From: Michael Ellerman mpe@ellerman.id.au Date: 2020-03-17 19:22:13 To:"王文虎" wenhu.wang@vivo.com cc: Benjamin Herrenschmidt benh@kernel.crashing.org,Paul Mackerras paulus@samba.org,Allison Randal allison@lohutok.net,Richard Fontana rfontana@redhat.com,Greg Kroah-Hartman gregkh@linuxfoundation.org,Thomas Gleixner tglx@linutronix.de,linuxppc-dev@lists.ozlabs.org,linux-kernel@vger.kernel.org,trivial@kernel.org,kernel@vivo.com,stable stable@vger.kernel.org Subject: Re: [PATCH v3] powerpc/fsl-85xx: fix compile error>王文虎 wenhu.wang@vivo.com writes:
From: Michael Ellerman mpe@ellerman.id.au Date: 2020-03-16 17:41:12 To:WANG Wenhu wenhu.wang@vivo.com,Benjamin Herrenschmidt benh@kernel.crashing.org,Paul Mackerras paulus@samba.org,WANG Wenhu wenhu.wang@vivo.com,Allison Randal allison@lohutok.net,Richard Fontana rfontana@redhat.com,Greg Kroah-Hartman gregkh@linuxfoundation.org,Thomas Gleixner tglx@linutronix.de,linuxppc-dev@lists.ozlabs.org,linux-kernel@vger.kernel.org cc: trivial@kernel.org,kernel@vivo.com,stable stable@vger.kernel.org Subject: Re: [PATCH v3] powerpc/fsl-85xx: fix compile error>WANG Wenhu wenhu.wang@vivo.com writes:
Include "linux/of_address.h" to fix the compile error for mpc85xx_l2ctlr_of_probe() when compiling fsl_85xx_cache_sram.c.
CC arch/powerpc/sysdev/fsl_85xx_l2ctlr.o arch/powerpc/sysdev/fsl_85xx_l2ctlr.c: In function ‘mpc85xx_l2ctlr_of_probe’: arch/powerpc/sysdev/fsl_85xx_l2ctlr.c:90:11: error: implicit declaration of function ‘of_iomap’; did you mean ‘pci_iomap’? [-Werror=implicit-function-declaration] l2ctlr = of_iomap(dev->dev.of_node, 0); ^~~~~~~~ pci_iomap arch/powerpc/sysdev/fsl_85xx_l2ctlr.c:90:9: error: assignment makes pointer from integer without a cast [-Werror=int-conversion] l2ctlr = of_iomap(dev->dev.of_node, 0); ^ cc1: all warnings being treated as errors scripts/Makefile.build:267: recipe for target 'arch/powerpc/sysdev/fsl_85xx_l2ctlr.o' failed make[2]: *** [arch/powerpc/sysdev/fsl_85xx_l2ctlr.o] Error 1
Fixes: commit 6db92cc9d07d ("powerpc/85xx: add cache-sram support")
The syntax is:
Fixes: 6db92cc9d07d ("powerpc/85xx: add cache-sram support")
Cc: stable stable@vger.kernel.org
The commit above went into v2.6.37.
So no one has noticed this bug since then, how? Or did something else change to expose the problem?
Actually a hard question to answer cause it also left me scratching for long. However, I can not find right or definite answer.
Oh, actually it's fairly straight forward, the code can't be built at all in upstream because CONFIG_FSL_85XX_CACHE_SRAM is not selectable or selected by anything.
Yeah, sure that is the reason, and I meant it was hard to figure out why nobody had ever compiled the driver with FSL_85XX_CACHE_SRAM enabled until me.
You sent a patch previously to make it selectable, which Scott thought was a bad idea.
So this whole file is dead code as far as I'm concerned, so patches for it definitely do not need to go to stable.
If you want to add a user for it then please send a series doing that, and this commit can be the first.
For this, as you mentioned, it is dead and do not need to be applied to any stable. And I recommand the patch as a unit itself cause our module which uses it is still under developing, and the module itself would be taken as a complete logical block. Also it would take some time.
Thanks, Wenhu
cheers