mm: cleanup to make remove_memory() arch-neutral

There is nothing architecture specific about remove_memory().
remove_memory() function is common for all architectures which support
hotplug memory remove. Instead of duplicating it in every architecture,
collapse them into arch neutral function.

[[e-mail]: fix the export]
Signed-off-by: Badari Pulavarty <[e-mail]>
Cc: Yasunori Goto <[e-mail]>
Cc: Gary Hade <[e-mail]>
Cc: Mel Gorman <[e-mail]>
Cc: Yasunori Goto <[e-mail]>
Cc: "Luck, Tony" <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Martin Schwidefsky <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/ia64/mm/init.c

···
 
 	return ret;
 }
-#ifdef CONFIG_MEMORY_HOTREMOVE
-int remove_memory(u64 start, u64 size)
-{
-	unsigned long start_pfn, end_pfn;
-	unsigned long timeout = 120 * HZ;
-	int ret;
-	start_pfn = start >> PAGE_SHIFT;
-	end_pfn = start_pfn + (size >> PAGE_SHIFT);
-	ret = offline_pages(start_pfn, end_pfn, timeout);
-	if (ret)
-		goto out;
-	/* we can free mem_map at this point */
-out:
-	return ret;
-}
-EXPORT_SYMBOL_GPL(remove_memory);
-#endif /* CONFIG_MEMORY_HOTREMOVE */
 #endif
 
 /*

arch/powerpc/mm/mem.c

···
 
 	return __add_pages(zone, start_pfn, nr_pages);
 }
-
-#ifdef CONFIG_MEMORY_HOTREMOVE
-int remove_memory(u64 start, u64 size)
-{
-	unsigned long start_pfn, end_pfn;
-	int ret;
-
-	start_pfn = start >> PAGE_SHIFT;
-	end_pfn = start_pfn + (size >> PAGE_SHIFT);
-	ret = offline_pages(start_pfn, end_pfn, 120 * HZ);
-	if (ret)
-		goto out;
-	/* Arch-specific calls go here - next patch */
-out:
-	return ret;
-}
-#endif /* CONFIG_MEMORY_HOTREMOVE */
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 /*

arch/s390/mm/init.c

···
 	return rc;
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */
-
-#ifdef CONFIG_MEMORY_HOTREMOVE
-int remove_memory(u64 start, u64 size)
-{
-	unsigned long start_pfn, end_pfn;
-
-	start_pfn = PFN_DOWN(start);
-	end_pfn = start_pfn + PFN_DOWN(size);
-	return offline_pages(start_pfn, end_pfn, 120 * HZ);
-}
-#endif /* CONFIG_MEMORY_HOTREMOVE */

mm/memory_hotplug.c

···
 #include <linux/delay.h>
 #include <linux/migrate.h>
 #include <linux/page-isolation.h>
+#include <linux/pfn.h>
 
 #include <asm/tlbflush.h>
 
···
 
 	return ret;
 }
+
+int remove_memory(u64 start, u64 size)
+{
+	unsigned long start_pfn, end_pfn;
+
+	start_pfn = PFN_DOWN(start);
+	end_pfn = start_pfn + PFN_DOWN(size);
+	return offline_pages(start_pfn, end_pfn, 120 * HZ);
+}
 #else
 int remove_memory(u64 start, u64 size)
 {
 	return -EINVAL;
 }
-EXPORT_SYMBOL_GPL(remove_memory);
 #endif /* CONFIG_MEMORY_HOTREMOVE */
+EXPORT_SYMBOL_GPL(remove_memory);