ipc_service: static_vrings: Fix buffer sizing

carlocaione · carlescufi · commit 6ae34c9176a4 · 2023-08-29T10:26:59.000+02:00
We are returning an off-by-one number of buffers in some circumstances,
fix the calculation.

Signed-off-by: Carlo Caione &lt;ccaione@baylibre.com&gt;
diff --git a/subsys/ipc/ipc_service/backends/ipc_rpmsg_static_vrings.h b/subsys/ipc/ipc_service/backends/ipc_rpmsg_static_vrings.h
@@ -163,5 +163,5 @@ static inline unsigned int optimal_num_desc(size_t mem_size, unsigned int buf_si
 		num_desc++;
 	}
 
-	return (1 << (find_msb_set(num_desc) - 1));
+	return (1 << (find_msb_set(--num_desc) - 1));
 }

Original file line number	Diff line number	Diff line change
`@@ -163,5 +163,5 @@ static inline unsigned int optimal_num_desc(size_t mem_size, unsigned int buf_si`
`163`	`163`	`num_desc++;`
`164`	`164`	`}`
`165`	`165`
`166`		`- return (1 << (find_msb_set(num_desc) - 1));`
	`166`	`+ return (1 << (find_msb_set(--num_desc) - 1));`
`167`	`167`	`}`