linux-kernel - Re: [PATCH 4/8]drivers:tmp.c Fix warning: variable 'rc' set but not used

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Message-ID: <4C17D646.5030306@gmail.com>
Date:	Tue, 15 Jun 2010 12:36:38 -0700
From:	"Justin P. Mattock" <justinmattock@...il.com>
To:	"Sergey V." <sftp.mtuci@...il.com>
CC:	linux-kernel@...r.kernel.org, reiserfs-devel@...r.kernel.org,
	linux-bluetooth@...r.kernel.org, clemens@...isch.de,
	debora@...ux.vnet.ibm.com, dri-devel@...ts.freedesktop.org,
	linux-i2c@...r.kernel.org, linux1394-devel@...ts.sourceforge.net,
	linux-media@...r.kernel.org
Subject: Re: [PATCH 4/8]drivers:tmp.c Fix warning: variable 'rc' set but not
 used

On 06/15/2010 11:53 AM, Sergey V. wrote:
> On Tuesday 15 of June 2010 00:26:44 Justin P. Mattock wrote:
>> Im getting this warning when compiling:
>>   CC      drivers/char/tpm/tpm.o
>> drivers/char/tpm/tpm.c: In function 'tpm_gen_interrupt':
>> drivers/char/tpm/tpm.c:508:10: warning: variable 'rc' set but not used
>>
>> The below patch gets rid of the warning,
>> but I'm not sure if it's the best solution.
>>
>>   Signed-off-by: Justin P. Mattock<justinmattock@...il.com>
>>
>> ---
>>   drivers/char/tpm/tpm.c |    2 ++
>>   1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
>> index 05ad4a1..3d685dc 100644
>> --- a/drivers/char/tpm/tpm.c
>> +++ b/drivers/char/tpm/tpm.c
>> @@ -514,6 +514,8 @@ void tpm_gen_interrupt(struct tpm_chip *chip)
>>
>>   	rc = transmit_cmd(chip,&tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
>>   			"attempting to determine the timeouts");
>> +	if (!rc)
>> +		rc = 0;
>>   }
>>   EXPORT_SYMBOL_GPL(tpm_gen_interrupt);
>>
>> --
>> 1.7.1.rc1.21.gf3bd6
>>
>
> Hi Justin
>
> IMHO
> See code of functions tpm_transmit(), transmit_cmd and tpm_gen_interrupt().
> In tpm_gen_interrupt() not need check rc for wrong value bacause if in function
> transmit_cmd() len == TPM_ERROR_SIZE then put a debug message (dev_dbg()).
> Again, if something wrong in tpm_transmit() then runs dev_err() and rc in
> tpm_gen_interrupt() get -E* value.
> So, we can remove unused rc variable in tpm_gen_interrupt().
>
> See patch below. Note: I not tested it.
>
>
> Subject: [PATCH] drivers: tpm.c: Remove unused variable 'rc'
>
> ---
>   drivers/char/tpm/tpm.c |    5 ++---
>   1 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
> index 05ad4a1..f9f5b47 100644
> --- a/drivers/char/tpm/tpm.c
> +++ b/drivers/char/tpm/tpm.c
> @@ -505,15 +505,14 @@ ssize_t tpm_getcap(struct device *dev, __be32 subcap_id,
> cap_t *cap,
>   void tpm_gen_interrupt(struct tpm_chip *chip)
>   {
>   	struct	tpm_cmd_t tpm_cmd;
> -	ssize_t rc;
>
>   	tpm_cmd.header.in = tpm_getcap_header;
>   	tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
>   	tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
>   	tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT;
>
> -	rc = transmit_cmd(chip,&tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
> -			"attempting to determine the timeouts");
> +	transmit_cmd(chip,&tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
> +		     "attempting to determine the timeouts");
>   }
>   EXPORT_SYMBOL_GPL(tpm_gen_interrupt);
>



o.k. applied this patch and rebuilt, here is what I see:

   CC [M]  drivers/char/ipmi/ipmi_poweroff.o
   CC      drivers/char/tpm/tpm.o
   CC      drivers/char/tpm/tpm_bios.o
   CC      drivers/char/tpm/tpm_tis.o
   LD      drivers/char/tpm/built-in.o


looks good over here Thanks for sending this..

Justin P. Mattock
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