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/include/linux/bootmem.h b/include/linux/bootmem.h
index 0365ec9..4e4e340 100644
--- a/include/linux/bootmem.h
+++ b/include/linux/bootmem.h
@@ -60,8 +60,20 @@
unsigned long goal,
unsigned long limit);
+/*
+ * flags for reserve_bootmem (also if CONFIG_HAVE_ARCH_BOOTMEM_NODE,
+ * the architecture-specific code should honor this)
+ */
+#define BOOTMEM_DEFAULT 0
+#define BOOTMEM_EXCLUSIVE (1<<0)
+
#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
-extern void reserve_bootmem(unsigned long addr, unsigned long size);
+/*
+ * If flags is 0, then the return value is always 0 (success). If
+ * flags contains BOOTMEM_EXCLUSIVE, then -EBUSY is returned if the
+ * memory already was reserved.
+ */
+extern int reserve_bootmem(unsigned long addr, unsigned long size, int flags);
#define alloc_bootmem(x) \
__alloc_bootmem(x, SMP_CACHE_BYTES, __pa(MAX_DMA_ADDRESS))
#define alloc_bootmem_low(x) \
@@ -84,7 +96,8 @@
unsigned long endpfn);
extern void reserve_bootmem_node(pg_data_t *pgdat,
unsigned long physaddr,
- unsigned long size);
+ unsigned long size,
+ int flags);
extern void free_bootmem_node(pg_data_t *pgdat,
unsigned long addr,
unsigned long size);