On Fri, Aug 1, 2025 at 4:16 AM Steven Rostedt <rost...@goodmis.org> wrote: > > From: Steven Rostedt <rost...@goodmis.org> > > Several functions need to call btf_put() on the btf pointer before it > returns leading to using "goto" branches to jump to the end to call > btf_put(btf). This can be simplified by introducing DEFINE_FREE() to allow > functions to define the btf descriptor with: > > struct btf *btf __free(btf_put) = NULL; > > Then the btf descriptor will always have btf_put() called on it if it > isn't NULL or ERR before exiting the function. > > Where needed, no_free_ptr(btf) is used to assign the btf descriptor to a > pointer that will be used outside the function. > > Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org> > --- > include/linux/btf.h | 4 +++ > kernel/bpf/btf.c | 56 +++++++++++-------------------------- > kernel/trace/trace_btf.c | 15 +++++----- > kernel/trace/trace_output.c | 8 ++---- > 4 files changed, 31 insertions(+), 52 deletions(-) > > diff --git a/include/linux/btf.h b/include/linux/btf.h > index b2983706292f..e118c69c4996 100644 > --- a/include/linux/btf.h > +++ b/include/linux/btf.h > @@ -8,6 +8,7 @@ > #include <linux/bpfptr.h> > #include <linux/bsearch.h> > #include <linux/btf_ids.h> > +#include <linux/cleanup.h> > #include <uapi/linux/btf.h> > #include <uapi/linux/bpf.h> > > @@ -150,6 +151,9 @@ struct btf *btf_get_by_fd(int fd); > int btf_get_info_by_fd(const struct btf *btf, > const union bpf_attr *attr, > union bpf_attr __user *uattr); > + > +DEFINE_FREE(btf_put, struct btf *, if (!IS_ERR_OR_NULL(_T)) btf_put(_T)) > + > /* Figure out the size of a type_id. If type_id is a modifier > * (e.g. const), it will be resolved to find out the type with size. > * > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index 1d2cf898e21e..480657912c96 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -3788,7 +3788,7 @@ static int btf_parse_kptr(const struct btf *btf, struct > btf_field *field, > /* If a matching btf type is found in kernel or module BTFs, kptr_ref > * is that BTF, otherwise it's program BTF > */ > - struct btf *kptr_btf; > + struct btf *kptr_btf __free(btf_put) = NULL;
Sorry I hate this __free() style. It's not a simplification, but an obfuscation of code and logic. -- pw-bot: cr
