Re: [PATCH v3] PCI: Add pci_iounmap

[Yang Yingliang <yangyingliang@xxxxxxxxxx>]

Hi,

On 2020/9/2 2:05, George Cherian wrote:
> Hi Yang,
>
> > -----Original Message-----
> > From: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> > Sent: Tuesday, September 1, 2020 6:59 PM
> > To: George Cherian <gcherian@xxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx;
> > linux-arch@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx
> > Cc: kbuild-all@xxxxxxxxxxxx; bhelgaas@xxxxxxxxxx; arnd@xxxxxxxx;
> > mst@xxxxxxxxxx
> > Subject: Re: [PATCH v3] PCI: Add pci_iounmap
> >
> >
> >
> >
> > On 2020/8/25 9:25, kernel test robot wrote:
> > > Hi George,
> > >
> > > I love your patch! Yet something to improve:
> > >
> > > [auto build test ERROR on pci/next]
> > > [also build test ERROR on linux/master linus/master asm-generic/master
> > > v5.9-rc2 next-20200824] [If your patch is applied to the wrong git tree,
> > kindly drop us a note.
> > > And when submitting patch, we suggest to use '--base' as documented in
> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__git-
> > 2Dscm.com_doc
> > > s_git-2Dformat-2Dpatch&d=DwIC-
> > g&c=nKjWec2b6R0mOyPaz7xtfQ&r=TjMsEFPc7di
> > rkF6u2D3eSIS0cA8FeYpzRkkMzr4aCbk&m=dvtRkwC273FmalEZE_KonLRWrIV
> > WLSWfG61
> > > NWTWG5LI&s=ycW6SZOVRuKAm3YwdhyAuSh22oPuengSMVuv-
> > EwaUew&e= ]
> > > url:    https://urldefense.proofpoint.com/v2/url?u=https-
> > 3A__github.com_0day-2Dci_linux_commits_George-2DCherian_PCI-2DAdd-
> > 2Dpci-5Fiounmap_20200824-2D212149&d=DwIC-
> > g&c=nKjWec2b6R0mOyPaz7xtfQ&r=TjMsEFPc7dirkF6u2D3eSIS0cA8FeYpzRkk
> > Mzr4aCbk&m=dvtRkwC273FmalEZE_KonLRWrIVWLSWfG61NWTWG5LI&s=6c
> > UOYHeDOBZ0HaFc2z-vaDgDmbIK4LCBRt9kNkn1sto&e=
> > > base:   https://urldefense.proofpoint.com/v2/url?u=https-
> > 3A__git.kernel.org_pub_scm_linux_kernel_git_helgaas_pci.git&d=DwIC-
> > g&c=nKjWec2b6R0mOyPaz7xtfQ&r=TjMsEFPc7dirkF6u2D3eSIS0cA8FeYpzRkk
> > Mzr4aCbk&m=dvtRkwC273FmalEZE_KonLRWrIVWLSWfG61NWTWG5LI&s=h-
> > TMyLlEdAwew-u52q4dgWBUMgm0ys-xKzvOO86e1Lw&e=  next
> > > config: powerpc-allyesconfig (attached as .config)
> > > compiler: powerpc64-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1
> > > build):
> > >           wget https://urldefense.proofpoint.com/v2/url?u=https-
> > 3A__raw.githubusercontent.com_intel_lkp-
> > 2Dtests_master_sbin_make.cross&d=DwIC-
> > g&c=nKjWec2b6R0mOyPaz7xtfQ&r=TjMsEFPc7dirkF6u2D3eSIS0cA8FeYpzRkk
> > Mzr4aCbk&m=dvtRkwC273FmalEZE_KonLRWrIVWLSWfG61NWTWG5LI&s=az
> > QcL0MQmPpr9UfvyBSSdQiu1UbjJgFrzNJOtcZ_--E&e=  -O ~/bin/make.cross
> > >           chmod +x ~/bin/make.cross
> > >           # save the attached .config to linux build tree
> > >           COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0
> > > make.cross ARCH=powerpc
> > >
> > > If you fix the issue, kindly add following tag as appropriate
> > > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > >
> > > All errors (new ones prefixed by >>):
> > >
> > >      powerpc64-linux-ld: lib/pci_iomap.o: in function `__crc_pci_iounmap':
> > > > > (.rodata+0x10): multiple definition of `__crc_pci_iounmap';
> > > > > lib/iomap.o:(.rodata+0x68): first defined here
> > EXPORT_SYMBOL(pci_iounmap) in lib/iomap.c need be removed.
> I really don't think that is the way to fix this. I have also seen your other patch
> in which iomap being moved out of lib/iomap.c to header file.
>
> There was a reason for moving iomap and its variants to a lib since most of
> the arch's implementation of map was similar. Whereas the unmap had multiple
> implementation per arch's. So, the lib/iomap never implemented the generic unmap.
>
> I see either of the following solution.
> a. Have an arm64 specific implementation for the unmap function.
> Or
> b. something on the lines of v2[1], which accommodates all the arch's but has the #ifdef
> for which Bjorn raised his concerns.
I think 'a' may be better, and I have already make a patch, I can send 
it after testing.
> Bjorn, any comments?
>
> Regards
> -George
>
> [1] - https://lkml.org/lkml/2020/8/20/28