Re: [PATCH v3 04/27] ocxl: Remove unnecessary externs

From: 'Baoquan He' <bhe@redhat.com>
To: Greg Kurz <groug@kaod.org>
Cc: "Alastair D'Silva" <alastair@d-silva.org>,
	"'Alastair D'Silva'" <alastair@au1.ibm.com>,
	"'Aneesh Kumar K . V'" <aneesh.kumar@linux.ibm.com>,
	"'Benjamin Herrenschmidt'" <benh@kernel.crashing.org>,
	"'Paul Mackerras'" <paulus@samba.org>,
	"'Michael Ellerman'" <mpe@ellerman.id.au>,
	"'Frederic Barrat'" <fbarrat@linux.ibm.com>,
	"'Andrew Donnellan'" <ajd@linux.ibm.com>,
	"'Arnd Bergmann'" <arnd@arndb.de>,
	"'Greg Kroah-Hartman'" <gregkh@linuxfoundation.org>,
	"'Andrew Morton'" <akpm@linux-foundation.org>,
	"'Mauro Carvalho Chehab'" <mchehab+samsung@kernel.org>,
	"'David S. Miller'" <davem@davemloft.net>,
	"'Rob Herring'" <robh@kernel.org>,
	"'Anton Blanchard'" <anton@ozlabs.org>,
	"'Krzysztof Kozlowski'" <krzk@kernel.org>,
	"'Mahesh Salgaonkar'" <mahesh@linux.vnet.ibm.com>,
	"'Madhavan Srinivasan'" <maddy@linux.vnet.ibm.com>,
	"'Cédric Le Goater'" <clg@kaod.org>,
	"'Anju T Sudhakar'" <anju@linux.vnet.ibm.com>,
	"'Hari Bathini'" <hbathini@linux.ibm.com>,
	"'Thomas Gleixner'" <tglx@linutronix.de>,
	"'Nicholas Piggin'" <npiggin@gmail.com>,
	"'Masahiro Yamada'" <yamada.masahiro@socionext.com>,
	"'Alexey Kardashevskiy'" <aik@ozlabs.ru>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-nvdimm@lists.01.org, linux-mm@kvack.org
Subject: Re: [PATCH v3 04/27] ocxl: Remove unnecessary externs
Date: Wed, 26 Feb 2020 22:15:23 +0800	[thread overview]
Message-ID: <20200226141523.GI4937@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20200226100102.0aab7dda@bahia.home>

On 02/26/20 at 10:01am, Greg Kurz wrote:
> On Wed, 26 Feb 2020 19:26:34 +1100
> "Alastair D'Silva" <alastair@d-silva.org> wrote:
> 
> > > -----Original Message-----
> > > From: Baoquan He <bhe@redhat.com>
> > > Sent: Wednesday, 26 February 2020 7:15 PM
> > > To: Alastair D'Silva <alastair@au1.ibm.com>
> > > Cc: alastair@d-silva.org; Aneesh Kumar K . V
> > > <aneesh.kumar@linux.ibm.com>; Oliver O'Halloran <oohall@gmail.com>;
> > > Benjamin Herrenschmidt <benh@kernel.crashing.org>; Paul Mackerras
> > > <paulus@samba.org>; Michael Ellerman <mpe@ellerman.id.au>; Frederic
> > > Barrat <fbarrat@linux.ibm.com>; Andrew Donnellan <ajd@linux.ibm.com>;
> > > Arnd Bergmann <arnd@arndb.de>; Greg Kroah-Hartman
> > > <gregkh@linuxfoundation.org>; Dan Williams <dan.j.williams@intel.com>;
> > > Vishal Verma <vishal.l.verma@intel.com>; Dave Jiang
> > > <dave.jiang@intel.com>; Ira Weiny <ira.weiny@intel.com>; Andrew Morton
> > > <akpm@linux-foundation.org>; Mauro Carvalho Chehab
> > > <mchehab+samsung@kernel.org>; David S. Miller <davem@davemloft.net>;
> > > Rob Herring <robh@kernel.org>; Anton Blanchard <anton@ozlabs.org>;
> > > Krzysztof Kozlowski <krzk@kernel.org>; Mahesh Salgaonkar
> > > <mahesh@linux.vnet.ibm.com>; Madhavan Srinivasan
> > > <maddy@linux.vnet.ibm.com>; Cédric Le Goater <clg@kaod.org>; Anju T
> > > Sudhakar <anju@linux.vnet.ibm.com>; Hari Bathini
> > > <hbathini@linux.ibm.com>; Thomas Gleixner <tglx@linutronix.de>; Greg
> > > Kurz <groug@kaod.org>; Nicholas Piggin <npiggin@gmail.com>; Masahiro
> > > Yamada <yamada.masahiro@socionext.com>; Alexey Kardashevskiy
> > > <aik@ozlabs.ru>; linux-kernel@vger.kernel.org; linuxppc-
> > > dev@lists.ozlabs.org; linux-nvdimm@lists.01.org; linux-mm@kvack.org
> > > Subject: Re: [PATCH v3 04/27] ocxl: Remove unnecessary externs
> > > 
> > > On 02/21/20 at 02:26pm, Alastair D'Silva wrote:
> > > > From: Alastair D'Silva <alastair@d-silva.org>
> > > >
> > > > Function declarations don't need externs, remove the existing ones so
> > > > they are consistent with newer code
> > > >
> > > > Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> > > > ---
> > > >  arch/powerpc/include/asm/pnv-ocxl.h | 32 ++++++++++++++---------------
> > > >  include/misc/ocxl.h                 |  6 +++---
> > > >  2 files changed, 18 insertions(+), 20 deletions(-)
> > > >
> > > > diff --git a/arch/powerpc/include/asm/pnv-ocxl.h
> > > > b/arch/powerpc/include/asm/pnv-ocxl.h
> > > > index 0b2a6707e555..b23c99bc0c84 100644
> > > > --- a/arch/powerpc/include/asm/pnv-ocxl.h
> > > > +++ b/arch/powerpc/include/asm/pnv-ocxl.h
> > > > @@ -9,29 +9,27 @@
> > > >  #define PNV_OCXL_TL_BITS_PER_RATE       4
> > > >  #define PNV_OCXL_TL_RATE_BUF_SIZE
> > > ((PNV_OCXL_TL_MAX_TEMPLATE+1) * PNV_OCXL_TL_BITS_PER_RATE / 8)
> > > >
> > > > -extern int pnv_ocxl_get_actag(struct pci_dev *dev, u16 *base, u16
> > > *enabled,
> > > > -			u16 *supported);
> > > 
> > > It works w or w/o extern when declare functions. Searching 'extern'
> > > under include can find so many functions with 'extern' adding. Do we have
> > a
> > > explicit standard if we should add or remove 'exter' in function
> > declaration?
> > > 
> > > I have no objection to this patch, just want to make clear so that I can
> > handle
> > > it w/o confusion.
> > > 
> > > Thanks
> > > Baoquan
> > > 
> > 
> > For the OpenCAPI driver, we have settled on not having 'extern' on
> > functions.
> > 
> > I don't think I've seen a standard that supports or refutes this, but it
> > does not value add.
> > 
> 
> FWIW this is a warning condition for checkpatch:
> 
> $ ./scripts/checkpatch.pl --strict -f include/misc/ocxl.h

Good to know, thanks.

I didn't know checkpatch.pl can run on header file directly. Tried to
check patch with '--strict -f', the below info doesn't appear. But it
does give out below information when run on header file.

> 
> [...]
> 
> CHECK: extern prototypes should be avoided in .h files
> #176: FILE: include/misc/ocxl.h:176:
> +extern int ocxl_afu_irq_alloc(struct ocxl_context *ctx, int *irq_id);
> 
> [...]
> 
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