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, 4 insertions, 2 deletions

diff --git a/arch/x86/kernel/mpparse_32.c b/arch/x86/kernel/mpparse_32.c
index 67009cdd5eca..f349e68e45a0 100644
--- a/arch/x86/kernel/mpparse_32.c
+++ b/arch/x86/kernel/mpparse_32.c
@@ -736,7 +736,8 @@ static int __init smp_scan_config (unsigned long base, unsigned long length)
                         smp_found_config = 1;
                         printk(KERN_INFO "found SMP MP-table at [%p] %08lx\n",
                                 mpf, virt_to_phys(mpf));
-                        reserve_bootmem(virt_to_phys(mpf), PAGE_SIZE);
+                        reserve_bootmem(virt_to_phys(mpf), PAGE_SIZE,
+                                        BOOTMEM_DEFAULT);
                         if (mpf->mpf_physptr) {
                                 /*
                                  * We cannot access to MPC table to compute
@@ -751,7 +752,8 @@ static int __init smp_scan_config (unsigned long base, unsigned long length)
                                 unsigned long end = max_low_pfn * PAGE_SIZE;
                                 if (mpf->mpf_physptr + size > end)
                                         size = end - mpf->mpf_physptr;
-                                reserve_bootmem(mpf->mpf_physptr, size);
+                                reserve_bootmem(mpf->mpf_physptr, size,
+                                                BOOTMEM_DEFAULT);
                         }
 
                         mpf_found = mpf;