From: Thomas Renninger <[email protected]>

mainline inclusion
from mainline-3.6
upstream commit 095adbb6441172985f5ddc3b9e88cb3191bdeac4
category: bugfix

If BIOS provide OS with SRAT table which contains only one disabled
memory affinity structure, this will trigger a WARN_ON.

This patch is based on the former one "ACPI: Untangle a return
statement for better readability".

--------------------------------------------------------

Otherwise you could run into:
WARN_ON in numa_register_memblks(), because node_possible_map is zero

References: https://bugzilla.novell.com/show_bug.cgi?id=757888

On this machine (ProLiant ML570 G3) the SRAT table contains:
  - No processor affinities
  - One memory affinity structure (which is set disabled)

CC: Per Jessen <[email protected]>
CC: Andi Kleen <[email protected]>
Signed-off-by: Thomas Renninger <[email protected]>
Signed-off-by: Len Brown <[email protected]>
Integrated-by: Hanjun Guo <[email protected]>
---
 arch/ia64/kernel/acpi.c |    5 +++--
 arch/x86/mm/srat.c      |   16 +++++++++-------
 drivers/acpi/numa.c     |    8 +++++---
 include/linux/acpi.h    |    2 +-
 4 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 6f38b61..4405788 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -497,7 +497,7 @@ acpi_numa_processor_affinity_init(struct 
acpi_srat_cpu_affinity *pa)
        srat_num_cpus++;
 }
 
-void __init
+int __init
 acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
 {
        unsigned long paddr, size;
@@ -512,7 +512,7 @@ acpi_numa_memory_affinity_init(struct 
acpi_srat_mem_affinity *ma)
 
        /* Ignore disabled entries */
        if (!(ma->flags & ACPI_SRAT_MEM_ENABLED))
-               return;
+               return -1;
 
        /* record this node in proximity bitmap */
        pxm_bit_set(pxm);
@@ -531,6 +531,7 @@ acpi_numa_memory_affinity_init(struct 
acpi_srat_mem_affinity *ma)
        p->size = size;
        p->nid = pxm;
        num_node_memblks++;
+       return 0;
 }
 
 void __init acpi_numa_arch_fixup(void)
diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c
index efb5b4b..db870ec 100644
--- a/arch/x86/mm/srat.c
+++ b/arch/x86/mm/srat.c
@@ -142,23 +142,23 @@ static inline int save_add_info(void) {return 0;}
 #endif
 
 /* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
-void __init
+int __init
 acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
 {
        u64 start, end;
        int node, pxm;
 
        if (srat_disabled())
-               return;
+               return -1;
        if (ma->header.length != sizeof(struct acpi_srat_mem_affinity)) {
                bad_srat();
-               return;
+               return -1;
        }
        if ((ma->flags & ACPI_SRAT_MEM_ENABLED) == 0)
-               return;
+               return -1;
 
        if ((ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) && !save_add_info())
-               return;
+               return -1;
        start = ma->base_address;
        end = start + ma->length;
        pxm = ma->proximity_domain;
@@ -168,16 +168,18 @@ acpi_numa_memory_affinity_init(struct 
acpi_srat_mem_affinity *ma)
        if (node < 0) {
                printk(KERN_ERR "SRAT: Too many proximity domains.\n");
                bad_srat();
-               return;
+               return -1;
        }
 
        if (numa_add_memblk(node, start, end) < 0) {
                bad_srat();
-               return;
+               return -1;
        }
 
        printk(KERN_INFO "SRAT: Node %u PXM %u %Lx-%Lx\n", node, pxm,
               start, end);
+  
+       return 0;
 }
 
 void __init acpi_numa_arch_fixup(void) {}
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 2a63993..cb31298 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -237,6 +237,8 @@ acpi_parse_processor_affinity(struct acpi_subtable_header 
*header,
        return 0;
 }
 
+static int __initdata parsed_numa_memblks;
+
 static int __init
 acpi_parse_memory_affinity(struct acpi_subtable_header * header,
                           const unsigned long end)
@@ -250,8 +252,8 @@ acpi_parse_memory_affinity(struct acpi_subtable_header * 
header,
        acpi_table_print_srat_entry(header);
 
        /* let architecture-dependent part to do it */
-       acpi_numa_memory_affinity_init(memory_affinity);
-
+       if (!acpi_numa_memory_affinity_init(memory_affinity))
+               parsed_numa_memblks++;
        return 0;
 }
 
@@ -306,7 +308,7 @@ int __init acpi_numa_init(void)
 
        if (cnt < 0)
                return cnt;
-       else if (cnt == 0)
+       else if (!parsed_numa_memblks)
                return -ENOENT;
        return 0;
 }
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index f421dd8..8b88441 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -96,7 +96,7 @@ void acpi_table_print_madt_entry (struct acpi_subtable_header 
*madt);
 void acpi_numa_slit_init (struct acpi_table_slit *slit);
 void acpi_numa_processor_affinity_init (struct acpi_srat_cpu_affinity *pa);
 void acpi_numa_x2apic_affinity_init(struct acpi_srat_x2apic_cpu_affinity *pa);
-void acpi_numa_memory_affinity_init (struct acpi_srat_mem_affinity *ma);
+int acpi_numa_memory_affinity_init (struct acpi_srat_mem_affinity *ma);
 void acpi_numa_arch_fixup(void);
 
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
-- 
1.6.0.2


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