linux-kernel - [PATCH] drm/msm/dp: Drop unnecessary NULL checks after container

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Date:   Mon, 24 May 2021 20:20:33 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Rob Clark <robdclark@...il.com>
Cc:     Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH] drm/msm/dp: Drop unnecessary NULL checks after container_of

The result of container_of() operations is never NULL unless the embedded
element is the first element of the structure. This is not the case here.
The NULL check on the result of container_of() is therefore unnecessary
and misleading. Remove it.

This change was made automatically with the following Coccinelle script.

@@
type t;
identifier v;
statement s;
@@

<+...
(
  t v = container_of(...);
|
  v = container_of(...);
)
  ...
  when != v
- if (\( !v \| v == NULL \) ) s
...+>

While at it, remove unused but assigned variable hpd in
dp_display_usbpd_attention_cb().

Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 25 -------------------------
 1 file changed, 25 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 1784e119269b..a74e7ef96fcf 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -208,10 +208,6 @@ static int dp_display_bind(struct device *dev, struct device *master,
 
 	dp = container_of(g_dp_display,
 			struct dp_display_private, dp_display);
-	if (!dp) {
-		DRM_ERROR("DP driver bind failed. Invalid driver data\n");
-		return -EINVAL;
-	}
 
 	dp->dp_display.drm_dev = drm;
 	priv = drm->dev_private;
@@ -252,10 +248,6 @@ static void dp_display_unbind(struct device *dev, struct device *master,
 
 	dp = container_of(g_dp_display,
 			struct dp_display_private, dp_display);
-	if (!dp) {
-		DRM_ERROR("Invalid DP driver data\n");
-		return;
-	}
 
 	dp_power_client_deinit(dp->power);
 	dp_aux_unregister(dp->aux);
@@ -406,11 +398,6 @@ static int dp_display_usbpd_configure_cb(struct device *dev)
 
 	dp = container_of(g_dp_display,
 			struct dp_display_private, dp_display);
-	if (!dp) {
-		DRM_ERROR("no driver data found\n");
-		rc = -ENODEV;
-		goto end;
-	}
 
 	dp_display_host_init(dp, false);
 
@@ -437,11 +424,6 @@ static int dp_display_usbpd_disconnect_cb(struct device *dev)
 
 	dp = container_of(g_dp_display,
 			struct dp_display_private, dp_display);
-	if (!dp) {
-		DRM_ERROR("no driver data found\n");
-		rc = -ENODEV;
-		return rc;
-	}
 
 	dp_add_event(dp, EV_USER_NOTIFICATION, false, 0);
 
@@ -502,7 +484,6 @@ static int dp_display_usbpd_attention_cb(struct device *dev)
 	int rc = 0;
 	u32 sink_request;
 	struct dp_display_private *dp;
-	struct dp_usbpd *hpd;
 
 	if (!dev) {
 		DRM_ERROR("invalid dev\n");
@@ -511,12 +492,6 @@ static int dp_display_usbpd_attention_cb(struct device *dev)
 
 	dp = container_of(g_dp_display,
 			struct dp_display_private, dp_display);
-	if (!dp) {
-		DRM_ERROR("no driver data found\n");
-		return -ENODEV;
-	}
-
-	hpd = dp->usbpd;
 
 	/* check for any test request issued by sink */
 	rc = dp_link_process_request(dp->link);
-- 
2.25.1