Re: [PATCH] Fix corruption of memmap on IA64 SPARSEMEM when mem_section is not a power of 2

[mel@skynet.ie (Mel Gorman)]

On (25/07/07 15:49), Mel Gorman didst pronounce:
> > SuperH allmodconfig blew up:
> > 
> > mm/sparse.c: In function `sparse_init':
> > mm/sparse.c:482: error: implicit declaration of function `sparse_early_usemap_alloc'
> > mm/sparse.c:482: warning: assignment makes pointer from integer without a cast
> > mm/sparse.c: In function `sparse_add_one_section':
> > mm/sparse.c:553: error: implicit declaration of function `__kmalloc_section_usemap'
> > mm/sparse.c:553: warning: assignment makes pointer from integer without a cast
> 
> This error is due to a bad interaction between
> generic-virtual-memmap-support-for-sparsemem.patch and
> fix-corruption-of-memmap-on-ia64-sparsemem-when-mem_section-is-not-a-power-of-2.patch
> . Functions that are needed whether CONFIG_SPARSEMEM_VMEMMAP is set are
> not are depending on CONFIG_SPARSEMEM_VMEMMAP . This breaks on arch/sh
> for example where SPARSEMEM may be set but not NUMA.
> 

This patch only moves code and does not alter it. However, as SPARSEMEM
is set without NUMA, the code move generates a warning on SuperH because
NODE_DATA(nid) is a no-op. The following patch supresses the warning

Signed-off-by: Mel Gorman <mel@csn.ul.ie>

---
 sparse.c |    3 +++
 1 file changed, 3 insertions(+)

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.23-rc1-mm1-005-sh-sparsemem-fix/mm/sparse.c linux-2.6.23-rc1-mm1-010-sh-sparsemem-fix-warning/mm/sparse.c
--- linux-2.6.23-rc1-mm1-005-sh-sparsemem-fix/mm/sparse.c	2007-07-25 14:27:58.000000000 +0100
+++ linux-2.6.23-rc1-mm1-010-sh-sparsemem-fix-warning/mm/sparse.c	2007-07-25 15:43:07.000000000 +0100
@@ -245,6 +245,9 @@ static unsigned long *sparse_early_usema
 	if (usemap)
 		return usemap;
 
+	/* Stupid: suppress gcc warning for SPARSEMEM && !NUMA */
+	nid = 0;
+
 	printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__);
 	return NULL;
 }