Re: [PATCH] drivers: Let several drivers depends on HAS_IOMEM for 'devm_ioremap_resource'

On 07/17/2014 06:58 PM, Richard Weinberger wrote:

Am 17.07.2014 12:28, schrieb Arnd Bergmann:

quoted

On Thursday 17 July 2014 11:26:57 Richard Weinberger wrote:

quoted

Am 17.07.2014 11:20, schrieb Arnd Bergmann:

quoted

On Thursday 17 July 2014 09:27:58 Chen Gang wrote:

quoted

                                         gfp_t gfp_mask, unsigned int order);
 extern void devm_free_pages(struct device *dev, unsigned long addr);
 
+#ifdef CONFIG_HAS_IOMEM
 void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
+#elif defined(CONFIG_COMPILE_TEST)
+static inline void __iomem *devm_ioremap_resource(struct device *dev,
+                                               struct resource *res)
+{
+       pr_warn("no hardware io memory, only for COMPILE_TEST\n");
+       return (__force void __iomem *)ERR_PTR(-ENXIO);
+}
+#endif /* CONFIG_HAS_IOMEM || CONFIG_COMPILE_TEST */
 
 /* allows to add/remove a custom action to devres stack */

To be honest, I think it's a bad idea to introduce wrappers functions
that are only available when CONFIG_COMPILE_TEST is set.

COMPILE_TEST is a great tool in general, but it has its limits.
In particular, the case for !CONFIG_IOMEM is completely obscure
and we won't find any bugs by allowing more drivers to be built
in those configurations, but attempting to do it would cause
endless churn by changing each instance of 'depends on HAS_IOMEM'
to 'depends on HAS_IOMEM || COMPILE_TEST'.

Note that s390 no has gained support for IOMEM, tile has it most
of the time (when PCI is enabled, so you get it in half the
test builds already), score should set HAS_IOMEM and doesn't
even have public compilers, and uml doesn't even compile in
latest mainline. Nothing else ever sets NO_IOMEM.

Huh? UML (v3.16-rc5-143-gb6603fe) builds fine here. What build issue are you facing?

This is what I got upon trying earlier. I have not attempted to look into
why this is happening. Note this is on linux-next from yesterday,
not mainline as I incorrectly stated above.

In file included from ../arch/um/include/asm/fixmap.h:58:0,
                 from ../arch/um/include/asm/pgtable.h:11,
                 from ../include/linux/mm.h:51,
                 from ../kernel/uid16.c:6:
../include/asm-generic/fixmap.h: In function 'fix_to_virt':
../include/asm-generic/fixmap.h:31:2: error: size of unnamed array is negative
  BUILD_BUG_ON(idx >= __end_of_fixed_addresses);

So, this is next-20140716?
I don't see the fixmap issue you're reporting, also not on the most recent next.

All I see is the known ext4 issue with CONFIG_SMP=n:

fs/ext4/super.c: In function ‘ext4_commit_super’:
fs/ext4/super.c:4547:41: error: ‘struct percpu_counter’ has no member named ‘counters’
  if (EXT4_SB(sb)->s_freeclusters_counter.counters)
                                         ^
fs/ext4/super.c:4551:39: error: ‘struct percpu_counter’ has no member named ‘counters’
  if (EXT4_SB(sb)->s_freeinodes_counter.counters)

Yeah, and I have notified to ext4 related maintainer, yesterday, and he
has already send fix patch for it, I guess it will be integrated into
main line soon.


Thanks.
-- 
Chen Gang

Open, share, and attitude like air, water, and life which God blessed
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