On Thu, Apr 30, 2020 at 12:23 PM Luck, Tony <tony.luck@xxxxxxxxx> wrote: > > On Thu, Apr 30, 2020 at 11:42:20AM -0700, Andy Lutomirski wrote: > > I suppose there could be a consistent naming like this: > > > > copy_from_user() > > copy_to_user() > > > > copy_from_unchecked_kernel_address() [what probe_kernel_read() is] > > copy_to_unchecked_kernel_address() [what probe_kernel_write() is] > > > > copy_from_fallible() [from a kernel address that can fail to a kernel > > address that can't fail] > > copy_to_fallible() [the opposite, but hopefully identical to memcpy() on x86] > > > > copy_from_fallible_to_user() > > copy_from_user_to_fallible() > > > > These names are fairly verbose and could probably be improved. > > How about > > try_copy_catch(void *dst, void *src, size_t count, int *fault) > > returns number of bytes not-copied (like copy_to_user etc). > > if return is not zero, "fault" tells you what type of fault > cause the early stop (#PF, #MC). I do like try_copy_catch() for the case when neither of the buffers are __user (like in the pmem driver) and _copy_to_iter_fallible() (plus all the helpers it implies) for the other cases. copy_to_user_fallible copy_fallible_to_page copy_pipe_to_iter_fallible ...because the mmu-fault handling is an aspect of "_user" and fallible implies other source fault reasons. It does leave a gap if an architecture has a concept of a fallible write, but that seems like something that will be handled asynchronously and not subject to this interface.
