[PATCH] SRCU: report out-of-memory errors (e6a92013) · Commits · 戴 / test

Currently the init_srcu_struct() routine has no way to report out-of-memory errors. This patch (as761) makes it return -ENOMEM when the per-cpu data allocation fails. The patch also makes srcu_init_notifier_head() report a BUG if a notifier head can't be initialized. Perhaps it should return -ENOMEM instead, but in the most likely cases where this might occur I don't think any recovery is possible. Notifier chains generally are not created dynamically. [akpm@osdl.org: avoid statement-with-side-effect in macro] Signed-off-by:

Alan Stern <stern@rowland.harvard.edu> Acked-by:

Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

include/linux/srcu.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -43,7 +43,7 @@ struct srcu_struct {
		#define srcu_barrier()
		#endif /* #else #ifndef CONFIG_PREEMPT */

		void init_srcu_struct(struct srcu_struct *sp);
		int init_srcu_struct(struct srcu_struct *sp);
		void cleanup_srcu_struct(struct srcu_struct *sp);
		int srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
		void srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);

kernel/srcu.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -42,11 +42,12 @@
		* to any other function. Each srcu_struct represents a separate domain
		* of SRCU protection.
		*/
		void init_srcu_struct(struct srcu_struct *sp)
		int init_srcu_struct(struct srcu_struct *sp)
		{
		sp->completed = 0;
		sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array);
		mutex_init(&sp->mutex);
		sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array);
		return (sp->per_cpu_ref ? 0 : -ENOMEM);
		}

		/*

kernel/sys.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -517,7 +517,8 @@ EXPORT_SYMBOL_GPL(srcu_notifier_call_chain);
		void srcu_init_notifier_head(struct srcu_notifier_head *nh)
		{
		mutex_init(&nh->mutex);
		init_srcu_struct(&nh->srcu);
		if (init_srcu_struct(&nh->srcu) < 0)
		BUG();
		nh->head = NULL;
		}

Admin message