[PATCH] BLOCK: Move the loop device ioctl compat stuff to the loop driver [try #6]

Move the loop device ioctl compat stuff from fs/compat_ioctl.c to the loop
driver so that the loop header file doesn't need to be included.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 160 insertions, 74 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 68b0471..d6bb8da 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -66,6 +66,7 @@
 #include <linux/swap.h>
 #include <linux/slab.h>
 #include <linux/loop.h>
+#include <linux/compat.h>
 #include <linux/suspend.h>
 #include <linux/writeback.h>
 #include <linux/buffer_head.h>		/* for invalidate_bdev() */
@@ -1165,6 +1166,162 @@ static int lo_ioctl(struct inode * inode, struct file * file,
 	return err;
 }
 
+#ifdef CONFIG_COMPAT
+struct compat_loop_info {
+	compat_int_t	lo_number;      /* ioctl r/o */
+	compat_dev_t	lo_device;      /* ioctl r/o */
+	compat_ulong_t	lo_inode;       /* ioctl r/o */
+	compat_dev_t	lo_rdevice;     /* ioctl r/o */
+	compat_int_t	lo_offset;
+	compat_int_t	lo_encrypt_type;
+	compat_int_t	lo_encrypt_key_size;    /* ioctl w/o */
+	compat_int_t	lo_flags;       /* ioctl r/o */
+	char		lo_name[LO_NAME_SIZE];
+	unsigned char	lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
+	compat_ulong_t	lo_init[2];
+	char		reserved[4];
+};
+
+/*
+ * Transfer 32-bit compatibility structure in userspace to 64-bit loop info
+ * - noinlined to reduce stack space usage in main part of driver
+ */
+static noinline int
+loop_info64_from_compat(const struct compat_loop_info *arg,
+			struct loop_info64 *info64)
+{
+	struct compat_loop_info info;
+
+	if (copy_from_user(&info, arg, sizeof(info)))
+		return -EFAULT;
+
+	memset(info64, 0, sizeof(*info64));
+	info64->lo_number = info.lo_number;
+	info64->lo_device = info.lo_device;
+	info64->lo_inode = info.lo_inode;
+	info64->lo_rdevice = info.lo_rdevice;
+	info64->lo_offset = info.lo_offset;
+	info64->lo_sizelimit = 0;
+	info64->lo_encrypt_type = info.lo_encrypt_type;
+	info64->lo_encrypt_key_size = info.lo_encrypt_key_size;
+	info64->lo_flags = info.lo_flags;
+	info64->lo_init[0] = info.lo_init[0];
+	info64->lo_init[1] = info.lo_init[1];
+	if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
+		memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE);
+	else
+		memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE);
+	memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE);
+	return 0;
+}
+
+/*
+ * Transfer 64-bit loop info to 32-bit compatibility structure in userspace
+ * - noinlined to reduce stack space usage in main part of driver
+ */
+static noinline int
+loop_info64_to_compat(const struct loop_info64 *info64,
+		      struct compat_loop_info __user *arg)
+{
+	struct compat_loop_info info;
+
+	memset(&info, 0, sizeof(info));
+	info.lo_number = info64->lo_number;
+	info.lo_device = info64->lo_device;
+	info.lo_inode = info64->lo_inode;
+	info.lo_rdevice = info64->lo_rdevice;
+	info.lo_offset = info64->lo_offset;
+	info.lo_encrypt_type = info64->lo_encrypt_type;
+	info.lo_encrypt_key_size = info64->lo_encrypt_key_size;
+	info.lo_flags = info64->lo_flags;
+	info.lo_init[0] = info64->lo_init[0];
+	info.lo_init[1] = info64->lo_init[1];
+	if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
+		memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
+	else
+		memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE);
+	memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
+
+	/* error in case values were truncated */
+	if (info.lo_device != info64->lo_device ||
+	    info.lo_rdevice != info64->lo_rdevice ||
+	    info.lo_inode != info64->lo_inode ||
+	    info.lo_offset != info64->lo_offset ||
+	    info.lo_init[0] != info64->lo_init[0] ||
+	    info.lo_init[1] != info64->lo_init[1])
+		return -EOVERFLOW;
+
+	if (copy_to_user(arg, &info, sizeof(info)))
+		return -EFAULT;
+	return 0;
+}
+
+static int
+loop_set_status_compat(struct loop_device *lo,
+		       const struct compat_loop_info __user *arg)
+{
+	struct loop_info64 info64;
+	int ret;
+
+	ret = loop_info64_from_compat(arg, &info64);
+	if (ret < 0)
+		return ret;
+	return loop_set_status(lo, &info64);
+}
+
+static int
+loop_get_status_compat(struct loop_device *lo,
+		       struct compat_loop_info __user *arg)
+{
+	struct loop_info64 info64;
+	int err = 0;
+
+	if (!arg)
+		err = -EINVAL;
+	if (!err)
+		err = loop_get_status(lo, &info64);
+	if (!err)
+		err = loop_info64_to_compat(&info64, arg);
+	return err;
+}
+
+static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file->f_dentry->d_inode;
+	struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
+	int err;
+
+	lock_kernel();
+	switch(cmd) {
+	case LOOP_SET_STATUS:
+		mutex_lock(&lo->lo_ctl_mutex);
+		err = loop_set_status_compat(
+			lo, (const struct compat_loop_info __user *) arg);
+		mutex_unlock(&lo->lo_ctl_mutex);
+		break;
+	case LOOP_GET_STATUS:
+		mutex_lock(&lo->lo_ctl_mutex);
+		err = loop_get_status_compat(
+			lo, (struct compat_loop_info __user *) arg);
+		mutex_unlock(&lo->lo_ctl_mutex);
+		break;
+	case LOOP_CLR_FD:
+	case LOOP_GET_STATUS64:
+	case LOOP_SET_STATUS64:
+		arg = (unsigned long) compat_ptr(arg);
+	case LOOP_SET_FD:
+	case LOOP_CHANGE_FD:
+		err = lo_ioctl(inode, file, cmd, arg);
+		break;
+	default:
+		err = -ENOIOCTLCMD;
+		break;
+	}
+	unlock_kernel();
+	return err;
+}
+#endif
+
 static int lo_open(struct inode *inode, struct file *file)
 {
 	struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
@@ -1192,6 +1349,9 @@ static struct block_device_operations lo_fops = {
 	.open =		lo_open,
 	.release =	lo_release,
 	.ioctl =	lo_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl =	lo_compat_ioctl,
+#endif
 };
 
 /*
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index ab74c9b..3b0cf7f 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -40,7 +40,6 @@
 #include <linux/if_pppox.h>
 #include <linux/mtio.h>
 #include <linux/cdrom.h>
-#include <linux/loop.h>
 #include <linux/auto_fs.h>
 #include <linux/auto_fs4.h>
 #include <linux/tty.h>
@@ -1214,71 +1213,6 @@ static int cdrom_ioctl_trans(unsigned int fd, unsigned int cmd, unsigned long ar
 	return err;
 }
 
-struct loop_info32 {
-	compat_int_t	lo_number;      /* ioctl r/o */
-	compat_dev_t	lo_device;      /* ioctl r/o */
-	compat_ulong_t	lo_inode;       /* ioctl r/o */
-	compat_dev_t	lo_rdevice;     /* ioctl r/o */
-	compat_int_t	lo_offset;
-	compat_int_t	lo_encrypt_type;
-	compat_int_t	lo_encrypt_key_size;    /* ioctl w/o */
-	compat_int_t	lo_flags;       /* ioctl r/o */
-	char		lo_name[LO_NAME_SIZE];
-	unsigned char	lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
-	compat_ulong_t	lo_init[2];
-	char		reserved[4];
-};
-
-static int loop_status(unsigned int fd, unsigned int cmd, unsigned long arg)
-{
-	mm_segment_t old_fs = get_fs();
-	struct loop_info l;
-	struct loop_info32 __user *ul;
-	int err = -EINVAL;
-
-	ul = compat_ptr(arg);
-	switch(cmd) {
-	case LOOP_SET_STATUS:
-		err = get_user(l.lo_number, &ul->lo_number);
-		err |= __get_user(l.lo_device, &ul->lo_device);
-		err |= __get_user(l.lo_inode, &ul->lo_inode);
-		err |= __get_user(l.lo_rdevice, &ul->lo_rdevice);
-		err |= __copy_from_user(&l.lo_offset, &ul->lo_offset,
-		        8 + (unsigned long)l.lo_init - (unsigned long)&l.lo_offset);
-		if (err) {
-			err = -EFAULT;
-		} else {
-			set_fs (KERNEL_DS);
-			err = sys_ioctl (fd, cmd, (unsigned long)&l);
-			set_fs (old_fs);
-		}
-		break;
-	case LOOP_GET_STATUS:
-		set_fs (KERNEL_DS);
-		err = sys_ioctl (fd, cmd, (unsigned long)&l);
-		set_fs (old_fs);
-		if (!err) {
-			err = put_user(l.lo_number, &ul->lo_number);
-			err |= __put_user(l.lo_device, &ul->lo_device);
-			err |= __put_user(l.lo_inode, &ul->lo_inode);
-			err |= __put_user(l.lo_rdevice, &ul->lo_rdevice);
-			err |= __copy_to_user(&ul->lo_offset, &l.lo_offset,
-				(unsigned long)l.lo_init - (unsigned long)&l.lo_offset);
-			if (err)
-				err = -EFAULT;
-		}
-		break;
-	default: {
-		static int count;
-		if (++count <= 20)
-			printk("%s: Unknown loop ioctl cmd, fd(%d) "
-			       "cmd(%08x) arg(%08lx)\n",
-			       __FUNCTION__, fd, cmd, arg);
-	}
-	}
-	return err;
-}
-
 #ifdef CONFIG_VT
 
 static int vt_check(struct file *file)
@@ -2808,8 +2742,6 @@ HANDLE_IOCTL(MTIOCGET32, mt_ioctl_trans)
 HANDLE_IOCTL(MTIOCPOS32, mt_ioctl_trans)
 HANDLE_IOCTL(CDROMREADAUDIO, cdrom_ioctl_trans)
 HANDLE_IOCTL(CDROM_SEND_PACKET, cdrom_ioctl_trans)
-HANDLE_IOCTL(LOOP_SET_STATUS, loop_status)
-HANDLE_IOCTL(LOOP_GET_STATUS, loop_status)
 #define AUTOFS_IOC_SETTIMEOUT32 _IOWR(0x93,0x64,unsigned int)
 HANDLE_IOCTL(AUTOFS_IOC_SETTIMEOUT32, ioc_settimeout)
 #ifdef CONFIG_VT
diff --git a/include/linux/compat_ioctl.h b/include/linux/compat_ioctl.h
index bea0255..98d40e0 100644
--- a/include/linux/compat_ioctl.h
+++ b/include/linux/compat_ioctl.h
@@ -395,12 +395,6 @@ COMPATIBLE_IOCTL(DVD_WRITE_STRUCT)
 COMPATIBLE_IOCTL(DVD_AUTH)
 /* pktcdvd */
 COMPATIBLE_IOCTL(PACKET_CTRL_CMD)
-/* Big L */
-ULONG_IOCTL(LOOP_SET_FD)
-ULONG_IOCTL(LOOP_CHANGE_FD)
-COMPATIBLE_IOCTL(LOOP_CLR_FD)
-COMPATIBLE_IOCTL(LOOP_GET_STATUS64)
-COMPATIBLE_IOCTL(LOOP_SET_STATUS64)
 /* Big A */
 /* sparc only */
 /* Big Q for sound/OSS */