Re: [PATCH 1/5] serial: 8250_pci: use DEFINE_PCI_DEVICE_TABLE macro

[Joe Perches <joe@perches.com>]

On Thu, 2013-11-28 at 14:29 +0900, Jingoo Han wrote:
> On Thursday, November 28, 2013 1:08 PM, Greg Kroah-Hartman wrote:
> > On Thu, Nov 28, 2013 at 10:55:35AM +0900, Jingoo Han wrote:
> > > This macro is used to create a struct pci_device_id array.
> > 
> > Yeah, and it's a horrid macro that deserves to be removed, please don't
> > use it in more places.
> > 
> > Actually, if you could just remove it, that would be best, sorry, I'm
> > not going to take these patches.
> 
> (+cc Joe Perches, Andrew Morton, Andy Whitcroft)
> 
> Hi Joe Perches,
> 
> Would you fix checkpatch.pl about DEFINE_PCI_DEVICE_TABLE?
> Currently, checkpatch.pl guides to use DEFINE_PCI_DEVICE_TABLE
> as below.
> 
>   WARNING: Use DEFINE_PCI_DEVICE_TABLE for struct pci_device_id
>   #331: FILE: drivers/usb/host/ehci-pci.c:331:
>   +static const struct pci_device_id pci_ids [] = { {
> 
> However, Greg Kroah-Hartman mentioned that DEFINE_PCI_DEVICE_TABLE
> shouldn't be used anymore.
> 
> So, would you change checkpatch.pl in order to guide to use
> struct pci_device_id instead of DEFINE_PCI_DEVICE_TABLE?
> 
> For example,
>   WARNING: Use struct pci_device_id instead of DEFINE_PCI_DEVICE_TABLE

The documentation doesn't agree with Greg.

Documentation/PCI/pci.txt:

The ID table is an array of struct pci_device_id entries ending with an
all-zero entry; use of the macro DEFINE_PCI_DEVICE_TABLE is the preferred
method of declaring the table.

Neither does the kernel tree:

$ git grep -w DEFINE_PCI_DEVICE_TABLE | wc -l
410

$ git grep -E "\bstruct\s+pci_device_id\s+\w+\s*\[\s*\]\s*=" | wc -l
376

Most of the 376 should be const and are not.

$ git grep -E "\bconst\s+struct\s+pci_device_id\s+\w+\s*\[\s*\]\s*=" | wc -l
155

Everything that uses DEFINE_PCI_DEVICE_TABLE is const.

$ git grep -A1 -E "define\s+DEFINE_PCI_DEVICE_TABLE"
include/linux/pci.h:#define DEFINE_PCI_DEVICE_TABLE(_table) \
include/linux/pci.h-    const struct pci_device_id _table[]