linux-kernel - [PATCH] drm/amd/display: Remove pointless NULL checks in dmub_psr_copy

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Date:   Mon,  2 Mar 2020 15:42:17 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Harry Wentland <harry.wentland@....com>,
        Leo Li <sunpeng.li@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "David (ChunMing) Zhou" <David1.Zhou@....com>
Cc:     amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH] drm/amd/display: Remove pointless NULL checks in dmub_psr_copy_settings

Clang warns:

drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:147:31: warning:
address of 'pipe_ctx->plane_res' will always evaluate to 'true'
[-Wpointer-bool-conversion]
        if (!pipe_ctx || !&pipe_ctx->plane_res || !&pipe_ctx->stream_res)
                         ~ ~~~~~~~~~~^~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:147:56: warning:
address of 'pipe_ctx->stream_res' will always evaluate to 'true'
[-Wpointer-bool-conversion]
        if (!pipe_ctx || !&pipe_ctx->plane_res || !&pipe_ctx->stream_res)
                                                  ~ ~~~~~~~~~~^~~~~~~~~~
2 warnings generated.

As long as pipe_ctx is not NULL, the address of members in this struct
cannot be NULL, which means these checks will always evaluate to false.

Fixes: 4c1a1335dfe0 ("drm/amd/display: Driverside changes to support PSR in DMCUB")
Link: https://github.com/ClangBuiltLinux/linux/issues/915
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c b/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
index 2c932c29f1f9..a9e1c01e9d9b 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
@@ -144,7 +144,7 @@ static bool dmub_psr_copy_settings(struct dmub_psr *dmub,
 		}
 	}
 
-	if (!pipe_ctx || !&pipe_ctx->plane_res || !&pipe_ctx->stream_res)
+	if (!pipe_ctx)
 		return false;
 
 	// First, set the psr version
-- 
2.25.1