centos man page for __check_region

__CHECK_REGION(9)						Hardware Interfaces						 __CHECK_REGION(9)

NAME
       __check_region - check if a resource region is busy or free

SYNOPSIS
       int __check_region(struct resource * parent, resource_size_t start, resource_size_t n);

ARGUMENTS
       parent
	   parent resource descriptor

       start
	   resource start address

       n
	   resource region size

DESCRIPTION
       Returns 0 if the region is free at the moment it is checked, returns -EBUSY if the region is busy.

NOTE
       This function is deprecated because its use is racy. Even if it returns 0, a subsequent call to request_region may fail because another
       driver etc. just allocated the region. Do NOT use it. It will be removed from the kernel.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							 __CHECK_REGION(9)