x86, UV: Handle missing blade-local memory correctly

UV blades may not have any blade-local memory. Add a field
(nid) to the UV blade structure to indicates whether the node
has local memory. This is needed by the GRU driver (pushed
separately).

Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: linux-mm@kvack.org
LKML-Reference: <20090727143507.GA7006@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/uv/uv_hub.h

@@ -327,6 +327,7 @@ struct uv_blade_info {
 	unsigned short	nr_possible_cpus;
 	unsigned short	nr_online_cpus;
 	unsigned short	pnode;
+	short		memory_nid;
 };
 extern struct uv_blade_info *uv_blade_info;
 extern short *uv_node_to_blade;
@@ -363,6 +364,12 @@ static inline int uv_blade_to_pnode(int bid)
 	return uv_blade_info[bid].pnode;
 }
 
+/* Nid of memory node on blade. -1 if no blade-local memory */
+static inline int uv_blade_to_memory_nid(int bid)
+{
+	return uv_blade_info[bid].memory_nid;
+}
+
 /* Determine the number of possible cpus on a blade */
 static inline int uv_blade_nr_possible_cpus(int bid)
 {

arch/x86/kernel/apic/x2apic_uv_x.c

@@ -591,6 +591,8 @@ void __init uv_system_init(void)
 	bytes = sizeof(struct uv_blade_info) * uv_num_possible_blades();
 	uv_blade_info = kmalloc(bytes, GFP_KERNEL);
 	BUG_ON(!uv_blade_info);
+	for (blade = 0; blade < uv_num_possible_blades(); blade++)
+		uv_blade_info[blade].memory_nid = -1;
 
 	get_lowmem_redirect(&lowmem_redir_base, &lowmem_redir_size);
 
@@ -629,6 +631,9 @@ void __init uv_system_init(void)
 		lcpu = uv_blade_info[blade].nr_possible_cpus;
 		uv_blade_info[blade].nr_possible_cpus++;
 
+		/* Any node on the blade, else will contain -1. */
+		uv_blade_info[blade].memory_nid = nid;
+
 		uv_cpu_hub_info(cpu)->lowmem_remap_base = lowmem_redir_base;
 		uv_cpu_hub_info(cpu)->lowmem_remap_top = lowmem_redir_size;
 		uv_cpu_hub_info(cpu)->m_val = m_val;