On Fri, May 29, 2026 at 04:39:51PM +0300, Onur Özkan wrote: > Add helper wrappers for SRCU functions that are exposed to Rust > through generated bindings. > > Signed-off-by: Onur Özkan <[email protected]> > > --- > include/linux/srcu.h | 29 ++++++++++++++++++++--------- > kernel/rcu/srcutiny.c | 10 +++++----- > kernel/rcu/srcutree.c | 9 +++++---- > rust/helpers/helpers.c | 1 + > rust/helpers/srcu.c | 30 ++++++++++++++++++++++++++++++ > 5 files changed, 61 insertions(+), 18 deletions(-) > create mode 100644 rust/helpers/srcu.c
On the next version, please split the rust/helpers changes into a
separate patch. It looks like the simplification to SRCU adds code
rather than deleting it?
But let me see if I understand the structure.
> diff --git a/include/linux/srcu.h b/include/linux/srcu.h
> index 81b1938512d5..a028a5b5ebef 100644
> --- a/include/linux/srcu.h
> +++ b/include/linux/srcu.h
> @@ -25,20 +25,19 @@ context_lock_struct(srcu_struct, __reentrant_ctx_lock);
>
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
>
> -int __init_srcu_struct(struct srcu_struct *ssp, const char *name, struct
> lock_class_key *key);
> +int init_srcu_struct_lockdep(struct srcu_struct *ssp, const char *name,
> + struct lock_class_key *key);
> +static inline int __init_srcu_struct(struct srcu_struct *ssp, const char
> *name,
> + struct lock_class_key *key)
> +{
> + return init_srcu_struct_lockdep(ssp, name, key);
> +}
__init_srcu_struct() invokes init_srcu_struct_lockdep()...
> #ifndef CONFIG_TINY_SRCU
> int __init_srcu_struct_fast(struct srcu_struct *ssp, const char *name,
> struct lock_class_key *key);
> int __init_srcu_struct_fast_updown(struct srcu_struct *ssp, const char *name,
> struct lock_class_key *key);
> #endif // #ifndef CONFIG_TINY_SRCU
>
> -#define init_srcu_struct(ssp) \
> -({ \
> - static struct lock_class_key __srcu_key; \
> - \
> - __init_srcu_struct((ssp), #ssp, &__srcu_key); \
> -})
init_srcu_struct() invokes __init_srcu_struct()... (moved)
> #define init_srcu_struct_fast(ssp) \
> ({ \
> static struct lock_class_key __srcu_key; \
> @@ -56,7 +55,12 @@ int __init_srcu_struct_fast_updown(struct srcu_struct
> *ssp, const char *name,
> #define __SRCU_DEP_MAP_INIT(srcu_name) .dep_map = { .name = #srcu_name
> },
> #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
>
> -int init_srcu_struct(struct srcu_struct *ssp);
> +int init_srcu_struct_generic(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_generic(ssp);
> +}
__init_srcu_struct() invokes init_srcu_struct_generic()...
> #ifndef CONFIG_TINY_SRCU
> int init_srcu_struct_fast(struct srcu_struct *ssp);
> int init_srcu_struct_fast_updown(struct srcu_struct *ssp);
> @@ -65,6 +69,13 @@ int init_srcu_struct_fast_updown(struct srcu_struct *ssp);
> #define __SRCU_DEP_MAP_INIT(srcu_name)
> #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
>
> +#define init_srcu_struct(ssp) \
> +({ \
> + static struct lock_class_key __srcu_key; \
> + \
> + __init_srcu_struct((ssp), #ssp, &__srcu_key); \
> +})
...and here is where it moved to.
> +
> /* Values for SRCU Tree srcu_data ->srcu_reader_flavor, but also used by
> rcutorture. */
> #define SRCU_READ_FLAVOR_NORMAL 0x1 //
> srcu_read_lock().
> #define SRCU_READ_FLAVOR_NMI 0x2 //
> srcu_read_lock_nmisafe().
> diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
> index a2e2d516e51b..780a95e8cad7 100644
> --- a/kernel/rcu/srcutiny.c
> +++ b/kernel/rcu/srcutiny.c
> @@ -48,15 +48,15 @@ static int init_srcu_struct_fields(struct srcu_struct
> *ssp)
>
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
>
> -int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
> - struct lock_class_key *key)
> +int init_srcu_struct_lockdep(struct srcu_struct *ssp, const char *name,
> + struct lock_class_key *key)
> {
> /* Don't re-initialize a lock while it is held. */
> debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));
> lockdep_init_map(&ssp->dep_map, name, key, 0);
> return init_srcu_struct_fields(ssp);
> }
> -EXPORT_SYMBOL_GPL(__init_srcu_struct);
> +EXPORT_SYMBOL_GPL(init_srcu_struct_lockdep);
init_srcu_struct_lockdep() invokes init_srcu_struct_fields()...
> #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
>
> @@ -68,11 +68,11 @@ EXPORT_SYMBOL_GPL(__init_srcu_struct);
> * to any other function. Each srcu_struct represents a separate domain
> * of SRCU protection.
> */
> -int init_srcu_struct(struct srcu_struct *ssp)
> +int init_srcu_struct_generic(struct srcu_struct *ssp)
> {
> return init_srcu_struct_fields(ssp);
> }
> -EXPORT_SYMBOL_GPL(init_srcu_struct);
> +EXPORT_SYMBOL_GPL(init_srcu_struct_generic);
init_srcu_struct_generic() invokes init_srcu_struct_fields()...
> #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
>
> diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> index 0d01cd8c4b4a..45154630c54e 100644
> --- a/kernel/rcu/srcutree.c
> +++ b/kernel/rcu/srcutree.c
> @@ -266,12 +266,13 @@ __init_srcu_struct_common(struct srcu_struct *ssp,
> const char *name, struct lock
> return init_srcu_struct_fields(ssp, false);
> }
>
> -int __init_srcu_struct(struct srcu_struct *ssp, const char *name, struct
> lock_class_key *key)
> +int init_srcu_struct_lockdep(struct srcu_struct *ssp, const char *name,
> + struct lock_class_key *key)
> {
> ssp->srcu_reader_flavor = 0;
> return __init_srcu_struct_common(ssp, name, key);
> }
> -EXPORT_SYMBOL_GPL(__init_srcu_struct);
> +EXPORT_SYMBOL_GPL(init_srcu_struct_lockdep);
init_srcu_struct_lockdep() invokes __init_srcu_struct_common()...
> int __init_srcu_struct_fast(struct srcu_struct *ssp, const char *name,
> struct lock_class_key *key)
> {
> @@ -301,12 +302,12 @@ EXPORT_SYMBOL_GPL(__init_srcu_struct_fast_updown);
> * to any other function. Each srcu_struct represents a separate domain
> * of SRCU protection.
> */
> -int init_srcu_struct(struct srcu_struct *ssp)
> +int init_srcu_struct_generic(struct srcu_struct *ssp)
> {
> ssp->srcu_reader_flavor = 0;
> return init_srcu_struct_fields(ssp, false);
> }
> -EXPORT_SYMBOL_GPL(init_srcu_struct);
> +EXPORT_SYMBOL_GPL(init_srcu_struct_generic);
init_srcu_struct_generic() invokes init_srcu_struct_fields()...
This gets me the structure shown in the attached PDF. Did I get it
right?
I am surprised not to see any changes involving cleanup_srcu_struct().
What did I miss?
And again, please put the following in a later patch to allow separate
evaluation of the restructuring.
Thanx, Paul
> /**
> * init_srcu_struct_fast - initialize a fast-reader sleep-RCU structure
> 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);
> +}
> --
> 2.51.2
>
argh.pdf
Description: init_srcu_struct.pdf
