focal (9) vslock.9freebsd.gz

NAME

     vslock, vsunlock — lock/unlock user space addresses in memory

SYNOPSIS

     #include <sys/param.h>
     #include <sys/proc.h>
     #include <vm/vm.h>
     #include <vm/vm_extern.h>

     int
     vslock(void *addr, size_t len);

     void
     vsunlock(void *addr, size_t len);

DESCRIPTION

     The vslock() and vsunlock() functions respectively lock and unlock a range of addresses belonging to the
     currently running process into memory.  The actual amount of memory locked is a multiple of the machine's
     page size.  The starting page number is computed by truncating addr to the nearest preceding page boundary,
     and by rounding up addr + len to the next page boundary.  The process context to use for this operation is
     taken from the global variable curproc.

RETURN VALUES

     The vslock() function will return 0 on success, otherwise it will return one of the errors listed below.

ERRORS

     The vslock() function will fail if:

     [EINVAL]           The addr and len parameters specify a memory range that wraps around the end of the
                        machine address space.

     [ENOMEM]           The size of the specified address range exceeds the system limit on locked memory.

     [EFAULT]           Some portion of the indicated address range is not allocated.  There was an error
                        faulting/mapping a page.