Re: [dpdk-dev] [PATCH v2] net/ixgbe: clean up rte_eth_dev_info_get

["Lu, Wenzhuo" <wenzhuo.lu@intel.com>]

> -----Original Message-----
> From: Bie, Tiwei
> Sent: Monday, February 6, 2017 12:57 PM
> To: Lu, Wenzhuo
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2] net/ixgbe: clean up rte_eth_dev_info_get
> 
> On Mon, Feb 06, 2017 at 11:45:41AM +0800, Lu, Wenzhuo wrote:
> > Hi Tiwei,
> >
> > > -----Original Message-----
> > > From: Bie, Tiwei
> > > Sent: Monday, February 6, 2017 11:08 AM
> > > To: Lu, Wenzhuo
> > > Cc: dev@dpdk.org
> > > Subject: Re: [dpdk-dev] [PATCH v2] net/ixgbe: clean up
> > > rte_eth_dev_info_get
> > >
> > > On Mon, Feb 06, 2017 at 10:59:42AM +0800, Lu, Wenzhuo wrote:
> > > > Hi Tiwei,
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Bie, Tiwei
> > > > > Sent: Monday, February 6, 2017 10:51 AM
> > > > > To: Lu, Wenzhuo
> > > > > Cc: dev@dpdk.org
> > > > > Subject: Re: [dpdk-dev] [PATCH v2] net/ixgbe: clean up
> > > > > rte_eth_dev_info_get
> > > > >
> > > > > On Mon, Feb 06, 2017 at 10:41:28AM +0800, Lu, Wenzhuo wrote:
> > > > > > Hi Tiwei,
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Bie, Tiwei
> > > > > > > Sent: Monday, February 6, 2017 10:31 AM
> > > > > > > To: Lu, Wenzhuo
> > > > > > > Cc: dev@dpdk.org
> > > > > > > Subject: Re: [dpdk-dev] [PATCH v2] net/ixgbe: clean up
> > > > > > > rte_eth_dev_info_get
> > > > > > >
> > > > > > > On Mon, Feb 06, 2017 at 10:09:32AM +0800, Wenzhuo Lu wrote:
> > > > > > > [...]
> > > > > > > >  static void ixgbe_dcb_init(struct ixgbe_hw *hw, struct
> > > > > > > > ixgbe_dcb_config *dcb_config); -static int
> > > > > > > > is_ixgbe_pmd(const char *driver_name);
> > > > > > > > +static int is_device_supported(struct rte_eth_dev *dev,
> > > > > > > > +struct eth_driver *drv);
> > > > > > > >
> > > > > > >
> > > > > > > Should be:
> > > > > > > static bool is_device_supported(struct rte_eth_dev *dev,
> > > > > > > struct eth_driver *drv);
> > > > > > O, forget to change it. Thanks.
> > > > > >
> > > > > > >
> > > > > > > >  /* For Virtual Function support */  static int
> > > > > > > > eth_ixgbevf_dev_init(struct rte_eth_dev *eth_dev); @@
> > > > > > > > -4380,16 +4380,14 @@ static int
> > > > > > > ixgbevf_dev_xstats_get_names(__rte_unused struct rte_eth_dev
> > > > > > > *dev,
> > > > > > > >  	ixgbe_add_rar(dev, addr, 0, 0);  }
> > > > > > > >
> > > > > > > > -static int
> > > > > > > > -is_ixgbe_pmd(const char *driver_name)
> > > > > > > > +static bool
> > > > > > > > +is_device_supported(struct rte_eth_dev *dev, struct
> > > > > > > > +eth_driver
> > > > > > > > +*drv)
> > > > > > > >  {
> > > > > > > > -	if (!strstr(driver_name, "ixgbe"))
> > > > > > > > -		return -ENOTSUP;
> > > > > > > > +	if (strcmp(dev->driver->pci_drv.driver.name,
> > > > > > > > +		   drv->pci_drv.driver.name))
> > > > > > > > +		return FALSE;
> > > > > > > >
> > > > > > >
> > > > > > > It would be better to use `false' instead of `FALSE'.
> > > > > > I see both 'false' and 'FALSE' are defined and used. Is there
> > > > > > any reason that
> > > > > 'false' is better?
> > > > > >
> > > > >
> > > > > I think `true' and `false' are standard keywords defined and
> > > > > reserved by C. So I think it would be better to use them if the
> > > > > return type is
> > > `bool'.
> > > > O, there's no 'bool' in C. You have to define it. The same for 'false' and
> 'true'.
> > > >
> > >
> > > The `bool', `true' and `false' are all standard keywords defined and
> > > reserved by C, although the stdbool.h is not used in ixgbe.
> > >
> > > C adds this support by introducing a new header stdbool.h:
> > >
> > > #ifndef __bool_true_false_are_defined
> > > #define __bool_true_false_are_defined   1
> > >
> > > #ifndef __cplusplus
> > >
> > > #define false   0
> > > #define true    1
> > >
> > > #define bool    _Bool
> > > #if __STDC_VERSION__ < 199901L && __GNUC__ < 3 &&
> > > !defined(__INTEL_COMPILER)
> > > typedef int     _Bool;
> > > #endif
> > O, you're talking about C99. _Bool is a  keyword added by it. 'bool', 'true',
> 'false' are  not. That's why this header file have to define them.
> >
> 
> C99 added all those as keyword, although doesn't implement all of them as
> the builtin type (e.g. int). All of them are standard keywords defined by C99.
> The `bool', `true' and `false' are defined in section 7.16 of the C99 spec [1] and
> implemented as macros:
> 
> 7.16 Boolean type and values <stdbool.h>
> 
> 1 The header <stdbool.h> defines four macros.
> 
> 2 The macro
>           bool
> expands to _Bool.
> 
> 3 The remaining three macros are suitable for use in #if preprocessing
> directives. They are
>           true
> which expands to the integer constant 1,
>           false
> which expands to the integer constant 0, and
>           __bool_true_false_are_defined
> which expands to the integer constant 1.
> 
> 4 Notwithstanding the provisions of 7.1.3, a program may undefine and
> perhaps then redefine the macros bool, true, and false.222)
> 
> Footnotes
> 
> 222) See ''future library directions'' (7.26.7).
> 
> [1] http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf
O, I see the divergence. It's about the term 'keyword'. I only count '6.4.1 Keywords'. 
Anyway, as both 'false'/'true' and 'FALSE'/'TRUE' are defined. I don’t know why we cannot use any of them. If 'FALSE'/'TRUE' is not preferred, better create a new patch to clean them up.

> 
> Best regards,
> Tiwei Bie