[PATCH v2] efi: dmi: List SMBIOS3 table before SMBIOS table

[Jean Delvare <jdelvare-l3A5Bk7waGM@public.gmane.org>]

The SMBIOS3 table should appear before the SMBIOS table in
/sys/firmware/efi/systab. This allows user-space utilities which
support both to pick the SMBIOS3 table with a single pass on systems
where both are implemented. The SMBIOS3 entry point is more capable
than the SMBIOS entry point so it should be preferred.

This follows the same logic as the ACPI20 table being listed before
the ACPI table.

Signed-off-by: Jean Delvare <jdelvare-l3A5Bk7waGM@public.gmane.org>
Cc: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Leif Lindholm <leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Matt Fleming <matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
Changes since v1:
 * Added a comment explaining why SMBIOS3 must be listed before SMBIOS,
   so that it doesn't get accidentally broken in the future.

 drivers/firmware/efi/efi.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- linux-4.1-rc1.orig/drivers/firmware/efi/efi.c	2015-04-28 16:31:46.614397242 +0200
+++ linux-4.1-rc1/drivers/firmware/efi/efi.c	2015-04-30 15:15:46.414862079 +0200
@@ -85,10 +85,15 @@ static ssize_t systab_show(struct kobjec
 		str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
 	if (efi.acpi != EFI_INVALID_TABLE_ADDR)
 		str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
-	if (efi.smbios != EFI_INVALID_TABLE_ADDR)
-		str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
+	/*
+	 * If both SMBIOS and SMBIOS3 entry points are implemented, the
+	 * SMBIOS3 entry point shall be preferred, so we list it first to
+	 * let applications stop parsing after the first match.
+	 */
 	if (efi.smbios3 != EFI_INVALID_TABLE_ADDR)
 		str += sprintf(str, "SMBIOS3=0x%lx\n", efi.smbios3);
+	if (efi.smbios != EFI_INVALID_TABLE_ADDR)
+		str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
 	if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
 		str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
 	if (efi.boot_info != EFI_INVALID_TABLE_ADDR)


-- 
Jean Delvare
SUSE L3 Support