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/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index c032409..39f3dfe 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -232,7 +232,7 @@
 		goto disable;
 	}
 
-	reserve_bootmem(__pa(initrd_start), size);
+	reserve_bootmem(__pa(initrd_start), size, BOOTMEM_DEFAULT);
 	initrd_below_start_ok = 1;
 
 	printk(KERN_INFO "Initial ramdisk at: 0x%lx (%lu bytes)\n",
@@ -413,7 +413,7 @@
 	/*
 	 * Reserve the bootmap memory.
 	 */
-	reserve_bootmem(PFN_PHYS(mapstart), bootmap_size);
+	reserve_bootmem(PFN_PHYS(mapstart), bootmap_size, BOOTMEM_DEFAULT);
 
 	/*
 	 * Reserve initrd memory if needed.