On Fri, 29 May 2026 12:58:17 +0100 Gary Guo <[email protected]> wrote:
> On Fri May 29, 2026 at 12:43 PM BST, Onur Özkan wrote: > > Add helper wrappers for SRCU functions that are exposed to Rust > > through generated bindings. > > > > Reviewed-by: Paul E. McKenney <[email protected]> > > Signed-off-by: Onur Özkan <[email protected]> > > --- > > include/linux/srcu.h | 5 +++++ > > rust/helpers/helpers.c | 1 + > > rust/helpers/srcu.c | 30 ++++++++++++++++++++++++++++++ > > 3 files changed, 36 insertions(+) > > create mode 100644 rust/helpers/srcu.c > > > > diff --git a/include/linux/srcu.h b/include/linux/srcu.h > > index 81b1938512d5..790a4ef713c0 100644 > > --- a/include/linux/srcu.h > > +++ b/include/linux/srcu.h > > @@ -57,6 +57,11 @@ int __init_srcu_struct_fast_updown(struct srcu_struct > > *ssp, const char *name, > > #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ > > > > int init_srcu_struct(struct srcu_struct *ssp); > > +static inline int __init_srcu_struct(struct srcu_struct *ssp, const char > > *name, > > + struct lock_class_key *key) > > +{ > > + return init_srcu_struct(ssp); > > +} > > > This looks like a different strategy than, say, how mutex handles lockdep. IMO > the way that mutex handles this is more clear. Initially it was the same strategy, this one was suggested by Paul [1] and it didn't sound like a bad idea to me. Also, in previous revisions, Boqun once said: "Having a "#ifdef" in a function body is generally considered as bad code (I know we have some of these in rust helpers, but helpers are a bit special and maybe we should clean them up). So could you move this function into include/linux/srcutiny.h and include/linux/srcutree.h?" So putting them together, I decided to follow Paul's suggestion. [1]: https://lore.kernel.org/all/05906890-cf06-414c-a625-02f9d7150d57@paulmck-laptop > > If we follow the way mutex is handles this, the `init_srcu_struct` would > always > create lock class key and forward to `__init_srcu_struct`, and > `__init_srcu_struct` is an inline function that either calls > `init_srcu_struct_lockdep` with all args, or discard name/key and forward to > `init_srcu_struct_mutex`. > > This is beneficial because the usage flows one way. You don't have in one > config > `init_srcu_struct` call `__init_srcu_struct` and have the opposite in another > config, which I think can be quite confusing. > > Best, > Gary > > > #ifndef CONFIG_TINY_SRCU > > int init_srcu_struct_fast(struct srcu_struct *ssp); > > int init_srcu_struct_fast_updown(struct srcu_struct *ssp); > > diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c > > index 625921e27dfb..f3562d3b3888 100644 > > --- a/rust/helpers/helpers.c > > +++ b/rust/helpers/helpers.c > > @@ -88,6 +88,7 @@ > > #include "signal.c" > > #include "slab.c" > > #include "spinlock.c" > > +#include "srcu.c" > > #include "sync.c" > > #include "task.c" > > #include "time.c" > > diff --git a/rust/helpers/srcu.c b/rust/helpers/srcu.c > > new file mode 100644 > > index 000000000000..225b3bf9334a > > --- /dev/null > > +++ b/rust/helpers/srcu.c > > @@ -0,0 +1,30 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > + > > +#include <linux/srcu.h> > > + > > +__rust_helper int rust_helper_init_srcu_struct_with_key(struct srcu_struct > > *ssp, > > + const char *name, > > + struct lock_class_key > > *key) > > +{ > > + return __init_srcu_struct(ssp, name, key); > > +} > > + > > +__rust_helper int rust_helper_srcu_read_lock(struct srcu_struct *ssp) > > +{ > > + return srcu_read_lock(ssp); > > +} > > + > > +__rust_helper void rust_helper_srcu_read_unlock(struct srcu_struct *ssp, > > int idx) > > +{ > > + srcu_read_unlock(ssp, idx); > > +} > > + > > +__rust_helper void rust_helper_srcu_barrier(struct srcu_struct *ssp) > > +{ > > + srcu_barrier(ssp); > > +} > > + > > +__rust_helper void rust_helper_synchronize_srcu_expedited(struct > > srcu_struct *ssp) > > +{ > > + synchronize_srcu_expedited(ssp); > > +} > >
