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/mm/bootmem.c b/mm/bootmem.c
index 00a9697..f6ff433 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -111,11 +111,12 @@
* might be used for boot-time allocations - or it might get added
* to the free page pool later on.
*/
-static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
- unsigned long size)
+static int __init reserve_bootmem_core(bootmem_data_t *bdata,
+ unsigned long addr, unsigned long size, int flags)
{
unsigned long sidx, eidx;
unsigned long i;
+ int ret;
/*
* round up, partially reserved pages are considered
@@ -133,7 +134,20 @@
#ifdef CONFIG_DEBUG_BOOTMEM
printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
#endif
+ if (flags & BOOTMEM_EXCLUSIVE) {
+ ret = -EBUSY;
+ goto err;
+ }
}
+
+ return 0;
+
+err:
+ /* unreserve memory we accidentally reserved */
+ for (i--; i >= sidx; i--)
+ clear_bit(i, bdata->node_bootmem_map);
+
+ return ret;
}
static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
@@ -374,9 +388,9 @@
}
void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
- unsigned long size)
+ unsigned long size, int flags)
{
- reserve_bootmem_core(pgdat->bdata, physaddr, size);
+ reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
}
void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
@@ -398,9 +412,10 @@
}
#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
-void __init reserve_bootmem(unsigned long addr, unsigned long size)
+int __init reserve_bootmem(unsigned long addr, unsigned long size,
+ int flags)
{
- reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
+ return reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size, flags);
}
#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */