diff mbox series

test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx

Message ID 20200415002517.4328-1-scott.branden@broadcom.com
State New
Headers show
Series test_firmware: remove unnecessary test_fw_mutex in test_dev_config_show_xxx | expand

Commit Message

Scott Branden April 15, 2020, 12:25 a.m. UTC
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(-)

Comments

Scott Branden April 15, 2020, 4:28 p.m. UTC | #1
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
>>
Kees Cook April 15, 2020, 4:44 p.m. UTC | #2
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
> > > 
>
Luis Chamberlain April 16, 2020, 6 a.m. UTC | #3
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
diff mbox series

Patch

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);
 }