Type of access:
VERIFY_WRITE. Note that
VERIFY_WRITE is a superset of
VERIFY_READ - if it is safe
to write to a block, it is always safe to read from it.
User space pointer to start of block to check
Size of block to check
Checks if a pointer to a block of memory in user space is valid.
Returns true (nonzero) if the memory block may be valid, false (zero) if it is definitely invalid.
Note that, depending on architecture, this function probably just checks that the pointer is in the user space range - after calling this function, memory access functions may still return -EFAULT.