fs: allow no_seek_end_llseek to actually seek

The user-visible impact of the issue is for example that without this
patch sensors-detect breaks when trying to seek in /dev/cpu/0/cpuid.

'~0ULL' is a 'unsigned long long' that when converted to a loff_t,
which is signed, gets turned into -1. later in vfs_setpos we have
'if (offset > maxsize)', which makes it always return EINVAL.

Fixes: b25472f9b9 ("new helpers: no_seek_end_llseek{,_size}()")
Signed-off-by: Wouter van Kesteren <woutershep@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/read_write.c

@@ -17,6 +17,7 @@
 #include <linux/splice.h>
 #include <linux/compat.h>
 #include <linux/mount.h>
+#include <linux/fs.h>
 #include "internal.h"
 
 #include <asm/uaccess.h>
@@ -183,7 +184,7 @@ loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)
 	switch (whence) {
 	case SEEK_SET: case SEEK_CUR:
 		return generic_file_llseek_size(file, offset, whence,
-						~0ULL, 0);
+						OFFSET_MAX, 0);
 	default:
 		return -EINVAL;
 	}