x86/apic/uv: Update the APIC UV OEM check

Optimize the first "SGI" OEM check to return faster if the
system is not an SGI or UV system.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Hedi Berriche <hedi@sgi.com>
Acked-by: Dimitri Sivanich <sivanich@sgi.com>
Link: http://lkml.kernel.org/r/20150409182628.952357922@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 8e9dcfd630e4b539e7936050b7bb1673660ae752..2a739a90010ec813dad19087e064f85b67a8ab2a 100644 (file)
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -146,6 +146,9 @@ static int __init uv_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
        int pnodeid, is_uv1, is_uv2, is_uv3;
 
+       if (strncmp(oem_id, "SGI", 3) != 0)
+               return 0;
+
        is_uv1 = !strcmp(oem_id, "SGI");
        is_uv2 = !strcmp(oem_id, "SGI2");
        is_uv3 = !strncmp(oem_id, "SGI3", 4);   /* there are varieties of UV3 */