linux-kernel - [PATCH next] drm/loongson: Fix error handling in lsdc_pixel_pll

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Date:   Thu, 20 Jul 2023 05:39:50 -0700
From:   Harshit Mogalapalli <harshit.m.mogalapalli@...cle.com>
To:     Sui Jingfeng <suijingfeng@...ngson.cn>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:     dan.carpenter@...aro.org, kernel-janitors@...r.kernel.org,
        error27@...il.com, harshit.m.mogalapalli@...cle.com
Subject: [PATCH next] drm/loongson: Fix error handling in lsdc_pixel_pll_setup()

There are two problems in lsdc_pixel_pll_setup()
1. If kzalloc() fails then call iounmap() to release the resources.
2. Both kzalloc and ioremap doesnot return error pointers on failure, so
   using IS_ERR_OR_NULL() checks is a bit confusing and not very right,
   fix this by changing those to NULL checks instead.

Fixes: f39db26c5428 ("drm: Add kms driver for loongson display controller")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@...cle.com>
---
This is found with static analysis with smacth and only compile tested.
---
 drivers/gpu/drm/loongson/lsdc_pixpll.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/loongson/lsdc_pixpll.c b/drivers/gpu/drm/loongson/lsdc_pixpll.c
index 04c15b4697e2..2609a2256da4 100644
--- a/drivers/gpu/drm/loongson/lsdc_pixpll.c
+++ b/drivers/gpu/drm/loongson/lsdc_pixpll.c
@@ -120,12 +120,14 @@ static int lsdc_pixel_pll_setup(struct lsdc_pixpll * const this)
 	struct lsdc_pixpll_parms *pparms;
 
 	this->mmio = ioremap(this->reg_base, this->reg_size);
-	if (IS_ERR_OR_NULL(this->mmio))
+	if (!this->mmio)
 		return -ENOMEM;
 
 	pparms = kzalloc(sizeof(*pparms), GFP_KERNEL);
-	if (IS_ERR_OR_NULL(pparms))
+	if (!pparms) {
+		iounmap(this->mmio);
 		return -ENOMEM;
+	}
 
 	pparms->ref_clock = LSDC_PLL_REF_CLK_KHZ;
 
-- 
2.39.3