Building the Linux kernel with Clang and LLVM
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From: Arnd Bergmann <arnd@kernel.org>
To: "Alex Deucher" <alexander.deucher@amd.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Pan, Xinhui" <Xinhui.Pan@amd.com>,
	"David Airlie" <airlied@linux.ie>,
	"Daniel Vetter" <daniel@ffwll.ch>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Evan Quan <evan.quan@amd.com>,
	Hawking Zhang <Hawking.Zhang@amd.com>,
	Huang Rui <ray.huang@amd.com>, shaoyunl <shaoyun.liu@amd.com>,
	Andrey Grodzovsky <andrey.grodzovsky@amd.com>,
	Jack Zhang <Jack.Zhang1@amd.com>,
	amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH] drm/amdgpu: fix clang out-of-range warning
Date: Mon, 27 Sep 2021 14:19:45 +0200	[thread overview]
Message-ID: <20210927121958.941637-1-arnd@kernel.org> (raw)

From: Arnd Bergmann <arnd@arndb.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@arndb.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


             reply	other threads:[~2021-09-27 12:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-27 12:19 Arnd Bergmann [this message]
2021-09-27 12:26 ` [PATCH] drm/amdgpu: fix clang out-of-range warning Christian König
2021-09-28  9:56 ` Michel Dänzer

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