treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scsi_dh: force modular build if SCSI is a module

When the scsi_dh core was moved into the scsi core module,
CONFIG_SCSI_DH became a 'bool' option, and now anything depending on it
can be built-in even when CONFIG_SCSI=m. This of course cannot link
successfully:

drivers/scsi/built-in.o: In function `rdac_init':
scsi_dh_alua.c:(.init.text+0x14): undefined reference to `scsi_register_device_handler'
scsi_dh_alua.c:(.init.text+0x64): undefined reference to `scsi_unregister_device_handler'
drivers/scsi/built-in.o: In function `alua_init':
scsi_dh_alua.c:(.init.text+0xb0): undefined reference to `scsi_register_device_handler'

As a workaround, this adds an extra dependency on CONFIG_SCSI, so
Kconfig can figure out whether built-in is allowed or not.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 086b91d052eb ("scsi_dh: integrate into the core SCSI code")
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi_dh: integrate into the core SCSI code

Stop building scsi_dh as a separate module and integrate it fully into the
core SCSI code with explicit callouts at bus scan time. For now the
callouts are placed at the same point as the old bus notifiers were called,
but in the future we will be able to look at ALUA INQUIRY data earlier on.

Note that this also means that the device handler modules need to be loaded
by the time we scan the bus. The next patches will add support for
autoloading device handlers at bus scan time to make sure they are always
loaded if they are enabled in the kernel config.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

drivers/scsi/device_handler: remove depends on CONFIG_EXPERIMENTAL

The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.

CC: "James E.J. Bottomley" <JBottomley@parallels.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[SCSI] scsi_dh: add generic SPC-3 alua handler

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] scsi_dh: add EMC Clariion device handler

This adds support for EMC Clariions. This patch has the features that
currently exists in mainline and advanced features from Ed's patches.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] scsi_dh: add hp sw device handler

This patch provides the device handler to support the older hp boxes
which cannot be upgraded.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] scsi_dh: add lsi rdac device handler

This patch provides the device handler to support the LSI RDAC SCSI
based storage devices.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

[SCSI] scsi_dh: add infrastructure for SCSI Device Handlers

Some of the storage devices (that can be accessed through multiple paths),
do need some special handling for
1. Activating the passive path of the storage access.
2. Decode and handle the special sense codes returned by the devices.
3. Handle the I/Os being sent to the passive path, especially
during the device probe time.
when accessed through multiple paths.

As of today this special device handling is done at the dm-multipath
layer using dm-handlers. That works well for (1); for (2) to be handled
at dm layer, scsi sense information need to be exported from SCSI to dm-layer,
which is not very attractive; (3) cannot be done at all at the dm layer.

Device handler has been moved to SCSI mainly to handle (2) and (3) properly.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>