Re: [PATCH v5 1/4] rust: helpers: add SRCU helpers

["Onur Özkan" <work@onurozkan.dev>]

On Wed, 27 May 2026 16:03:30 -0700
"Paul E. McKenney" <paulmck@kernel.org> wrote:

> On Wed, May 27, 2026 at 08:40:42PM +0300, Onur Özkan wrote:
> > Add helper wrappers for SRCU functions that are exposed to Rust
> > through generated bindings.
> > 
> > Signed-off-by: Onur Özkan <work@onurozkan.dev>
> > ---
> >  rust/helpers/helpers.c |  1 +
> >  rust/helpers/srcu.c    | 34 ++++++++++++++++++++++++++++++++++
> >  2 files changed, 35 insertions(+)
> >  create mode 100644 rust/helpers/srcu.c
> > 
> > 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..79dd24a104ef
> > --- /dev/null
> > +++ b/rust/helpers/srcu.c
> > @@ -0,0 +1,34 @@
> > +// 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)
> > +{
> > +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> > +	return __init_srcu_struct(ssp, name, key);
> > +#else /* !CONFIG_DEBUG_LOCK_ALLOC */
> > +	return init_srcu_struct(ssp);
> > +#endif /* CONFIG_DEBUG_LOCK_ALLOC */
> > +}
> 
> Similar to Boqun's feedback on a later patch, could you please make
> these be two functions under the corresponding legs of the existing
> CONFIG_DEBUG_LOCK_ALLOC #ifdef in include/linux/srcu.h?  You are including
> that file above, so it should work well.
> 
> Actually, you could just name thefunction __init_srcu_struct(), use the
> existing definition under #ifdef CONFIG_DEBUG_LOCK_ALLOC, and just create
> the simple wrapper in the other leg of this #ifdef.  That would be more
> aligned with the Linux-kernel coding guidelines and also be less code.
> 
> Or is the "rust_helper_" prefix mandatory?  If so, you could make

That prefix is indeed mandatory.

> rust_helper_init_srcu_struct() be a wrapper for __init_srcu_struct()
> in this file, then just define __init_srcu_struct() as a wrapper around
> init_srcu_struct() in the !CONFIG_DEBUG_LOCK_ALLOC leg of the #ifdef
> in include/linux/srcu.h.

Sure, sounds good to me.

Thanks,
Onur

> 
> As a historical note, I didn't much like this rule 25 years ago, but
> tried a new project both ways, and quickly abandoned the one that used
> #ifdef with abandon.  So I quickly came around to the Linux-kernel way
> of thinking on this particular point, anyway.  ;-)
> 
> 							Thanx, Paul
> 
> > +__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);
> > +}
> > -- 
> > 2.51.2
> >