From: Linus Torvalds > Sent: 01 March 2022 23:03 > > On Tue, Mar 1, 2022 at 2:58 PM David Laight <David.Laight@xxxxxxxxxx> wrote: > > > > Can it be resolved by making: > > #define list_entry_is_head(pos, head, member) ((pos) == NULL) > > and double-checking that it isn't used anywhere else (except in > > the list macros themselves). > > Well, yes, except for the fact that then the name is entirely misleading... > > And somebody possibly uses it together with list_first_entry() etc, so > it really is completely broken to mix that change with the list > traversal change. Probably true :-( Actually adding list_entry_not_found() as a synonym for list_entry_is_head() and changing the 25ish places that use it after a loop might work. Once that is done the loop can be changed at the same time as list_entry_not_found(). That won't affect the in-tree callers. (and my out of tree modules don't use those lists - so I don't care about that!) Having said that there are so few users of list_entry_is_head() it is reasonable to generate two new names. One for use after list_for_each_entry() and one for list_next_entry(). Then the change all the call sites. After that list_entry_is_head() can be deleted - breaking out of tree compiles. Finally list_for_each_entry() can be rewritten to set NULL at the end of the list. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
