linux-kernel - [PATCH v2] x86/boot/KASLR: Fix unused variable warning

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Message-Id: <20200103033929.4956-1-zhenzhong.duan@gmail.com>
Date:   Fri,  3 Jan 2020 11:39:29 +0800
From:   Zhenzhong Duan <zhenzhong.duan@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     x86@...nel.org, Zhenzhong Duan <zhenzhong.duan@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...e.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Chao Fan <fanc.fnst@...fujitsu.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH v2] x86/boot/KASLR: Fix unused variable warning

Local variable 'i' is referenced only when CONFIG_MEMORY_HOTREMOVE and
CONFIG_ACPI are defined, but definition of variable 'i' is out of guard.
If any of the two macros is undefined, below warning triggers during
build, fix it by moving 'i' in the guard.

arch/x86/boot/compressed/kaslr.c:698:6: warning: unused variable ‘i’ [-Wunused-variable]

Also use true/false instead of 1/0 for boolean return.

Fixes: 690eaa532057 ("x86/boot/KASLR: Limit KASLR to extract the kernel in immovable memory only")
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Chao Fan <fanc.fnst@...fujitsu.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
---
v2: update description per Boris.

 arch/x86/boot/compressed/kaslr.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index d7408af55738..fff24a55bfd5 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -695,7 +695,6 @@ static bool process_mem_region(struct mem_vector *region,
 			       unsigned long long minimum,
 			       unsigned long long image_size)
 {
-	int i;
 	/*
 	 * If no immovable memory found, or MEMORY_HOTREMOVE disabled,
 	 * use @region directly.
@@ -705,12 +704,13 @@ static bool process_mem_region(struct mem_vector *region,
 
 		if (slot_area_index == MAX_SLOT_AREA) {
 			debug_putstr("Aborted e820/efi memmap scan (slot_areas full)!\n");
-			return 1;
+			return true;
 		}
-		return 0;
+		return false;
 	}
 
 #if defined(CONFIG_MEMORY_HOTREMOVE) && defined(CONFIG_ACPI)
+	int i;
 	/*
 	 * If immovable memory found, filter the intersection between
 	 * immovable memory and @region.
@@ -734,11 +734,11 @@ static bool process_mem_region(struct mem_vector *region,
 
 		if (slot_area_index == MAX_SLOT_AREA) {
 			debug_putstr("Aborted e820/efi memmap scan when walking immovable regions(slot_areas full)!\n");
-			return 1;
+			return true;
 		}
 	}
 #endif
-	return 0;
+	return false;
 }
 
 #ifdef CONFIG_EFI
-- 
2.17.1