diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/revocable.h | 54 |
1 files changed, 38 insertions, 16 deletions
diff --git a/include/linux/revocable.h b/include/linux/revocable.h index d5da3584adbe..e3d6d2c953a3 100644 --- a/include/linux/revocable.h +++ b/include/linux/revocable.h @@ -10,27 +10,46 @@ #include <linux/cleanup.h> struct device; -struct revocable; struct revocable_provider; +/** + * struct revocable - A handle for resource consumer. + * @rp: The pointer of resource provider. + * @idx: The index for the RCU critical section. + */ +struct revocable { + struct revocable_provider *rp; + int idx; +}; + struct revocable_provider __rcu *revocable_provider_alloc(void *res); void revocable_provider_revoke(struct revocable_provider __rcu **rp); -struct revocable *revocable_alloc(struct revocable_provider __rcu *rp); -void revocable_free(struct revocable *rev); +int revocable_init(struct revocable_provider __rcu *rp, struct revocable *rev); +void revocable_deinit(struct revocable *rev); void *revocable_try_access(struct revocable *rev) __acquires(&rev->rp->srcu); void revocable_withdraw_access(struct revocable *rev) __releases(&rev->rp->srcu); -DEFINE_FREE(access_rev, struct revocable *, if (_T) revocable_withdraw_access(_T)) +DEFINE_FREE(access_rev, struct revocable *, { + if ((_T)->idx != -1) + revocable_withdraw_access(_T); + if ((_T)->rp) + revocable_deinit(_T); +}) + +#define _REVOCABLE_TRY_ACCESS_WITH(_rp, _rev, _res) \ + struct revocable _rev = {.rp = NULL, .idx = -1}; \ + struct revocable *__UNIQUE_ID(name) __free(access_rev) = &_rev; \ + _res = revocable_init(_rp, &_rev) ? NULL : revocable_try_access(&_rev) /** * REVOCABLE_TRY_ACCESS_WITH() - A helper for accessing revocable resource - * @_rev: The consumer's ``struct revocable *`` handle. + * @_rp: The provider's ``struct revocable_provider *`` handle. * @_res: A pointer variable that will be assigned the resource. * * The macro simplifies the access-release cycle for consumers, ensuring that - * revocable_withdraw_access() is always called, even in the case of an early - * exit. + * corresponding revocable_withdraw_access() and revocable_deinit() are called, + * even in the case of an early exit. * * It creates a local variable in the current scope. @_res is populated with * the result of revocable_try_access(). The consumer code **must** check if @@ -41,13 +60,15 @@ DEFINE_FREE(access_rev, struct revocable *, if (_T) revocable_withdraw_access(_T * are allowed before the helper. Otherwise, the compiler fails with * "jump bypasses initialization of variable with __attribute__((cleanup))". */ -#define REVOCABLE_TRY_ACCESS_WITH(_rev, _res) \ - struct revocable *__UNIQUE_ID(name) __free(access_rev) = _rev; \ - _res = revocable_try_access(_rev) +#define REVOCABLE_TRY_ACCESS_WITH(_rp, _res) \ + _REVOCABLE_TRY_ACCESS_WITH(_rp, __UNIQUE_ID(name), _res) -#define _REVOCABLE_TRY_ACCESS_SCOPED(_rev, _label, _res) \ - for (struct revocable *__UNIQUE_ID(name) __free(access_rev) = _rev; \ - (_res = revocable_try_access(_rev)) || true; ({ goto _label; })) \ +#define _REVOCABLE_TRY_ACCESS_SCOPED(_rp, _rev, _label, _res) \ + for (struct revocable _rev = {.rp = NULL, .idx = -1}, \ + *__UNIQUE_ID(name) __free(access_rev) = &_rev; \ + (_res = revocable_init(_rp, &_rev) ? NULL : \ + revocable_try_access(&_rev)) || true; \ + ({ goto _label; })) \ if (0) { \ _label: \ break; \ @@ -55,13 +76,14 @@ _label: \ /** * REVOCABLE_TRY_ACCESS_SCOPED() - A helper for accessing revocable resource - * @_rev: The consumer's ``struct revocable *`` handle. + * @_rp: The provider's ``struct revocable_provider *`` handle. * @_res: A pointer variable that will be assigned the resource. * * Similar to REVOCABLE_TRY_ACCESS_WITH() but with an explicit scope from a * temporary ``for`` loop. */ -#define REVOCABLE_TRY_ACCESS_SCOPED(_rev, _res) \ - _REVOCABLE_TRY_ACCESS_SCOPED(_rev, __UNIQUE_ID(label), _res) +#define REVOCABLE_TRY_ACCESS_SCOPED(_rp, _res) \ + _REVOCABLE_TRY_ACCESS_SCOPED(_rp, __UNIQUE_ID(name), \ + __UNIQUE_ID(label), _res) #endif /* __LINUX_REVOCABLE_H */ |