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>

2 files changed, 10 insertions, 6 deletions

diff --git a/arch/m32r/kernel/setup.c b/arch/m32r/kernel/setup.c
index d64814385d70..f1f5db0c4084 100644
--- a/arch/m32r/kernel/setup.c
+++ b/arch/m32r/kernel/setup.c
@@ -177,25 +177,28 @@ static unsigned long __init setup_memory(void)
          */
         reserve_bootmem(CONFIG_MEMORY_START + PAGE_SIZE,
                 (PFN_PHYS(start_pfn) + bootmap_size + PAGE_SIZE - 1)
-                - CONFIG_MEMORY_START);
+                - CONFIG_MEMORY_START,
+                BOOTMEM_DEFAULT);
 
         /*
          * reserve physical page 0 - it's a special BIOS page on many boxes,
          * enabling clean reboots, SMP operation, laptop functions.
          */
-        reserve_bootmem(CONFIG_MEMORY_START, PAGE_SIZE);
+        reserve_bootmem(CONFIG_MEMORY_START, PAGE_SIZE, BOOTMEM_DEFAULT);
 
         /*
          * reserve memory hole
          */
 #ifdef CONFIG_MEMHOLE
-        reserve_bootmem(CONFIG_MEMHOLE_START, CONFIG_MEMHOLE_SIZE);
+        reserve_bootmem(CONFIG_MEMHOLE_START, CONFIG_MEMHOLE_SIZE,
+                        BOOTMEM_DEFAULT);
 #endif
 
 #ifdef CONFIG_BLK_DEV_INITRD
         if (LOADER_TYPE && INITRD_START) {
                 if (INITRD_START + INITRD_SIZE <= (max_low_pfn << PAGE_SHIFT)) {
-                        reserve_bootmem(INITRD_START, INITRD_SIZE);
+                        reserve_bootmem(INITRD_START, INITRD_SIZE,
+                                        BOOTMEM_DEFAULT);
                         initrd_start = INITRD_START + PAGE_OFFSET;
                         initrd_end = initrd_start + INITRD_SIZE;
                         printk("initrd:start[%08lx],size[%08lx]\n",
diff --git a/arch/m32r/mm/discontig.c b/arch/m32r/mm/discontig.c
index c7efdb0aefc5..07c1af7dc0e2 100644
--- a/arch/m32r/mm/discontig.c
+++ b/arch/m32r/mm/discontig.c
@@ -91,7 +91,8 @@ unsigned long __init setup_memory(void)
                         PFN_PHYS(mp->pages));
 
                 reserve_bootmem_node(NODE_DATA(nid), PFN_PHYS(mp->start_pfn),
-                        PFN_PHYS(mp->free_pfn - mp->start_pfn) + bootmap_size);
+                        PFN_PHYS(mp->free_pfn - mp->start_pfn) + bootmap_size,
+                        BOOTMEM_DEFAULT);
 
                 if (max_low_pfn < max_pfn)
                         max_low_pfn = max_pfn;
@@ -104,7 +105,7 @@ unsigned long __init setup_memory(void)
         if (LOADER_TYPE && INITRD_START) {
                 if (INITRD_START + INITRD_SIZE <= PFN_PHYS(max_low_pfn)) {
                         reserve_bootmem_node(NODE_DATA(0), INITRD_START,
-                                INITRD_SIZE);
+                                INITRD_SIZE, BOOTMEM_DEFAULT);
                         initrd_start = INITRD_START + PAGE_OFFSET;
                         initrd_end = initrd_start + INITRD_SIZE;
                         printk("initrd:start[%08lx],size[%08lx]\n",