Re: [PATCH] SCSI: fix isa/pcmcia compile problem

From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Tejun Heo <htejun@gmail.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
	fischer@norbit.de, Andy Whitcroft <apw@shadowen.org>,
	Balbir Singh <balbir@linux.vnet.ibm.com>,
	Samuel Ortiz <samuel@sortiz.org>
Subject: Re: [PATCH] SCSI: fix isa/pcmcia compile problem
Date: Fri, 18 Jan 2008 17:47:56 -0600	[thread overview]
Message-ID: <1200700076.3111.80.camel@localhost.localdomain> (raw)
In-Reply-To: <1200699173.3111.77.camel@localhost.localdomain>


On Fri, 2008-01-18 at 17:32 -0600, James Bottomley wrote:
> On Sat, 2008-01-19 at 08:27 +0900, Tejun Heo wrote:
> > James Bottomley wrote:
> > > On Fri, 2008-01-18 at 16:20 +0900, Tejun Heo wrote:
> > >> aha152x.c and fdomain are built twice - once for the isa driver and
> > >> once for the PCMCIA one.  Through #ifdefs, the compiled codes are
> > >> slightly different; thus, global symbols need to be given different
> > >> names depending on which flavor is being built.  This patch adds
> > >> GLOBAL() macro to aha152x.h and fdomain.h which change the symbol
> > >> depending on PCMCIA.
> > >>
> > >> This bug has always existed but has been masked by the fact the
> > >> drivers/scsi/pcmcia used subdir-(y|m) instead of obj-(y|m) which made
> > >> drivers/scsi/pcmcia/built_in.o not linked into the kernel and thus
> > >> avoided the duplicate symbols during compilation.
> > >>
> > >> Signed-off-by: Tejun Heo <htejun@gmail.com>
> > >> ---
> > >> Ah... missed that one.  Here's the updated version.
> > > 
> > > Actually, isn't the better fix just to return to the original behaviour?
> > > 
> > > As you pointed out, using the subdir instead of obj meant that although
> > > the modules were built, the drivers were never linked into the main
> > > kernel.  According to the records, this has been the default forever, so
> > > there can be no-one anywhere relying on these drivers being built in.
> > > Actually, as old style pcmcia drivers, I'm not sure there's much value
> > > building them into the kernel anyway.
> > > 
> > > So just modify scsi/pcmcia/Kconfig to make them all depend on m.
> > 
> > Yeap, there is no problem if you don't allow them to be linked into the
> > kernel.  If that's how you want it, please go ahead.
> > 
> > I personally think it's a bit odd to disallow building into kernel
> > because of the peculiarity of the implementation (including c files and
> > compiling them slightly differently) and also no one reporting doesn't
> > necessarily mean no one has attempted it and failed.
> 
> Heh ... I'll make you a deal.  Find just one user of one of these
> drivers who can make use of them built in, and I'll apply the patch.  
> 
> I'm just a bit reluctant to touch these drivers, since they're all
> incredibly ancient.  We don't have good luck with simple transformation
> patches on the older drivers ... and it seems to take months before
> anyone notices there's a problem.

This is the patch that will return them to their original behaviour.

James

---

diff --git a/drivers/scsi/pcmcia/Kconfig b/drivers/scsi/pcmcia/Kconfig
index fa481b5..53857c6 100644
--- a/drivers/scsi/pcmcia/Kconfig
+++ b/drivers/scsi/pcmcia/Kconfig
@@ -6,7 +6,8 @@ menuconfig SCSI_LOWLEVEL_PCMCIA
 	bool "PCMCIA SCSI adapter support"
 	depends on SCSI!=n && PCMCIA!=n
 
-if SCSI_LOWLEVEL_PCMCIA && SCSI && PCMCIA
+# drivers have problems when build in, so require modules
+if SCSI_LOWLEVEL_PCMCIA && SCSI && PCMCIA && m
 
 config PCMCIA_AHA152X
 	tristate "Adaptec AHA152X PCMCIA support"


