linux.git/include/uapi/linux/blkzoned.h, branch v6.4

treewide: uapi: Replace zero-length arrays with flexible-array members

2022-06-28T19:26:05+00:00

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

-fstrict-flex-arrays=3 is coming and we need to land these changes
to prevent issues like these in the short future:

../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0,
but the source string has length 2 (including NUL byte) [-Wfortify-source]
		strcpy(de3->name, ".");
		^

Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If
this breaks anything, we can use a union with a new member name.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Build-tested-by: kernel test robot 
Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/
Acked-by: Dan Williams  # For ndctl.h
Signed-off-by: Gustavo A. R. Silva

block: fix uapi blkzoned.h comments

2020-10-09T18:47:02+00:00

Update the kdoc comments for struct blk_zone (capacity field description
missing) and for struct blk_zone_report (flags field description
missing).

Signed-off-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Jens Axboe

block: add capacity field to zone descriptors

2020-07-08T14:16:19+00:00

In the zoned storage model, the sectors within a zone are typically all
writeable. With the introduction of the Zoned Namespace (ZNS) Command
Set in the NVM Express organization, the model was extended to have a
specific writeable capacity.

Extend the zone descriptor data structure with a zone capacity field to
indicate to the user how many sectors in a zone are writeable.

Introduce backward compatibility in the zone report ioctl by extending
the zone report header data structure with a flags field to indicate if
the capacity field is available.

Reviewed-by: Jens Axboe 
Reviewed-by: Javier González 
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Himanshu Madhani 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Daniel Wagner 
Signed-off-by: Matias Bjørling 
Signed-off-by: Christoph Hellwig

block: add zone open, close and finish ioctl support

2019-11-07T13:31:50+00:00

Introduce three new ioctl commands BLKOPENZONE, BLKCLOSEZONE and
BLKFINISHZONE to allow applications to control the condition of zones
on a zoned block device through the execution of the REQ_OP_ZONE_OPEN,
REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH operations.

Contains contributions from Matias Bjorling, Hans Holmberg,
Dmitry Fomichev, Keith Busch, Damien Le Moal and Christoph Hellwig.

Reviewed-by: Javier González 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Ajay Joshi 
Signed-off-by: Matias Bjorling 
Signed-off-by: Hans Holmberg 
Signed-off-by: Dmitry Fomichev 
Signed-off-by: Keith Busch 
Signed-off-by: Damien Le Moal 
Signed-off-by: Jens Axboe

uapi: fix ioctl documentation

2019-01-24T18:11:42+00:00

The description of the BLKGETNRZONES zoned block device ioctl was not
added as a comment together with this ioctl definition in commit
65e4e3eee83d7 ("block: Introduce BLKGETNRZONES ioctl"). Add its
description here.

Signed-off-by: Damien Le Moal 
Signed-off-by: Jens Axboe

uapi: linux/blkzoned.h: fix BLKGETZONESZ and BLKGETNRZONES definitions

2018-12-17T02:52:02+00:00

According to the documentation in include/uapi/asm-generic/ioctl.h,
_IOW means userspace is writing and kernel is reading, and
_IOR means userspace is reading and kernel is writing.

In case of these two ioctls, kernel is writing and userspace is reading,
so they have to be _IOR instead of _IOW.

Fixes: 72cd87576d1d8 ("block: Introduce BLKGETZONESZ ioctl")
Fixes: 65e4e3eee83d7 ("block: Introduce BLKGETNRZONES ioctl")
Reviewed-by: Damien Le Moal 
Signed-off-by: Dmitry V. Levin 
Signed-off-by: Jens Axboe

block: Introduce BLKGETNRZONES ioctl

2018-10-25T17:17:40+00:00

Get a zoned block device total number of zones. The device can be a
partition of the whole device. The number of zones is always 0 for
regular block devices.

Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: Introduce BLKGETZONESZ ioctl

2018-10-25T17:17:40+00:00

Get a zoned block device zone size in number of 512 B sectors.
The zone size is always 0 for regular block devices.

Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Damien Le Moal 
Signed-off-by: Jens Axboe

include/uapi/linux/blkzoned.h: Remove a superfluous __packed directive

2018-07-09T15:07:52+00:00

Using the __packed directive for a structure that does not need
it is wrong because it makes gcc generate suboptimal code on some
architectures. Hence remove the __packed directive from the
blk_zone_report structure definition. See also
http://digitalvampire.org/blog/index.php/2006/07/31/why-you-shouldnt-use-__attribute__packed/.

Signed-off-by: Bart Van Assche 
Reviewed-by: Damien Le Moal 
Cc: Matias Bjorling 
Cc: Christoph Hellwig 
Signed-off-by: Jens Axboe

License cleanup: add SPDX license identifier to uapi header files with a license

2017-11-02T10:20:11+00:00

Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be.  This makes it hard for
compliance tools to determine the correct license.

Update these files with an SPDX license identifier.  The identifier was
chosen based on the license information in the file.

GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:

   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".

This exception makes it possible to include GPL headers into non GPL
code, without confusing license compliance tools.

Headers which have either explicit dual licensing or are just licensed
under a non GPL license are updated with the corresponding SPDX
identifier and the GPLv2 with syscall exception identifier.  The format
is:
        ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)

SPDX license identifiers are a legally binding shorthand, which can be
used instead of the full boiler plate text.  The update does not remove
existing license information as this has to be done on a case by case
basis and the copyright holders might have to be consulted. This will
happen in a separate step.

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 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman