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* [PATCH] test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx
@ 2020-04-15  0:25 Scott Branden
  2020-04-15  3:10 ` Kees Cook
  0 siblings, 1 reply; 5+ messages in thread
From: Scott Branden @ 2020-04-15  0:25 UTC (permalink / raw)
  To: Luis Chamberlain, Greg Kroah-Hartman, David Brown,
	Alexander Viro, Shuah Khan, bjorn.andersson, Shuah Khan,
	Arnd Bergmann
  Cc: Rafael J . Wysocki, linux-kernel, linux-arm-msm, linux-fsdevel,
	BCM Kernel Feedback, Olof Johansson, Andrew Morton,
	Dan Carpenter, Colin Ian King, Kees Cook, Takashi Iwai,
	linux-kselftest, Andy Gross, Scott Branden

Remove unnecessary use of test_fw_mutex in test_dev_config_show_xxx
functions that show simple bool, int, and u8.

Signed-off-by: Scott Branden <scott.branden@broadcom.com>
---
 lib/test_firmware.c | 26 +++-----------------------
 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/lib/test_firmware.c b/lib/test_firmware.c
index 0c7fbcf07ac5..9fee2b93a8d1 100644
--- a/lib/test_firmware.c
+++ b/lib/test_firmware.c
@@ -310,27 +310,13 @@ static int test_dev_config_update_bool(const char *buf, size_t size,
 	return ret;
 }
 
-static ssize_t
-test_dev_config_show_bool(char *buf,
-			  bool config)
+static ssize_t test_dev_config_show_bool(char *buf, bool val)
 {
-	bool val;
-
-	mutex_lock(&test_fw_mutex);
-	val = config;
-	mutex_unlock(&test_fw_mutex);
-
 	return snprintf(buf, PAGE_SIZE, "%d\n", val);
 }
 
-static ssize_t test_dev_config_show_int(char *buf, int cfg)
+static ssize_t test_dev_config_show_int(char *buf, int val)
 {
-	int val;
-
-	mutex_lock(&test_fw_mutex);
-	val = cfg;
-	mutex_unlock(&test_fw_mutex);
-
 	return snprintf(buf, PAGE_SIZE, "%d\n", val);
 }
 
@@ -354,14 +340,8 @@ static int test_dev_config_update_u8(const char *buf, size_t size, u8 *cfg)
 	return size;
 }
 
-static ssize_t test_dev_config_show_u8(char *buf, u8 cfg)
+static ssize_t test_dev_config_show_u8(char *buf, u8 val)
 {
-	u8 val;
-
-	mutex_lock(&test_fw_mutex);
-	val = cfg;
-	mutex_unlock(&test_fw_mutex);
-
 	return snprintf(buf, PAGE_SIZE, "%u\n", val);
 }
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx
  2020-04-15  0:25 [PATCH] test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx Scott Branden
@ 2020-04-15  3:10 ` Kees Cook
  2020-04-15 16:28   ` Scott Branden
  0 siblings, 1 reply; 5+ messages in thread
From: Kees Cook @ 2020-04-15  3:10 UTC (permalink / raw)
  To: Scott Branden
  Cc: Luis Chamberlain, Greg Kroah-Hartman, David Brown,
	Alexander Viro, Shuah Khan, bjorn.andersson, Shuah Khan,
	Arnd Bergmann, Rafael J . Wysocki, linux-kernel, linux-arm-msm,
	linux-fsdevel, BCM Kernel Feedback, Olof Johansson,
	Andrew Morton, Dan Carpenter, Colin Ian King, Takashi Iwai,
	linux-kselftest, Andy Gross

On Tue, Apr 14, 2020 at 05:25:17PM -0700, Scott Branden wrote:
> Remove unnecessary use of test_fw_mutex in test_dev_config_show_xxx
> functions that show simple bool, int, and u8.

I would expect at least a READ_ONCE(), yes?

> 
> Signed-off-by: Scott Branden <scott.branden@broadcom.com>
> ---
>  lib/test_firmware.c | 26 +++-----------------------
>  1 file changed, 3 insertions(+), 23 deletions(-)
> 
> diff --git a/lib/test_firmware.c b/lib/test_firmware.c
> index 0c7fbcf07ac5..9fee2b93a8d1 100644
> --- a/lib/test_firmware.c
> +++ b/lib/test_firmware.c
> @@ -310,27 +310,13 @@ static int test_dev_config_update_bool(const char *buf, size_t size,
>  	return ret;
>  }
>  
> -static ssize_t
> -test_dev_config_show_bool(char *buf,
> -			  bool config)
> +static ssize_t test_dev_config_show_bool(char *buf, bool val)
>  {
> -	bool val;
> -
> -	mutex_lock(&test_fw_mutex);
> -	val = config;
> -	mutex_unlock(&test_fw_mutex);
> -
>  	return snprintf(buf, PAGE_SIZE, "%d\n", val);
>  }
>  
> -static ssize_t test_dev_config_show_int(char *buf, int cfg)
> +static ssize_t test_dev_config_show_int(char *buf, int val)
>  {
> -	int val;
> -
> -	mutex_lock(&test_fw_mutex);
> -	val = cfg;
> -	mutex_unlock(&test_fw_mutex);
> -
>  	return snprintf(buf, PAGE_SIZE, "%d\n", val);
>  }
>  
> @@ -354,14 +340,8 @@ static int test_dev_config_update_u8(const char *buf, size_t size, u8 *cfg)
>  	return size;
>  }
>  
> -static ssize_t test_dev_config_show_u8(char *buf, u8 cfg)
> +static ssize_t test_dev_config_show_u8(char *buf, u8 val)
>  {
> -	u8 val;
> -
> -	mutex_lock(&test_fw_mutex);
> -	val = cfg;
> -	mutex_unlock(&test_fw_mutex);
> -
>  	return snprintf(buf, PAGE_SIZE, "%u\n", val);
>  }
>  
> -- 
> 2.17.1
> 

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx
  2020-04-15  3:10 ` Kees Cook
@ 2020-04-15 16:28   ` Scott Branden
  2020-04-15 16:44     ` Kees Cook
  0 siblings, 1 reply; 5+ messages in thread
From: Scott Branden @ 2020-04-15 16:28 UTC (permalink / raw)
  To: Kees Cook
  Cc: Luis Chamberlain, Greg Kroah-Hartman, David Brown,
	Alexander Viro, Shuah Khan, bjorn.andersson, Shuah Khan,
	Arnd Bergmann, Rafael J . Wysocki, linux-kernel, linux-arm-msm,
	linux-fsdevel, BCM Kernel Feedback, Olof Johansson,
	Andrew Morton, Dan Carpenter, Colin Ian King, Takashi Iwai,
	linux-kselftest, Andy Gross

Hi Kees,

On 2020-04-14 8:10 p.m., Kees Cook wrote:
> On Tue, Apr 14, 2020 at 05:25:17PM -0700, Scott Branden wrote:
>> Remove unnecessary use of test_fw_mutex in test_dev_config_show_xxx
>> functions that show simple bool, int, and u8.
> I would expect at least a READ_ONCE(), yes?
I don't understand why you need a READ_ONCE when removing a mutex around 
an assignment
of a parameter passed into a function being assigned to a local variable.

Could you please explain your expectations.
>
>> Signed-off-by: Scott Branden <scott.branden@broadcom.com>
>> ---
>>   lib/test_firmware.c | 26 +++-----------------------
>>   1 file changed, 3 insertions(+), 23 deletions(-)
>>
>> diff --git a/lib/test_firmware.c b/lib/test_firmware.c
>> index 0c7fbcf07ac5..9fee2b93a8d1 100644
>> --- a/lib/test_firmware.c
>> +++ b/lib/test_firmware.c
>> @@ -310,27 +310,13 @@ static int test_dev_config_update_bool(const char *buf, size_t size,
>>   	return ret;
>>   }
>>   
>> -static ssize_t
>> -test_dev_config_show_bool(char *buf,
>> -			  bool config)
>> +static ssize_t test_dev_config_show_bool(char *buf, bool val)
>>   {
>> -	bool val;
>> -
>> -	mutex_lock(&test_fw_mutex);
>> -	val = config;
>> -	mutex_unlock(&test_fw_mutex);
>> -
>>   	return snprintf(buf, PAGE_SIZE, "%d\n", val);
>>   }
>>   
>> -static ssize_t test_dev_config_show_int(char *buf, int cfg)
>> +static ssize_t test_dev_config_show_int(char *buf, int val)
>>   {
>> -	int val;
>> -
>> -	mutex_lock(&test_fw_mutex);
>> -	val = cfg;
>> -	mutex_unlock(&test_fw_mutex);
>> -
>>   	return snprintf(buf, PAGE_SIZE, "%d\n", val);
>>   }
>>   
>> @@ -354,14 +340,8 @@ static int test_dev_config_update_u8(const char *buf, size_t size, u8 *cfg)
>>   	return size;
>>   }
>>   
>> -static ssize_t test_dev_config_show_u8(char *buf, u8 cfg)
>> +static ssize_t test_dev_config_show_u8(char *buf, u8 val)
>>   {
>> -	u8 val;
>> -
>> -	mutex_lock(&test_fw_mutex);
>> -	val = cfg;
>> -	mutex_unlock(&test_fw_mutex);
>> -
>>   	return snprintf(buf, PAGE_SIZE, "%u\n", val);
>>   }
>>   
>> -- 
>> 2.17.1
>>


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx
  2020-04-15 16:28   ` Scott Branden
@ 2020-04-15 16:44     ` Kees Cook
  2020-04-16  6:00       ` Luis Chamberlain
  0 siblings, 1 reply; 5+ messages in thread
From: Kees Cook @ 2020-04-15 16:44 UTC (permalink / raw)
  To: Scott Branden
  Cc: Luis Chamberlain, Greg Kroah-Hartman, David Brown,
	Alexander Viro, Shuah Khan, bjorn.andersson, Shuah Khan,
	Arnd Bergmann, Rafael J . Wysocki, linux-kernel, linux-arm-msm,
	linux-fsdevel, BCM Kernel Feedback, Olof Johansson,
	Andrew Morton, Dan Carpenter, Colin Ian King, Takashi Iwai,
	linux-kselftest, Andy Gross

On Wed, Apr 15, 2020 at 09:28:18AM -0700, Scott Branden wrote:
> Hi Kees,
> 
> On 2020-04-14 8:10 p.m., Kees Cook wrote:
> > On Tue, Apr 14, 2020 at 05:25:17PM -0700, Scott Branden wrote:
> > > Remove unnecessary use of test_fw_mutex in test_dev_config_show_xxx
> > > functions that show simple bool, int, and u8.
> > I would expect at least a READ_ONCE(), yes?
> I don't understand why you need a READ_ONCE when removing a mutex around an
> assignment
> of a parameter passed into a function being assigned to a local variable.
> 
> Could you please explain your expectations.

Oops, yes, you're right. I misread and was thinking this was reading
from a global. This looks fine.

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> > 
> > > Signed-off-by: Scott Branden <scott.branden@broadcom.com>
> > > ---
> > >   lib/test_firmware.c | 26 +++-----------------------
> > >   1 file changed, 3 insertions(+), 23 deletions(-)
> > > 
> > > diff --git a/lib/test_firmware.c b/lib/test_firmware.c
> > > index 0c7fbcf07ac5..9fee2b93a8d1 100644
> > > --- a/lib/test_firmware.c
> > > +++ b/lib/test_firmware.c
> > > @@ -310,27 +310,13 @@ static int test_dev_config_update_bool(const char *buf, size_t size,
> > >   	return ret;
> > >   }
> > > -static ssize_t
> > > -test_dev_config_show_bool(char *buf,
> > > -			  bool config)
> > > +static ssize_t test_dev_config_show_bool(char *buf, bool val)
> > >   {
> > > -	bool val;
> > > -
> > > -	mutex_lock(&test_fw_mutex);
> > > -	val = config;
> > > -	mutex_unlock(&test_fw_mutex);
> > > -
> > >   	return snprintf(buf, PAGE_SIZE, "%d\n", val);
> > >   }
> > > -static ssize_t test_dev_config_show_int(char *buf, int cfg)
> > > +static ssize_t test_dev_config_show_int(char *buf, int val)
> > >   {
> > > -	int val;
> > > -
> > > -	mutex_lock(&test_fw_mutex);
> > > -	val = cfg;
> > > -	mutex_unlock(&test_fw_mutex);
> > > -
> > >   	return snprintf(buf, PAGE_SIZE, "%d\n", val);
> > >   }
> > > @@ -354,14 +340,8 @@ static int test_dev_config_update_u8(const char *buf, size_t size, u8 *cfg)
> > >   	return size;
> > >   }
> > > -static ssize_t test_dev_config_show_u8(char *buf, u8 cfg)
> > > +static ssize_t test_dev_config_show_u8(char *buf, u8 val)
> > >   {
> > > -	u8 val;
> > > -
> > > -	mutex_lock(&test_fw_mutex);
> > > -	val = cfg;
> > > -	mutex_unlock(&test_fw_mutex);
> > > -
> > >   	return snprintf(buf, PAGE_SIZE, "%u\n", val);
> > >   }
> > > -- 
> > > 2.17.1
> > > 
> 

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx
  2020-04-15 16:44     ` Kees Cook
@ 2020-04-16  6:00       ` Luis Chamberlain
  0 siblings, 0 replies; 5+ messages in thread
From: Luis Chamberlain @ 2020-04-16  6:00 UTC (permalink / raw)
  To: Kees Cook
  Cc: Scott Branden, Greg Kroah-Hartman, David Brown, Alexander Viro,
	Shuah Khan, bjorn.andersson, Shuah Khan, Arnd Bergmann,
	Rafael J . Wysocki, linux-kernel, linux-arm-msm, linux-fsdevel,
	BCM Kernel Feedback, Olof Johansson, Andrew Morton,
	Dan Carpenter, Colin Ian King, Takashi Iwai, linux-kselftest,
	Andy Gross

On Wed, Apr 15, 2020 at 09:44:31AM -0700, Kees Cook wrote:
> On Wed, Apr 15, 2020 at 09:28:18AM -0700, Scott Branden wrote:
> > Hi Kees,
> > 
> > On 2020-04-14 8:10 p.m., Kees Cook wrote:
> > > On Tue, Apr 14, 2020 at 05:25:17PM -0700, Scott Branden wrote:
> > > > Remove unnecessary use of test_fw_mutex in test_dev_config_show_xxx
> > > > functions that show simple bool, int, and u8.
> > > I would expect at least a READ_ONCE(), yes?
> > I don't understand why you need a READ_ONCE when removing a mutex around an
> > assignment
> > of a parameter passed into a function being assigned to a local variable.
> > 
> > Could you please explain your expectations.
> 
> Oops, yes, you're right. I misread and was thinking this was reading
> from a global. This looks fine.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>

  Luis

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-04-16  6:00 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2020-04-15  0:25 [PATCH] test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx Scott Branden
2020-04-15  3:10 ` Kees Cook
2020-04-15 16:28   ` Scott Branden
2020-04-15 16:44     ` Kees Cook
2020-04-16  6:00       ` Luis Chamberlain

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