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init: do_mounts: use kmalloc() for allocations of temporary buffers

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Several places in init/do_mounts.c allocate temporary buffers for
filesystem names or options using __get_free_page() or alloc_page().

Usage of alloc_page() APIs is not required there and only creates
unnecessary noise with castings or conversion from struct page to void *.

kmalloc() is a better API for these uses and it also provides better
scalability and more debugging possibilities.

Replace use of __get_free_page() and alloc_page() with kmalloc().

While on it, add a check for -ENOMEM condition in mount_root_generic().

Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260520-init-v1-1-aaf2ebac5ad9@kernel.org
Reviewed-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This commit is contained in:
Mike Rapoport (Microsoft) 2026-05-20 11:16:51 +03:00 committed by Christian Brauner
parent 7dc6acb3d5
commit 3fb2d124b6
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 10 additions and 11 deletions
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21
init/do_mounts.c
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@ -143,16 +143,14 @@ static int __init do_mount_root(const char *name, const char *fs,
const int flags, const void *data)
{
struct super_block *s;
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)
data_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!data_page)
return -ENOMEM;
data_page = page_address(p);
strscpy_pad(data_page, data, PAGE_SIZE);
}
@ -170,19 +168,20 @@ static int __init do_mount_root(const char *name, const char *fs,
MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
out:
if (p)
put_page(p);
kfree(data_page);
return ret;
}
void __init mount_root_generic(char *name, char *pretty_name, int flags)
{
struct page *page = alloc_page(GFP_KERNEL);
char *fs_names = page_address(page);
char *fs_names = kmalloc(PAGE_SIZE, GFP_KERNEL);
char *p;
char b[BDEVNAME_SIZE];
int num_fs, i;
if (!fs_names)
panic("VFS: Unable to mount root fs: not enough memory");
scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
if (root_fs_names)
@ -242,7 +241,7 @@ void __init mount_root_generic(char *name, char *pretty_name, int flags)
printk("\n");
panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, b);
out:
put_page(page);
kfree(fs_names);
}
#ifdef CONFIG_ROOT_NFS
@ -343,7 +342,7 @@ static int __init mount_nodev_root(char *root_device_name)
int err = -EINVAL;
int num_fs, i;
fs_names = (void *)__get_free_page(GFP_KERNEL);
fs_names = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!fs_names)
return -EINVAL;
num_fs = split_fs_names(fs_names, PAGE_SIZE);
@ -360,7 +359,7 @@ static int __init mount_nodev_root(char *root_device_name)
break;
}
free_page((unsigned long)fs_names);
kfree(fs_names);
return err;
}