| Message ID | 20240627152340.82413-4-mathieu.desnoyers@efficios.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Faultable Tracepoints | expand |
On Thu, 27 Jun 2024 11:23:35 -0400 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote: > To cover scenarios where the scope of the guard differs from the scope > of its activation, introduce DEFINE_INACTIVE_GUARD() and activate_guard(). > > Here is an example use for a conditionally activated guard variable: > > void func(bool a) > { > DEFINE_INACTIVE_GUARD(preempt_notrace, myguard); > > [...] > if (a) { > might_sleep(); > activate_guard(preempt_notrace, myguard)(); > } > [ protected code ] > } > Hi Mathieu, The three cleanup patches fail to apply (I believe one has already been fixed by Ingo too). Could you have the clean up patches be a separate series that is likely to get in, especially since it's more of a moving target. Thanks, -- Steve
On 2024-08-20 01:00, Steven Rostedt wrote: > On Thu, 27 Jun 2024 11:23:35 -0400 > Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote: > >> To cover scenarios where the scope of the guard differs from the scope >> of its activation, introduce DEFINE_INACTIVE_GUARD() and activate_guard(). >> >> Here is an example use for a conditionally activated guard variable: >> >> void func(bool a) >> { >> DEFINE_INACTIVE_GUARD(preempt_notrace, myguard); >> >> [...] >> if (a) { >> might_sleep(); >> activate_guard(preempt_notrace, myguard)(); >> } >> [ protected code ] >> } >> > > Hi Mathieu, > > The three cleanup patches fail to apply (I believe one has already been > fixed by Ingo too). Could you have the clean up patches be a separate > series that is likely to get in, especially since it's more of a moving > target. Then it would make sense to split this into two series: one for the guard stuff, and one for tracing which depends on the first one. I'll do that. Mathieu > > Thanks, > > -- Steve
diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h index 04f03ad5f25d..d6a3d8099d77 100644 --- a/include/linux/cleanup.h +++ b/include/linux/cleanup.h @@ -146,12 +146,20 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ * similar to scoped_guard(), except it does fail when the lock * acquire fails. * + * DEFINE_INACTIVE_GUARD(name, var): + * define an inactive guard variable in a given scope, initialized to NULL. + * + * activate_guard(name, var)(args...): + * activate a guard variable with its constructor, if it is not already + * activated. */ #define DECLARE_GUARD(_name, _type, _lock, _unlock) \ DECLARE_CLASS(_name, _type, if (_T) { _unlock; }, ({ _lock; _T; }), _type _T); \ static inline void * class_##_name##_lock_ptr(class_##_name##_t *_T) \ - { return *_T; } + { return *_T; } \ + static inline class_##_name##_t class_##_name##_null(void) \ + { return NULL; } #define DECLARE_GUARD_COND(_name, _ext, _condlock) \ EXTEND_CLASS(_name, _ext, \ @@ -175,6 +183,14 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ if (!__guard_ptr(_name)(&scope)) _fail; \ else +#define DEFINE_INACTIVE_GUARD(_name, _var) \ + class_##_name##_t _var __cleanup(class_##_name##_destructor) = \ + class_##_name##_null() + +#define activate_guard(_name, _var) \ + if (!class_##_name##_lock_ptr(&(_var))) \ + _var = class_##_name##_constructor + /* * Additional helper macros for generating lock guards with types, either for * locks that don't have a native type (eg. RCU, preempt) or those that need a @@ -209,6 +225,11 @@ static inline void class_##_name##_destructor(class_##_name##_t *_T) \ static inline void *class_##_name##_lock_ptr(class_##_name##_t *_T) \ { \ return _T->lock; \ +} \ +static inline class_##_name##_t class_##_name##_null(void) \ +{ \ + class_##_name##_t _t = { .lock = NULL }; \ + return _t; \ }
To cover scenarios where the scope of the guard differs from the scope of its activation, introduce DEFINE_INACTIVE_GUARD() and activate_guard(). Here is an example use for a conditionally activated guard variable: void func(bool a) { DEFINE_INACTIVE_GUARD(preempt_notrace, myguard); [...] if (a) { might_sleep(); activate_guard(preempt_notrace, myguard)(); } [ protected code ] } Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Kees Cook <keescook@chromium.org> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Sean Christopherson <seanjc@google.com> --- include/linux/cleanup.h | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-)