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>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index c8939dfddfba..8345c3b12f05 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -189,7 +189,7 @@ contig_initmem_init(unsigned long start_pfn, unsigned long end_pfn)
         bootmap_size = init_bootmem(bootmap >> PAGE_SHIFT, end_pfn);
         e820_register_active_regions(0, start_pfn, end_pfn);
         free_bootmem_with_active_regions(0, end_pfn);
-        reserve_bootmem(bootmap, bootmap_size);
+        reserve_bootmem(bootmap, bootmap_size, BOOTMEM_DEFAULT);
 }
 #endif
 
@@ -238,7 +238,8 @@ static void __init reserve_crashkernel(void)
                                         (unsigned long)(free_mem >> 20));
                         crashk_res.start = crash_base;
                         crashk_res.end   = crash_base + crash_size - 1;
-                        reserve_bootmem(crash_base, crash_size);
+                        reserve_bootmem(crash_base, crash_size,
+                                        BOOTMEM_DEFAULT);
                 } else
                         printk(KERN_INFO "crashkernel reservation failed - "
                                         "you have to specify a base address\n");