linux-kernel - Re: [PATCH] pcmcia/cm4000: remove useless variable tmp

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Date:   Tue, 21 Jan 2020 17:53:53 +0800
From:   Alex Shi <alex.shi@...ux.alibaba.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Harald Welte <laforge@...monks.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pcmcia/cm4000: remove useless variable tmp



在 2020/1/21 下午5:08, Arnd Bergmann 写道:
> On Tue, Jan 21, 2020 at 9:50 AM Alex Shi <alex.shi@...ux.alibaba.com> wrote:
>>
>> No one care the value of 'tmp' in func cmm_write. better to remove it.
> 
> Hi Alex,
> 
>> @@ -1146,7 +1145,7 @@ static ssize_t cmm_write(struct file *filp, const char __user *buf,
>>         set_cardparameter(dev);
>>
>>         /* dummy read, reset flag procedure received */
>> -       tmp = inb(REG_FLAGS1(iobase));
>> +       inb(REG_FLAGS1(iobase));
> 
> I think this may cause warnings on some architectures, when inb() is a macro
> that just turns into a pointer dereference. You could write it as
> 
>      (void)inb(REG_FLAGS1(iobase));
> 
> which would not warn anywhere.
> 
>       Arnd
> 

Thanks a lot Arnd!


>From 9e54770c6911ae7da7d2f74774bbef019e459bc9 Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@...ux.alibaba.com>
Date: Fri, 17 Jan 2020 09:10:47 +0800
Subject: [PATCH v2] pcmcia/cm4000: remove useless variable tmp

No one care the value of 'tmp' in func cmm_write. better to remove it.

Arnd Bergmann pointed just remove may cause warning in some arch where 
inb is macro, and suggest add a cast '(void)' for this. Thanks!

Signed-off-by: Alex Shi <alex.shi@...ux.alibaba.com>
Cc: Harald Welte <laforge@...monks.org>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-kernel@...r.kernel.org
---
 drivers/char/pcmcia/cm4000_cs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c
index 15bf585af5d3..0f55bed6c71f 100644
--- a/drivers/char/pcmcia/cm4000_cs.c
+++ b/drivers/char/pcmcia/cm4000_cs.c
@@ -1048,7 +1048,6 @@ static ssize_t cmm_write(struct file *filp, const char __user *buf,
 	struct cm4000_dev *dev = filp->private_data;
 	unsigned int iobase = dev->p_dev->resource[0]->start;
 	unsigned short s;
-	unsigned char tmp;
 	unsigned char infolen;
 	unsigned char sendT0;
 	unsigned short nsend;
@@ -1146,7 +1145,7 @@ static ssize_t cmm_write(struct file *filp, const char __user *buf,
 	set_cardparameter(dev);
 
 	/* dummy read, reset flag procedure received */
-	tmp = inb(REG_FLAGS1(iobase));
+	(void)inb(REG_FLAGS1(iobase));
 
 	dev->flags1 = 0x20	/* T_Active */
 	    | (sendT0)
-- 
1.8.3.1