[tip:x86/apic] x86/apic/uv: Update the APIC UV OEM check

[tip-bot for Mike Travis <tipbot@zytor.com>]

Commit-ID:  7a4e017041136de05527722b97e0c1f8702a5cbe
Gitweb:     http://git.kernel.org/tip/7a4e017041136de05527722b97e0c1f8702a5cbe
Author:     Mike Travis <travis@sgi.com>
AuthorDate: Thu, 9 Apr 2015 13:26:29 -0500
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 10 Apr 2015 10:16:07 +0200

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>
---
 arch/x86/kernel/apic/x2apic_uv_x.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 8e9dcfd..2a739a9 100644
--- 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 */