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Stefan Hajnoczi 5b88af7113 block: allow IOC_PR_READ_* ioctls with BLK_OPEN_READ
The recently added IOC_PR_READ_* ioctls require the same BLK_OPEN_WRITE
permission as the older persistent reservation ioctls. This has the
drawback that udev triggers when the file descriptor is closed,
resulting in unnecessary activity like scanning partitions even though
these read-only ioctls do not modify the device.

Change IOC_PR_READ_KEYS and IOC_PR_READ_RESERVATION to require
BLK_OPEN_READ. This prevents unnecessary activity every time `blkpr
--read-keys` or `blkpr --read-reservation` is invoked by shell scripts,
for example.

It is safe to reduce the permission requirement from BLK_OPEN_WRITE to
BLK_OPEN_READ since these two ioctls do not modify the persistent
reservation state. Userspace cannot use the information fetched by these
ioctls to make changes to the device unless it later opens the device
with BLK_OPEN_WRITE.

Fixes: 3e2cb9ee76 ("block: add IOC_PR_READ_RESERVATION ioctl")
Fixes: 22a1ffea5f ("block: add IOC_PR_READ_KEYS ioctl")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin Wilck <mwilck@suse.com>
Cc: Benjamin Marzinski <bmarzins@redhat.com>
Suggested-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-11 10:36:54 -07:00
arch powerpc updates for 7.0 2026-02-10 21:46:12 -08:00
block block: allow IOC_PR_READ_* ioctls with BLK_OPEN_READ 2026-02-11 10:36:54 -07:00
certs modsign: Enable ML-DSA module signing 2026-02-02 16:57:39 +00:00
crypto Locking updates for v6.20: 2026-02-10 12:28:44 -08:00
Documentation powerpc updates for 7.0 2026-02-10 21:46:12 -08:00
drivers drbd: always set BLK_FEAT_STABLE_WRITES 2026-02-11 10:35:56 -07:00
fs - Extend the resctrl machinery to support telemetry monitoring on Intel. The 2026-02-10 18:24:56 -08:00
include powerpc updates for 7.0 2026-02-10 21:46:12 -08:00
init Scheduler changes for v7.0: 2026-02-10 12:50:10 -08:00
io_uring for-7.0/block-20260206 2026-02-09 17:57:21 -08:00
ipc mqueue: switch to CLASS(filename) 2026-01-16 12:52:04 -05:00
kernel powerpc updates for 7.0 2026-02-10 21:46:12 -08:00
lib Updates for the VDSO subsystem: 2026-02-10 17:02:23 -08:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm Locking updates for v6.20: 2026-02-10 12:28:44 -08:00
net Locking updates for v6.20: 2026-02-10 12:28:44 -08:00
rust Locking updates for v6.20: 2026-02-10 12:28:44 -08:00
samples samples: rust: remove imports available via prelude 2026-01-26 18:15:20 +01:00
scripts asm-generic header updates for 7.0 2026-02-10 20:27:33 -08:00
security powerpc updates for 7.0 2026-02-10 21:46:12 -08:00
sound Updates for the [PCI] MSI subsystem: 2026-02-10 16:30:29 -08:00
tools * VDSO rework and cleanups 2026-02-10 19:34:26 -08:00
usr initramfs: add gen_init_cpio to hostprogs unconditionally 2025-11-26 21:55:40 +01:00
virt Performance events changes for v7.0: 2026-02-10 12:00:46 -08:00
.clang-format s390/pci: Fix cyclic dead-lock in zpci_zdev_put() and zpci_scan_devices() 2025-12-14 11:03:58 +01:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: kbuild: add proc macro library support 2025-11-24 17:15:36 +01:00
.mailmap Rust changes for v6.20 / v7.0 2026-02-10 11:53:01 -08:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS - Remove two drivers for obsolete hardware: i82443bxgx_edac and r82600_edac 2026-02-10 18:14:36 -08:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS powerpc updates for 7.0 2026-02-10 21:46:12 -08:00
Makefile Updates for the VDSO subsystem: 2026-02-10 17:02:23 -08:00
README docs: add AI Coding Assistants documentation 2026-01-06 14:55:06 -07:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros
* AI Coding Assistant - LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst