Release memory allocated by vmalloc
void vfree(const void * addr);
addr
memory base address
Free the virtually continuous memory area starting at addr, as obtained from vmalloc, vmalloc_32 or __vmalloc. If addr is NULL, no operation is performed.
Must not be called in NMI context (strictly speaking, only if we don't have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling conventions for vfree arch-depenedent would be a really bad idea)
assumes that the object at *addr has a size >= sizeof(llist_node)