linux-kernel - [PATCH] dma: dmatest: Use div64

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Message-Id: <20230814062246.4636-1-coolrrsh@gmail.com>
Date:   Mon, 14 Aug 2023 11:52:46 +0530
From:   coolrrsh@...il.com
To:     vkoul@...nel.org, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     linux-kernel-mentees@...ts.linuxfoundation.org,
        Rajeshwar R Shinde <coolrrsh@...il.com>
Subject: [PATCH] dma: dmatest: Use div64_s64

From: Rajeshwar R Shinde <coolrrsh@...il.com>

In the function do_div, the dividend is evaluated multiple times
so it can cause side effects. Therefore replace it with div64_s64.

This fixes warning such as:
drivers/dma/dmatest.c:496:1-7:
WARNING: do_div() does a 64-by-32 division,
please consider using div64_s64 instead.

Signed-off-by: Rajeshwar R Shinde <coolrrsh@...il.com>
---
 drivers/dma/dmatest.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index ffe621695e47..07042f239db8 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -9,6 +9,7 @@
 
 #include <linux/err.h>
 #include <linux/delay.h>
+#include <linux/math64.h>
 #include <linux/dma-mapping.h>
 #include <linux/dmaengine.h>
 #include <linux/freezer.h>
@@ -493,7 +494,7 @@ static unsigned long long dmatest_persec(s64 runtime, unsigned int val)
 
 	per_sec *= val;
 	per_sec = INT_TO_FIXPT(per_sec);
-	do_div(per_sec, runtime);
+	per_sec=div64_s64(per_sec, runtime);
 
 	return per_sec;
 }
-- 
2.25.1