTR(-EINVAL);
> +
> + if(rootopts) {
> + rootarg = xasprintf("root=%s %s", root, rootopts);
> + free(rootopts);
> + } else {
> + rootarg = xasprintf("root=%s", root);
> + }
> + free(root);
> + return rootarg;
> }
>
> /**
> @@ -3249,12 +3273,17 @@ int mount(const char *device, const char *fsname, const char *pathname,
>
> fsdev->vfsmount.mnt_root = fsdev->sb.s_root;
>
> - if (!fsdev->linux_rootarg) {
> - char *str;
> + if (!fsdev->linux_root) {
> + char *root;
> + char *rootopts;
>
> - str = cdev_get_linux_rootarg(fsdev->cdev);
> - if (str)
> - fsdev_set_linux_rootarg(fsdev, str);
> + cdev_get_linux_root_and_opts(fsdev->cdev, &root, &rootopts);
> + if (root) {
> + fsdev_set_linux_root_options(fsdev, root, rootopts);
> + free(root);
> + if(rootopts)
> + free(rootopts);
> + }
> }
>
> path_put(&path);
> diff --git a/fs/nfs.c b/fs/nfs.c
> index 5c2476cd88..0b40c56ff3 100644
> --- a/fs/nfs.c
> +++ b/fs/nfs.c
> @@ -1558,7 +1558,7 @@ static void nfs_set_rootarg(struct nfs_priv *npriv, struct fs_device *fsdev)
> char *str, *tmp;
> const char *bootargs;
>
> - str = basprintf("root=/dev/nfs nfsroot=%pI4:%s%s%s", &npriv->server, npriv->path,
> + str = basprintf("nfsroot=%pI4:%s%s%s", &npriv->server, npriv->path,
> rootnfsopts[0] ? "," : "", rootnfsopts);
>
> /* forward specific mount options on demand */
> @@ -1584,7 +1584,7 @@ static void nfs_set_rootarg(struct nfs_priv *npriv, struct fs_device *fsdev)
> if (IS_ENABLED(CONFIG_ROOTWAIT_BOOTARG))
> str = linux_bootargs_append_rootwait(str);
>
> - fsdev_set_linux_rootarg(fsdev, str);
> + fsdev_set_linux_root_options(fsdev, "/dev/nfs", str);
>
> free(str);
> }
> diff --git a/fs/squashfs/squashfs.c b/fs/squashfs/squashfs.c
> index e30372627a..365aa1f219 100644
> --- a/fs/squashfs/squashfs.c
> +++ b/fs/squashfs/squashfs.c
> @@ -46,7 +46,8 @@ static void squashfs_set_rootarg(struct fs_device *fsdev)
> struct ubi_volume_info vi = {};
> struct ubi_device_info di = {};
> struct mtd_info *mtd;
> - char *str;
> + char *root;
> + char *rootopts;
>
> if (!IS_ENABLED(CONFIG_MTD_UBI))
> return;
> @@ -60,12 +61,14 @@ static void squashfs_set_rootarg(struct fs_device *fsdev)
> ubi_get_device_info(vi.ubi_num, &di);
> mtd = di.mtd;
>
> - str = basprintf("root=/dev/ubiblock%d_%d ubi.mtd=%s ubi.block=%d,%d rootfstype=squashfs",
> - vi.ubi_num, vi.vol_id, mtd->cdev.partname, vi.ubi_num, vi.vol_id);
> + root = basprintf("/dev/ubiblock%d_%d", vi.ubi_num, vi.vol_id);
> + rootopts = basprintf("ubi.mtd=%s ubi.block=%d,%d rootfstype=squashfs",
> + mtd->cdev.partname, vi.ubi_num, vi.vol_id);
>
> - fsdev_set_linux_rootarg(fsdev, str);
> + fsdev_set_linux_root_options(fsdev, root, rootopts);
>
> - free(str);
> + free(root);
> + free(rootopts);
> }
>
> static struct inode *squashfs_alloc_inode(struct super_block *sb)
> diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
> index 37986acbb2..9cc35fa273 100644
> --- a/fs/ubifs/ubifs.c
> +++ b/fs/ubifs/ubifs.c
> @@ -435,19 +435,21 @@ static void ubifs_set_rootarg(struct ubifs_priv *priv,
> struct ubi_volume_info vi = {};
> struct ubi_device_info di = {};
> struct mtd_info *mtd;
> - char *str;
> + char *root;
> + char *rootopts;
>
> ubi_get_volume_info(priv->ubi, &vi);
> ubi_get_device_info(vi.ubi_num, &di);
>
> mtd = di.mtd;
>
> - str = basprintf("root=ubi0:%s ubi.mtd=%s rootfstype=ubifs",
> - vi.name, mtd->cdev.partname);
> + root = basprintf("ubi0:%s", vi.name);
> + rootopts = basprintf("ubi.mtd=%s rootfstype=ubifs", mtd->cdev.partname);
>
> - fsdev_set_linux_rootarg(fsdev, str);
> + fsdev_set_linux_root_options(fsdev, root, rootopts);
>
> - free(str);
> + free(root);
> + free(rootopts);
> }
>
> static int ubifs_probe(struct device *dev)
> diff --git a/include/block.h b/include/block.h
> index b277f590e4..ddab8bfe60 100644
> --- a/include/block.h
> +++ b/include/block.h
> @@ -85,6 +85,7 @@ static inline int block_flush(struct block_device *blk)
> #ifdef CONFIG_BLOCK
> unsigned file_list_add_blockdevs(struct file_list *files);
> char *cdev_get_linux_rootarg(const struct cdev *partcdev);
> +void cdev_get_linux_root_and_opts(const struct cdev *partcdev, char** root, char** rootopts);
> #else
> static inline unsigned file_list_add_blockdevs(struct file_list *files)
> {
> @@ -94,6 +95,11 @@ static inline char *cdev_get_linux_rootarg(const struct cdev *partcdev)
> {
> return NULL;
> }
> +static inline void cdev_get_linux_root_and_opts(const struct cdev *partcdev, char** root, char** rootopts)
> +{
> + root = NULL;
> + rootopts = NULL;
> +}
> #endif
>
> static inline bool cdev_is_block_device(const struct cdev *cdev)
> diff --git a/include/fs.h b/include/fs.h
> index 98c482bbf2..c50437d609 100644
> --- a/include/fs.h
> +++ b/include/fs.h
> @@ -90,7 +90,8 @@ struct fs_device {
> char *path;
> struct list_head list;
> char *options;
> - char *linux_rootarg;
> + char *linux_root;
> + char *linux_rootopts;
>
> struct super_block sb;
>
> @@ -159,7 +160,8 @@ const char *cdev_mount_default(struct cdev *cdev, const char *fsoptions);
> const char *cdev_mount(struct cdev *cdev);
> void mount_all(void);
>
> -void fsdev_set_linux_rootarg(struct fs_device *fsdev, const char *str);
> +void fsdev_set_linux_root_options(struct fs_device *fsdev, const char *root, const char* rootopts);
> +void fsdev_get_linux_root_options(struct fs_device *fsdev, char **root, char **rootopts);
> char *path_get_linux_rootarg(const char *path);
>
> static inline const char *devpath_to_name(const char *devpath)
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
More information about the barebox
mailing list