linux-kernel - [PATCH] drm/amdgpu: fix clang out-of-range warning

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Message-Id: <20210927121958.941637-1-arnd@kernel.org>
Date:   Mon, 27 Sep 2021 14:19:45 +0200
From:   Arnd Bergmann <arnd@...nel.org>
To:     Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Evan Quan <evan.quan@....com>,
        Hawking Zhang <Hawking.Zhang@....com>,
        Huang Rui <ray.huang@....com>, shaoyunl <shaoyun.liu@....com>,
        Andrey Grodzovsky <andrey.grodzovsky@....com>,
        Jack Zhang <Jack.Zhang1@....com>,
        amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, llvm@...ts.linux.dev
Subject: [PATCH] drm/amdgpu: fix clang out-of-range warning

From: Arnd Bergmann <arnd@...db.de>

clang-14 points out that comparing an 'unsigned int' against a large
64-bit constantn is pointless:

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:1206:18: error: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
                    res->start > 0x100000000ull)

Rephrase the comparison using the upper_32_bits() macro, which should
keep it legible while avoiding the warning.

Fixes: 31b8adab3247 ("drm/amdgpu: require a root bus window above 4GB for BAR resize")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index ab3794c42d36..741a55031ca1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1203,7 +1203,7 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
 
 	pci_bus_for_each_resource(root, res, i) {
 		if (res && res->flags & (IORESOURCE_MEM | IORESOURCE_MEM_64) &&
-		    res->start > 0x100000000ull)
+		    upper_32_bits(res->start) != 0)
 			break;
 	}
 
-- 
2.29.2