linux-kernel - [PATCH] make dt_scan_depth1

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Date:	Mon, 25 Apr 2016 11:25:11 +0100 (BST)
From:	Stefano Stabellini <sstabellini@...nel.org>
To:	linux-arm-kernel@...ts.infradead.org
cc:	sstabellini@...nel.org, mark.rutland@....com,
	catalin.marinas@....com, will.deacon@....com,
	shannon.zhao@...aro.org, linux-kernel@...r.kernel.org,
	peter.huangpeng@...wei.com
Subject: [PATCH] make dt_scan_depth1_nodes more readable

From: Mark Rutland <mark.rutland@....com>

Improve the readability of dt_scan_depth1_nodes by removing the nested
conditionals.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Signed-off-by: Stefano Stabellini <sstabellini@...nel.org>

---

Note: this patch is based on xentip/for-linus-4.7

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 57ee317..6884c76 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -66,17 +66,24 @@ static int __init dt_scan_depth1_nodes(unsigned long node,
 				       void *data)
 {
 	/*
-	 * Return 1 as soon as we encounter a node at depth 1 that is
-	 * not the /chosen node, or /hypervisor node with compatible
-	 * string "xen,xen".
+	 * Ignore anything not directly under the root node; we'll
+	 * catch its parent instead.
 	 */
-	if (depth == 1 && (strcmp(uname, "chosen") != 0)) {
-		if (strcmp(uname, "hypervisor") != 0 ||
-		    !of_flat_dt_is_compatible(node, "xen,xen"))
-			return 1;
-	}
+	if (depth != 1)
+		return 0;
 
-	return 0;
+	if (strcmp(uname, "chosen") == 0)
+		return 0;
+
+	if (strcmp(uname, "hypervisor") == 0 &&
+	    of_flat_dt_is_compatible(node, "xen,xen"))
+		return 0;
+
+	/*
+	 * This node at depth 1 is neither a chosen node nor a xen node,
+	 * which we do not expect.
+	 */
+	return 1;
 }
 
 /*