From: Čestmír Kalina <ckalina@xxxxxxxxxx> kabi: introduce RH_KABI_USE_AUX_PTR Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2024595 Upstream Status: RHEL only commit 194de3042cda2e21a14b504965b4c463b47de73c Author: Jiri Benc <jbenc@xxxxxxxxxx> Date: Wed, 1 Apr 2020 13:04:15 -0400 It's hard to predict the number of changes required in a struct. We do our best by reserving fields by RH_KABI_RESERVE but sometimes they run out. If that's going to happen, the last two reserved fields can be changed into an aux struct mechanism. Introduce a macro that does that. Example: there's this struct: struct foo { ... RH_KABI_USE(1, int a) RH_KABI_USE(2, int b) RH_KABI_RESERVE(3) RH_KABI_RESERVE(4) }; and a need to add field 'int c', while we expect further additions. It can be now done in this way: struct foo_rh { int c; }; struct foo { ... RH_KABI_USE(1, int a) RH_KABI_USE(2, int b) RH_KABI_USE_AUX_PTR(3, 4, foo) }; RH-Signed-off-by: Jiri Benc <jbenc@xxxxxxxxxx> Signed-off-by: Čestmír Kalina <ckalina@xxxxxxxxxx> Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> diff --git a/include/linux/rh_kabi.h b/include/linux/rh_kabi.h index blahblah..blahblah 100644 --- a/include/linux/rh_kabi.h +++ b/include/linux/rh_kabi.h @@ -388,6 +388,15 @@ #define RH_KABI_AUX_EMBED(_struct) \ _RH_KABI_AUX_EMBED(_struct); +/* + * If there is a post-kABI freeze need of RH_KABI_AUX_PTR and there are + * still two reserved fields available, they can be converted by + * RH_KABI_USE_AUX_PTR. + */ +#define RH_KABI_USE_AUX_PTR(n1, n2, _struct) \ + RH_KABI_USE(n1, n2, \ + struct { RH_KABI_AUX_PTR(_struct) }) + /* * RH_KABI_AUX_SET_SIZE calculates and sets the size of the extended struct and * stores it in the size_rh field for structs that are dynamically allocated. -- https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1530 _______________________________________________ kernel mailing list -- kernel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to kernel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/kernel@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
