On Wed, 2020-08-19 at 21:54 +0530, Allen wrote:

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Since both threads seem to have petered out, let me suggest in
kernel.h:

#define cast_out(ptr, container, member) \
    container_of(ptr, typeof(*container), member)

It does what you want, the argument order is the same as
container_of with the only difference being you name the
containing structure instead of having to specify its type.

Not to incessantly bike shed on the naming, but I don't like
cast_out, it's not very descriptive. And it has connotations of
getting rid of something, which isn't really true.

Um, I thought it was exactly descriptive: you're casting to the
outer container.  I thought about following the C++ dynamic casting
style, so out_cast(), but that seemed a bit pejorative.  What about
outer_cast()?

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FWIW, I like the from_ part of the original naming, as it has
some clues as to what is being done here. Why not just
from_container()? That should immediately tell people what it
does without having to look up the implementation, even before
this becomes a part of the accepted coding norm.

I'm not opposed to container_from() but it seems a little less
descriptive than outer_cast() but I don't really care.  I always
have to look up container_of() when I'm using it so this would just
be another macro of that type ...

 So far we have a few which have been suggested as replacement
for from_tasklet()

- out_cast() or outer_cast()
- from_member().
- container_from() or from_container()

from_container() sounds fine, would trimming it a bit work? like
from_cont().

I'm fine with container_from().  It's the same form as container_of()
and I think we need urgent agreement to not stall everything else so
the most innocuous name is likely to get the widest acceptance.

James