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, 5 insertions, 3 deletions

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index e8122447f019..ff5debf5eedd 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -220,12 +220,13 @@ void __init do_init_bootmem(void)
                                      lmb_size_bytes(&lmb.reserved, i) - 1;
                 if (addr < total_lowmem)
                         reserve_bootmem(lmb.reserved.region[i].base,
-                                        lmb_size_bytes(&lmb.reserved, i));
+                                        lmb_size_bytes(&lmb.reserved, i),
+                                        BOOTMEM_DEFAULT);
                 else if (lmb.reserved.region[i].base < total_lowmem) {
                         unsigned long adjusted_size = total_lowmem -
                                       lmb.reserved.region[i].base;
                         reserve_bootmem(lmb.reserved.region[i].base,
-                                        adjusted_size);
+                                        adjusted_size, BOOTMEM_DEFAULT);
                 }
         }
 #else
@@ -234,7 +235,8 @@ void __init do_init_bootmem(void)
         /* reserve the sections we're already using */
         for (i = 0; i < lmb.reserved.cnt; i++)
                 reserve_bootmem(lmb.reserved.region[i].base,
-                                lmb_size_bytes(&lmb.reserved, i));
+                                lmb_size_bytes(&lmb.reserved, i),
+                                BOOTMEM_DEFAULT);
 
 #endif
         /* XXX need to clip this if using highmem? */