compat: move FS_IOC_RESVSP_32 handling to fs/ioctl.c

... and lose the ridiculous games with compat_alloc_user_space()
there.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

fs/compat_ioctl.c

@@ -467,41 +467,6 @@ static int rtc_ioctl(struct file *file,
 	return -ENOIOCTLCMD;
 }
 
-/* on ia32 l_start is on a 32-bit boundary */
-#if defined(CONFIG_X86_64)
-struct space_resv_32 {
-	__s16		l_type;
-	__s16		l_whence;
-	__s64		l_start	__attribute__((packed));
-			/* len == 0 means until end of file */
-	__s64		l_len __attribute__((packed));
-	__s32		l_sysid;
-	__u32		l_pid;
-	__s32		l_pad[4];	/* reserve area */
-};
-
-#define FS_IOC_RESVSP_32		_IOW ('X', 40, struct space_resv_32)
-#define FS_IOC_RESVSP64_32	_IOW ('X', 42, struct space_resv_32)
-
-/* just account for different alignment */
-static int compat_ioctl_preallocate(struct file *file,
-			struct space_resv_32    __user *p32)
-{
-	struct space_resv	__user *p = compat_alloc_user_space(sizeof(*p));
-
-	if (copy_in_user(&p->l_type,	&p32->l_type,	sizeof(s16)) ||
-	    copy_in_user(&p->l_whence,	&p32->l_whence, sizeof(s16)) ||
-	    copy_in_user(&p->l_start,	&p32->l_start,	sizeof(s64)) ||
-	    copy_in_user(&p->l_len,	&p32->l_len,	sizeof(s64)) ||
-	    copy_in_user(&p->l_sysid,	&p32->l_sysid,	sizeof(s32)) ||
-	    copy_in_user(&p->l_pid,	&p32->l_pid,	sizeof(u32)) ||
-	    copy_in_user(&p->l_pad,	&p32->l_pad,	4*sizeof(u32)))
-		return -EFAULT;
-
-	return ioctl_preallocate(file, p);
-}
-#endif
-
 /*
  * simple reversible transform to make our table more evenly
  * distributed after sorting.

fs/ioctl.c

@@ -491,6 +491,35 @@ int ioctl_preallocate(struct file *filp, void __user *argp)
 	return vfs_fallocate(filp, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
 }
 
+/* on ia32 l_start is on a 32-bit boundary */
+#if defined CONFIG_COMPAT && defined(CONFIG_X86_64)
+/* just account for different alignment */
+int compat_ioctl_preallocate(struct file *file,
+				struct space_resv_32 __user *argp)
+{
+	struct inode *inode = file_inode(file);
+	struct space_resv_32 sr;
+
+	if (copy_from_user(&sr, argp, sizeof(sr)))
+		return -EFAULT;
+
+	switch (sr.l_whence) {
+	case SEEK_SET:
+		break;
+	case SEEK_CUR:
+		sr.l_start += file->f_pos;
+		break;
+	case SEEK_END:
+		sr.l_start += i_size_read(inode);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return vfs_fallocate(file, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
+}
+#endif
+
 static int file_ioctl(struct file *filp, unsigned int cmd,
 		unsigned long arg)
 {

include/linux/falloc.h

@@ -29,4 +29,24 @@ struct space_resv {
 					 FALLOC_FL_INSERT_RANGE |	\
 					 FALLOC_FL_UNSHARE_RANGE)
 
+/* on ia32 l_start is on a 32-bit boundary */
+#if defined(CONFIG_X86_64)
+struct space_resv_32 {
+	__s16		l_type;
+	__s16		l_whence;
+	__s64		l_start	__attribute__((packed));
+			/* len == 0 means until end of file */
+	__s64		l_len __attribute__((packed));
+	__s32		l_sysid;
+	__u32		l_pid;
+	__s32		l_pad[4];	/* reserve area */
+};
+
+#define FS_IOC_RESVSP_32		_IOW ('X', 40, struct space_resv_32)
+#define FS_IOC_RESVSP64_32	_IOW ('X', 42, struct space_resv_32)
+
+int compat_ioctl_preallocate(struct file *, struct space_resv_32 __user *);
+
+#endif
+
 #endif /* _FALLOC_H_ */