Files
ipxe/src/core/null_sanboot.c
Michael Brown 7cfdd769aa [block] Describe all SAN devices via ACPI tables
Describe all SAN devices via ACPI tables such as the iBFT.  For tables
that can describe only a single device (i.e. the aBFT and sBFT), one
table is installed per device.  For multi-device tables (i.e. the
iBFT), all devices are described in a single table.

An underlying SAN device connection may be closed at the time that we
need to construct an ACPI table.  We therefore introduce the concept
of an "ACPI descriptor" which enables the SAN boot code to maintain an
opaque pointer to the underlying object, and an "ACPI model" which can
build tables from a list of such descriptors.  This separates the
lifecycles of ACPI descriptions from the lifecycles of the block
device interfaces, and allows for construction of the ACPI tables even
if the block device interface has been closed.

For a multipath SAN device, iPXE will wait until sufficient
information is available to describe all devices but will not wait for
all paths to connect successfully.  For example: with a multipath
iSCSI boot iPXE will wait until at least one path has become available
and name resolution has completed on all other paths.  We do this
since the iBFT has to include IP addresses rather than DNS names.  We
will commence booting without waiting for the inactive paths to either
become available or close; this avoids unnecessary boot delays.

Note that the Linux kernel will refuse to accept an iBFT with more
than two NIC or target structures.  We therefore describe only the
NICs that are actually required in order to reach the described
targets.  Any iBFT with at most two targets is therefore guaranteed to
describe at most two NICs.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2017-03-28 19:12:48 +03:00

52 lines
1.7 KiB
C

/*
* Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <errno.h>
#include <ipxe/sanboot.h>
static int null_san_hook ( unsigned int drive __unused,
struct uri **uris __unused,
unsigned int count __unused,
unsigned int flags __unused ) {
return -EOPNOTSUPP;
}
static void null_san_unhook ( unsigned int drive __unused ) {
/* Do nothing */
}
static int null_san_boot ( unsigned int drive __unused ) {
return -EOPNOTSUPP;
}
static int null_san_describe ( void ) {
return -EOPNOTSUPP;
}
PROVIDE_SANBOOT ( null, san_hook, null_san_hook );
PROVIDE_SANBOOT ( null, san_unhook, null_san_unhook );
PROVIDE_SANBOOT ( null, san_boot, null_san_boot );
PROVIDE_SANBOOT ( null, san_describe, null_san_describe );