On 5/26/23 11:05, Peter Zijlstra wrote:
Use __attribute__((__cleanup__(func))) to buid various guards: - ptr_guard() - void_guard() / void_scope() - lock_guard() / lock_scope() - double_lock_guard() / double_lock_scope() Where the _guard thingies are variables with scope-based cleanup and the _scope thingies are basically do-once for-loops with the same. The CPP is rather impenetrable -- but I'll attempt to write proper comments if/when people think this is worth pursuing. Actual usage in the next patch Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> --- include/linux/compiler_attributes.h | 2 include/linux/irqflags.h | 7 ++ include/linux/guards.h | 118 ++++++++++++++++++++++++++++++++++++ include/linux/mutex.h | 5 + include/linux/preempt.h | 4 + include/linux/rcupdate.h | 3 include/linux/sched/task.h | 2 include/linux/spinlock.h | 23 +++++++ 8 files changed, 164 insertions(+)
That is an interesting idea and may help to simplify some of the common code patterns that we have in the kernel. The macros are a bit hard to read and understand though I thought I got a rough idea of what they are trying to do.
BTW, do we have a use case for double_lock_guard/double_lock_scope? I can envision a nested lock_scope inside a lock_scope, but taking 2 auto locks of the same type at init time and then unlock them at exit just doesn't make sense to me.
Cheers, Longman
