sys/queue.h: Add {LIST,TAILQ}_REPLACE().

[des]

Summary

MFC after: 1 week
Obtained from: NetBSD
Sponsored by: Klara, Inc.

[imp]

Seems OK to me: doesn't make things worse, provides a good function not. yet available, and is compatible with at least one other system.

[cperciva]

share/man/man3/queue.3

975

If I were writing this myself, I would add "The element .Fa new must not already be on a list." for clarity, but it's probably not worth diverging from NetBSD.

sys/sys/queue.h

883

I would have written this as

(elm2)->field.tqe_next = (elm)->field.tqe_next;
if ((elm2)->field.tqe_next != TAILQ_END(head))
    ....

since I think that's a bit clearer with all the added parentheses associated with macros, but this is also fine.

[jrtc27]

sys/sys/queue.h

614

QMD_LIST_CHECK_*?

614–616

Use LIST_NEXT instead of direct le_next accesses

619

TRASHIT?

882

Same comments as LIST

[des]

incorporate review feedback

[des]

I don't mind diverging from NetBSD if it's an improvement, we've already diverged quite a bit.

[des]

oops

[cperciva]

LGTM.

[cperciva]

sys/sys/queue.h

620

This could be s/elm/elm2/ but since they're equal at this point it doesn't matter.