Le 04/03/2018 à 11:55, Michael Ellerman a écrit :
Mathieu Malaterre <ma...@debian.org> writes:
Rewrite comparison since all values compared are of type `unsigned long`.
Fix a warning (treated as error in W=1):
CC arch/powerpc/kernel/irq.o
In file included from ./include/linux/bug.h:5:0,
from ./include/linux/cpumask.h:13,
from ./include/linux/smp.h:13,
from ./include/linux/kernel_stat.h:5,
from arch/powerpc/kernel/irq.c:35:
./include/linux/dma-mapping.h: In function ‘dma_map_resource’:
./arch/powerpc/include/asm/page.h:129:32: error: comparison of unsigned expression
>= 0 is always true [-Werror=type-limits]
#define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && (pfn) < max_mapnr)
^
Suggested-by: Segher Boessenkool <seg...@kernel.crashing.org>
Signed-off-by: Mathieu Malaterre <ma...@debian.org>
---
arch/powerpc/include/asm/page.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 8da5d4c1cab2..19dea64e7ed2 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -126,7 +126,8 @@ extern long long virt_phys_offset;
#ifdef CONFIG_FLATMEM
#define ARCH_PFN_OFFSET ((unsigned long)(MEMORY_START >>
PAGE_SHIFT))
-#define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && (pfn) < max_mapnr)
+#define pfn_valid(pfn) \
+ (((pfn) - ARCH_PFN_OFFSET) < (max_mapnr - ARCH_PFN_OFFSET))
I'm not a big fan of this one, because the original code is *far* more
obvious as to what it's doing.
I'm not sure if we can make this one a static inline, or whether that
would help, but it would be worth investigating.
The following seems to give a good result:
diff --git a/arch/powerpc/include/asm/page.h
b/arch/powerpc/include/asm/page.h
index 8da5d4c1cab2..6f74938483b7 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -126,7 +126,15 @@ extern long long virt_phys_offset;
#ifdef CONFIG_FLATMEM
#define ARCH_PFN_OFFSET ((unsigned long)(MEMORY_START >>
PAGE_SHIFT))
-#define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && (pfn) < max_mapnr)
+#ifndef __ASSEMBLY__
+extern unsigned long max_mapnr;
+static inline bool pfn_valid(unsigned long pfn)
+{
+ unsigned long min_pfn = ARCH_PFN_OFFSET;
+
+ return pfn >= min_pfn && pfn < max_mapnr;
+}
+#endif
#endif
#define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
Christophe
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