From: Dan Carpenter > Sent: 07 March 2022 15:01 > > Updating this API is risky because some places rely on the old behavior > and not all of them have been updated. Here are some additional places > you might want to change. I really can't help thinking that trying to merge this patch is actually impossible. It affects far too many different parts of the tree. Since (I believe) this is a doubly linked list with forwards and backwards pointers that point to a 'node' (not that there is a nice comment to that effect in the header - and there are lots of ways to do linked lists) the 'head' pretty much has to be a 'node'. I'd write the following new defines (but I might be using the old names here): list_first(head, field) First item, NULL if empty. list_last(head, field) Last item NULL if empty. list_next(head, item, field) Item after 'item', NULL if last. list_prev(head, item. field) Item before 'item', NULL if first. You get (something like): #define list_first(head, field) \ head->next == &head ? NULL : list_item(head->next, field) (probably needs typeof(item) from somewhere). The iterator loop is then just: #define loop_iterate(item, head, field) \ for (item = list_first(head, field); item; \ item = list_next(head, item, field) I'm not sure, but making the 'head' be a structure that contains a single member that is a 'node' might help type checking. Then all the code that uses the current defines can slowly be moved over (probably a couple of releases) before the existing defines are deleted. That should simplify all the open-coded search loops that are just as likely to be buggy (possibly more so). David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
