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| author | Paul E. McKenney <paulmck@kernel.org> | 2024-10-15 09:11:03 -0700 |
|---|---|---|
| committer | Frederic Weisbecker <frederic@kernel.org> | 2024-11-12 15:43:06 +0100 |
| commit | c071b8e5351453c2cb2d12f425d928f3a24ed2d3 (patch) | |
| tree | 9a288a0a68b873fc2084fd7d7cfbfdd212de3023 | |
| parent | 9a87bda2b6881de10fb5791cade3719663b8d660 (diff) | |
srcu: Improve srcu_read_lock{,_nmisafe}() comments
This commit adds some additional usage constraints to the kernel-doc
headers of srcu_read_lock() and srcu_read_lock_nmi_safe().
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
| -rw-r--r-- | include/linux/srcu.h | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 06728ef6f32a..46fd06b212ba 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -235,10 +235,13 @@ static inline void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flav * a mutex that is held elsewhere while calling synchronize_srcu() or * synchronize_srcu_expedited(). * - * Note that srcu_read_lock() and the matching srcu_read_unlock() must - * occur in the same context, for example, it is illegal to invoke - * srcu_read_unlock() in an irq handler if the matching srcu_read_lock() - * was invoked in process context. + * The return value from srcu_read_lock() must be passed unaltered + * to the matching srcu_read_unlock(). Note that srcu_read_lock() and + * the matching srcu_read_unlock() must occur in the same context, for + * example, it is illegal to invoke srcu_read_unlock() in an irq handler + * if the matching srcu_read_lock() was invoked in process context. Or, + * for that matter to invoke srcu_read_unlock() from one task and the + * matching srcu_read_lock() from another. */ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp) { @@ -256,6 +259,10 @@ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp) * * Enter an SRCU read-side critical section, but in an NMI-safe manner. * See srcu_read_lock() for more information. + * + * If srcu_read_lock_nmisafe() is ever used on an srcu_struct structure, + * then none of the other flavors may be used, whether before, during, + * or after. */ static inline int srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp) { |