Introduce flags for reserve_bootmem()

This patchset adds a flags variable to reserve_bootmem() and uses the
BOOTMEM_EXCLUSIVE flag in crashkernel reservation code to detect collisions
between crashkernel area and already used memory.

This patch:

Change the reserve_bootmem() function to accept a new flag BOOTMEM_EXCLUSIVE.
If that flag is set, the function returns with -EBUSY if the memory already
has been reserved in the past.  This is to avoid conflicts.

Because that code runs before SMP initialisation, there's no race condition
inside reserve_bootmem_core().

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix powerpc build]
Signed-off-by: Bernhard Walle <bwalle@suse.de>
Cc: <linux-arch@vger.kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/sparc/mm/init.c b/arch/sparc/mm/init.c
index a1bef07..b89837a 100644
--- a/arch/sparc/mm/init.c
+++ b/arch/sparc/mm/init.c
@@ -259,7 +259,7 @@
 	if (initrd_start) {
 		/* Reserve the initrd image area. */
 		size = initrd_end - initrd_start;
-		reserve_bootmem(initrd_start, size);
+		reserve_bootmem(initrd_start, size, BOOTMEM_DEFAULT);
 		*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;
 
 		initrd_start = (initrd_start - phys_base) + PAGE_OFFSET;
@@ -268,7 +268,7 @@
 #endif
 	/* Reserve the kernel text/data/bss. */
 	size = (start_pfn << PAGE_SHIFT) - phys_base;
-	reserve_bootmem(phys_base, size);
+	reserve_bootmem(phys_base, size, BOOTMEM_DEFAULT);
 	*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;
 
 	/* Reserve the bootmem map.   We do not account for it
@@ -276,7 +276,7 @@
 	 * in free_all_bootmem.
 	 */
 	size = bootmap_size;
-	reserve_bootmem((bootmap_pfn << PAGE_SHIFT), size);
+	reserve_bootmem((bootmap_pfn << PAGE_SHIFT), size, BOOTMEM_DEFAULT);
 	*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;
 
 	return max_pfn;