For almost 20 years, the int return value from srcu_read_lock() has
been always either zero or one. This commit therefore documents the
fact that it will be non-negative.
Signed-off-by: Paul E. McKenney <paul...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Andrii Nakryiko <and...@kernel.org
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index bab1dae3f69e6..512a8c54ba5ba 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -238,13 +238,14 @@ void srcu_check_read_flavor(struct srcu_struct *ssp, int
read_flavor);
* a mutex that is held elsewhere while calling synchronize_srcu() or
* synchronize_srcu_expedited().
*
- * 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.
+ * The return value from srcu_read_lock() is guaranteed to be
+ * non-negative. This value 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)
{
