From: Julian Stecklina <julian.stecklina@xxxxxxxxxxxxxxxxxxxxx>
Port cramfs to the new initrd_fs_detect API. There are no functional
changes.
Signed-off-by: Julian Stecklina <julian.stecklina@xxxxxxxxxxxxxxxxxxxxx>
---
fs/cramfs/Makefile | 5 +++++
fs/cramfs/initrd.c | 41 +++++++++++++++++++++++++++++++++++++++++
init/do_mounts_rd.c | 28 ++--------------------------
3 files changed, 48 insertions(+), 26 deletions(-)
diff --git a/fs/cramfs/Makefile b/fs/cramfs/Makefile
index 8c3ed298241924b0312fb489b1fb54d274d25c22..d10e2b72aae06bf9ac42690e3967cfd90ac34d4f 100644
--- a/fs/cramfs/Makefile
+++ b/fs/cramfs/Makefile
@@ -6,3 +6,8 @@
obj-$(CONFIG_CRAMFS) += cramfs.o
cramfs-objs := inode.o uncompress.o
+
+# If we are built-in, we provide support for cramfs on initrds.
+ifeq ($(CONFIG_CRAMFS),y)
+cramfs-objs += initrd.o
+endif
diff --git a/fs/cramfs/initrd.c b/fs/cramfs/initrd.c
new file mode 100644
index 0000000000000000000000000000000000000000..c16df09c118226e6350b9f5877863ef31322ab7b
--- /dev/null
+++ b/fs/cramfs/initrd.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/fs.h>
+#include <linux/initrd.h>
+#include <uapi/linux/cramfs_fs.h>
+
+/*
+ * The filesystem start maybe padded by this many bytes to make space
+ * for boot loaders.
+ */
+#define CRAMFS_PAD_OFFSET 512
+
+static size_t __init check_cramfs_sb(struct cramfs_super *cramfsb)
+{
+ if (cramfsb->magic != CRAMFS_MAGIC)
+ return 0;
+
+ return cramfsb->size;
+}
+
+static size_t __init detect_cramfs(void *block_data)
+{
+ size_t fssize;
+
+ BUILD_BUG_ON(sizeof(struct cramfs_super) + CRAMFS_PAD_OFFSET
+ > BLOCK_SIZE);
+
+ fssize = check_cramfs_sb((struct cramfs_super *)block_data);
+ if (fssize)
+ return fssize;
+
+ /*
+ * The header padding doesn't influence the total length of
+ * the filesystem.
+ */
+ block_data = (char *)block_data + CRAMFS_PAD_OFFSET;
+ fssize = check_cramfs_sb((struct cramfs_super *)block_data);
+ return fssize;
+}
+
+initrd_fs_detect(detect_cramfs, 0);
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index f7e5d4ccf029b2707bc8524ecdbe200c8b305b00..cdc39baaf3a1a65daad5fe6571a82faf3fc95b62 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -3,7 +3,7 @@
#include <linux/fs.h>
#include <linux/ext2_fs.h>
#include <linux/romfs_fs.h>
-#include <uapi/linux/cramfs_fs.h>
+
#include <linux/initrd.h>
#include <linux/string.h>
#include <linux/slab.h>
@@ -43,7 +43,6 @@ static int __init crd_load(decompress_fn deco);
* We currently check for the following magic numbers:
* ext2
* romfs
- * cramfs
* squashfs
* gzip
* bzip2
@@ -58,7 +57,7 @@ identify_ramdisk_image(struct file *file, loff_t pos,
{
const int size = BLOCK_SIZE;
struct romfs_super_block *romfsb;
- struct cramfs_super *cramfsb;
+
struct squashfs_super_block *squashfsb;
int nblocks = -1;
unsigned char *buf;
@@ -72,7 +71,6 @@ identify_ramdisk_image(struct file *file, loff_t pos,
return -ENOMEM;
romfsb = (struct romfs_super_block *) buf;
- cramfsb = (struct cramfs_super *) buf;
squashfsb = (struct squashfs_super_block *) buf;
memset(buf, 0xe5, size);
@@ -104,14 +102,6 @@ identify_ramdisk_image(struct file *file, loff_t pos,
goto done;
}
- if (cramfsb->magic == CRAMFS_MAGIC) {
- printk(KERN_NOTICE
- "RAMDISK: cramfs filesystem found at block %d\n",
- start_block);
- nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
- goto done;
- }
-
/* squashfs is at block zero too */
if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
printk(KERN_NOTICE
@@ -122,20 +112,6 @@ identify_ramdisk_image(struct file *file, loff_t pos,
goto done;
}
- /*
- * Read 512 bytes further to check if cramfs is padded
- */
- pos = start_block * BLOCK_SIZE + 0x200;
- kernel_read(file, buf, size, &pos);
-
- if (cramfsb->magic == CRAMFS_MAGIC) {
- printk(KERN_NOTICE
- "RAMDISK: cramfs filesystem found at block %d\n",
- start_block);
- nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
- goto done;
- }
-
/*
* Read block 1 to test for ext2 superblock
*/
--
2.47.0
