Re: 2.6.26-rc7: x86 build error

[Johannes Weiner <hannes@saeurebad.de>]

Hi,

Adrian Bunk <bunk@kernel.org> writes:

> Commit d3942cff620bea073fc4e3c8ed878eb1e84615ce
> (x86: use BOOTMEM_EXCLUSIVE on 32-bit)
> causes the following compile error:
>
> <--  snip  -->
>
> ...
>   CC      arch/x86/kernel/setup_32.o
> /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/x86/kernel/setup_32.c: In function ‘reserve_crashkernel’:
> /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/x86/kernel/setup_32.c:536: error: void value not ignored as it ought to be
> make[2]: *** [arch/x86/kernel/setup_32.o] Error 1
>
> <--  snip  -->
>
> CONFIG_KEXEC=y, CONFIG_NEED_MULTIPLE_NODES=y and the fact that 
> reserve_bootmem_node() returns void seems to cause it.

Yes, this triggers it since reserve_bootmem() is then defined to be
reserve_bootmem_node() which returns void while the
!CONFIG_HAVE_ARCH_BOOTMEM_NODE version of reserve_bootmem() in bootmem.c
already returns int.

The following fix is needed:

---

From: Bernhard Walle <bwalle@suse.de>
Subject: Add return value to reserve_bootmem_node()

This patch changes the function reserve_bootmem_node() from void to int,
returning -ENOMEM if the allocation fails.


Signed-off-by: Bernhard Walle <bwalle@suse.de>;

---

Actually, there was a discussion to return -EBUSY instead of -ENOMEM but
in the end it does not matter, because callsites just check for negative
return values.  -hannes

 include/linux/bootmem.h |    2 +-
 mm/bootmem.c            |    6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)
--- a/include/linux/bootmem.h
+++ b/include/linux/bootmem.h
@@ -94,7 +94,7 @@ extern unsigned long init_bootmem_node(p
 				       unsigned long freepfn,
 				       unsigned long startpfn,
 				       unsigned long endpfn);
-extern void reserve_bootmem_node(pg_data_t *pgdat,
+extern int reserve_bootmem_node(pg_data_t *pgdat,
 				 unsigned long physaddr,
 				 unsigned long size,
 				 int flags);
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -442,15 +442,17 @@ unsigned long __init init_bootmem_node(p
 	return init_bootmem_core(pgdat, freepfn, startpfn, endpfn);
 }
 
-void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
+int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 				 unsigned long size, int flags)
 {
 	int ret;
 
 	ret = can_reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
 	if (ret < 0)
-		return;
+		return -ENOMEM;
 	reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
+
+	return 0;
 }
 
 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,