block: Add error codes for common PR failures

If a PR operation fails we can return a device-specific error which is
impossible to handle in some cases because we could have a mix of devices
when DM is used, or future users like LIO only knows it's interacting with
a block device so it doesn't know the type.

This patch adds a new pr_status enum so drivers can convert errors to a
common type which can be handled by the caller.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20221122032603.32766-2-michael.christie@oracle.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

License cleanup: add SPDX license identifier to uapi header files with no license

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine the correct license.

By default are files without license information under the default
license of the kernel, which is GPLV2. Marking them GPLV2 would exclude
them from being included in non GPLV2 code, which is obviously not
intended. The user space API headers fall under the syscall exception
which is in the kernels COPYING file:

NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".

otherwise syscall usage would not be possible.

Update the files which contain no license information with an SPDX
license identifier. The chosen identifier is 'GPL-2.0 WITH
Linux-syscall-note' which is the officially assigned identifier for the
Linux syscall exception. SPDX license identifiers are a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

uapi: includes linux/types.h before exporting files

Some files will be exported after a following patch. 0-day tests report the
following warning/error:
./usr/include/linux/bcache.h:8: include of <linux/types.h> is preferred over <asm/types.h>
./usr/include/linux/bcache.h:11: found __[us]{8,16,32,64} type without #include <linux/types.h>
./usr/include/linux/qrtr.h:8: found __[us]{8,16,32,64} type without #include <linux/types.h>
./usr/include/linux/cryptouser.h:39: found __[us]{8,16,32,64} type without #include <linux/types.h>
./usr/include/linux/pr.h:14: found __[us]{8,16,32,64} type without #include <linux/types.h>
./usr/include/linux/btrfs_tree.h:337: found __[us]{8,16,32,64} type without #include <linux/types.h>
./usr/include/rdma/bnxt_re-abi.h:45: found __[us]{8,16,32,64} type without #include <linux/types.h>

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

block: add an API for Persistent Reservations

This commits adds a driver API and ioctls for controlling Persistent
Reservations s/genericly/generically/ at the block layer. Persistent
Reservations are supported by SCSI and NVMe and allow controlling who gets
access to a device in a shared storage setup.

Note that we add a pr_ops structure to struct block_device_operations
instead of adding the members directly to avoid bloating all instances
of devices that will never support Persistent Reservations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>