Instead of all of these games with dropping and reacquiring mmap_sem and
adding other locks, or deferring the work, why don't we just do a
get_user_pages()? Something along the lines of:
while (1) {
ret = cmpxchg(addr)
if (!ret)
break;
if (ret == -EFAULT)
get_user_pages(addr);
}
Does anybody see a problem with that?
