On 02/08/2013 12:28 PM, Dave Hansen wrote:
#endif
diff -puN include/linux/mm.h~clean-up-highmem-checks include/linux/mm.h
--- linux-2.6.git/include/linux/mm.h~clean-up-highmem-checks 2013-02-08
08:42:37.295222148 -0800
+++ linux-2.6.git-dave/include/linux/mm.h 2013-02-08 09:01:49.758254468
-0800
@@ -1771,5 +1771,18 @@ static inline unsigned int debug_guardpa
static inline bool page_is_guard(struct page *page) { return false; }
#endif /* CONFIG_DEBUG_PAGEALLOC */
+static inline phys_addr_t last_lowmem_phys_addr(void)
+{
+ /*
+ * 'high_memory' is not a pointer that can be dereferenced, so
+ * avoid calling __pa() on it directly.
+ */
+ return __pa(high_memory - 1);
+}
+static inline bool phys_addr_is_highmem(phys_addr_t addr)
+{
+ return addr > last_lowmem_paddr();
+}
+
Are we sure that high_memory - 1 is always a valid reference? Consider
especially the case where there is MMIO beyond end of memory on a system
which has less RAM than the HIGHMEM boundary...
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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