Re: [BUILD FAILURE 01/04] Next June 04:PPC64 randconfig [drivers/staging/comedi/drivers.o]

On Fri, Jun 05, 2009 at 01:26:25PM -0500, Subrata Modak wrote:

quoted

On Thu, 2009-06-04 at 22:40 +0200, Geert Uytterhoeven wrote:
On Thu, Jun 4, 2009 at 20:07, Greg KH [off-list ref] wrote:

quoted

On Thu, Jun 04, 2009 at 07:01:32PM +0530, Subrata Modak wrote:

quoted

CC [M]  drivers/staging/comedi/drivers.o
drivers/staging/comedi/drivers.c: In function ‘comedi_buf_alloc’:
drivers/staging/comedi/drivers.c:496: error: ‘PAGE_KERNEL_NOCACHE’ undeclared (first use in this function)
drivers/staging/comedi/drivers.c:496: error: (Each undeclared identifier is reported only once
drivers/staging/comedi/drivers.c:496: error: for each function it appears in.)
make[3]: *** [drivers/staging/comedi/drivers.o] Error 1
make[2]: *** [drivers/staging/comedi] Error 2
make[1]: *** [drivers/staging] Error 2
make: *** [drivers] Error 2

Is it still normal to expect this failure ?

No.

quoted

I reported them long back during April:
http://www.gossamer-threads.com/lists/linux/kernel/1065227,

Yes, and I took some patches that were supposed to fix this.  I can't
duplicate this here, care to send a patch that would fix it?

I tried this. But, with some catch. ‘PAGE_KERNEL_NOCACHE’ seems to be the
choice for majority of architectures like frv, m32r, sh, x86, etc, as Geert
mentions below. However, i believe POWERPC defines it as ‘PAGE_KERNEL_NC‘
found at arch/powerpc/include/asm/pte-common.h.

Paul/Banjamin,
Can you please confirm this ?

The below patch fixes the build error.

Ick, that's a mess.

+#ifdef __powerpc64__
+				vmap(pages, n_pages, VM_MAP,
+				PAGE_KERNEL_NC);
+#else
 				vmap(pages, n_pages, VM_MAP,
 				PAGE_KERNEL_NOCACHE);
+#endif

Should the comedi layer just not be using PAGE_KERNEL_NOCACHE here?  I
can't believe that we need to do something like this in a driver.  What
should the proper fix for this be?

thanks,

greg k-h