Re: [PATCH 14/19] drivers/scsi: Use PCI_VDEVICE

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Wed, 2009-06-24 at 22:13 -0700, Joe Perches wrote:
> Signed-off-by: Joe Perches <joe@perches.com>

OK, so there's no description whatsoever how am I supposed to divine the
reasons for doing this?

Because if I look at an example:

> --- a/drivers/scsi/3w-9xxx.c
> +++ b/drivers/scsi/3w-9xxx.c
> @@ -2278,14 +2278,10 @@ out_disable_device:
>  
>  /* PCI Devices supported by this driver */
>  static struct pci_device_id twa_pci_tbl[] __devinitdata = {
> -	{ PCI_VENDOR_ID_3WARE, PCI_DEVICE_ID_3WARE_9000,
> -	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
> -	{ PCI_VENDOR_ID_3WARE, PCI_DEVICE_ID_3WARE_9550SX,
> -	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
> -	{ PCI_VENDOR_ID_3WARE, PCI_DEVICE_ID_3WARE_9650SE,
> -	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
> -	{ PCI_VENDOR_ID_3WARE, PCI_DEVICE_ID_3WARE_9690SA,
> -	  PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
> +	{ PCI_VDEVICE(3WARE, PCI_DEVICE_ID_3WARE_9000), 0},
> +	{ PCI_VDEVICE(3WARE, PCI_DEVICE_ID_3WARE_9550SX), 0},
> +	{ PCI_VDEVICE(3WARE, PCI_DEVICE_ID_3WARE_9650SE), 0},
> +	{ PCI_VDEVICE(3WARE, PCI_DEVICE_ID_3WARE_9690SA), 0},

It appears to take PCI matching on vendor device with any subvendor,
device and reproduce the results with a macro, which, for good measure
pastes PCI_VENDOR_ID on to the first argument but *doesn't* paste
PCI_DEVICE_ID on to the second?

So it transforms a relatively opaque initialiser which most people would
have to look up in pci.h into another relatively opaque initialiser
indirected via a macro, so now I have to look up both the structure and
the macro to figure out what's going on.

If that's all it does, I'm having a hard time seeing any actual
improvement here.

James