Merge tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linuxgrafted

Pull io_uring fixes from Jens Axboe:

 - Fix a task_work add use-after-free with SQPOLL.

   The sqpoll thread could pop and complete the last request while
   io_req_normal_work_add() was still looking at them after the mpscq
   push.

   Use the same approach as DEFER_TASKRUN to protect from that, holding
   an RCU read lock across the add, and have exit wait for an RCU grace
   period for SQPOLL rings as well.

 - CQE32 ring fixes: correct the free entry check for 32b CQEs, zero the
   big_cqe for aux CQEs, and only post the dummy skip CQE on CQE_MIXED
   rings

 - Mark the source filter table as COW when cloning bpf filters, so
   registering another filter on the source doesn't modify the shared
   table in place

 - Initialize the task context before running the BPF loop

 - Requeue zcrx multishot receives stopped by a local resource

 - End a TX_TIMESTAMP multishot cmd when the CQ is full (lollipopkit)

* tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
  io_uring: fix task_work add use-after-free with SQPOLL
  io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full
  io_uring/zcrx: requeue multishot receives stopped by a local resource
  io_uring: initialize task context before running the BPF loop
  io_uring: zero big_cqe for aux CQEs on CQE32 rings
  io_uring: fix free entry check for 32b CQEs on CQE32 rings
  io_uring: only post the dummy skip CQE on CQE_MIXED rings
  io_uring/bpf_filter: mark source as COW when cloning filters

1 files changed, 168 insertions, 0 deletions

diff --git a/Documentation/crypto/libcrypto.rst b/Documentation/crypto/libcrypto.rst
new file mode 100644
index 000000000..e911e0521
--- /dev/null
+++ b/Documentation/crypto/libcrypto.rst
@@ -0,0 +1,168 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+==============
+Crypto library
+==============
+
+The Linux kernel's crypto library (``lib/crypto/``) provides kernel-internal
+users of cryptographic algorithms with faster and easier access to those
+algorithms than the traditional kernel crypto API.
+
+Each cryptographic algorithm is supported via a set of dedicated functions.
+"Crypto agility", where needed, is left to calling code.
+
+The crypto library functions are intended to be boring and straightforward, and
+to follow familiar conventions.  Their primary documentation is their (fairly
+extensive) kernel-doc.  This page just provides some extra high-level context.
+
+Note that the crypto library isn't entirely new.  ``lib/`` has contained some
+crypto functions since 2005.  Rather, it's just an approach that's been expanded
+over time as it's been found to work well.  It also largely just matches how the
+kernel already does things elsewhere.
+
+Scope and intended audience
+===========================
+
+The crypto library documentation is primarily meant for kernel developers who
+need to use a particular cryptographic algorithm(s) in kernel code.  For
+example, "I just need to compute a SHA-256 hash."  A secondary audience is
+developers working on the crypto algorithm implementations themselves.
+
+If you're looking for more general information about cryptography, like the
+differences between the different crypto algorithms or how to select an
+appropriate algorithm, you should refer to external sources which cover that
+type of information much more comprehensively.  If you need help selecting
+algorithms for a new kernel feature that doesn't already have its algorithms
+predefined, please reach out to ``linux-crypto@vger.kernel.org`` for advice.
+
+Code organization
+=================
+
+- ``lib/crypto/*.c``: the crypto algorithm implementations
+
+- ``lib/crypto/$(SRCARCH)/``: architecture-specific code for crypto algorithms.
+  It is here rather than somewhere in ``arch/`` partly because this allows
+  generic and architecture-optimized code to be easily built into a single
+  loadable module (when the algorithm is set to 'm' in the kconfig).
+
+- ``lib/crypto/tests/``: KUnit tests for the crypto algorithms
+
+- ``include/crypto/``: crypto headers, for both the crypto library and the
+  traditional crypto API
+
+Generally, there is one kernel module per algorithm.  Sometimes related
+algorithms are grouped into one module.  There is intentionally no common
+framework, though there are some utility functions that multiple algorithms use.
+
+Each algorithm module is controlled by a tristate kconfig symbol
+``CRYPTO_LIB_$(ALGORITHM)``.  As is the norm for library functions in the
+kernel, these are hidden symbols which don't show up in the kconfig menu.
+Instead, they are just selected by all the kconfig symbols that need them.
+
+Many of the algorithms have multiple implementations: a generic implementation
+and architecture-optimized implementation(s).  Each module initialization
+function, or initcall in the built-in case, automatically enables the best
+implementation based on the available CPU features.
+
+Note that the crypto library doesn't use the ``crypto/``,
+``arch/$(SRCARCH)/crypto/``, or ``drivers/crypto/`` directories.  These
+directories are used by the traditional crypto API.  When possible, algorithms
+in the traditional crypto API are implemented by calls into the library.
+
+Advantages
+==========
+
+Some of the advantages of the library over the traditional crypto API are:
+
+- The library functions tend to be much easier to use.  For example, a hash
+  value can be computed using only a single function call.  Most of the library
+  functions always succeed and return void, eliminating the need to write
+  error-handling code.  Most also accept standard virtual addresses, rather than
+  scatterlists which are difficult and less efficient to work with.
+
+- The library functions are usually faster, especially for short inputs.  They
+  call the crypto algorithms directly without inefficient indirect calls, memory
+  allocations, string parsing, lookups in an algorithm registry, and other
+  unnecessary API overhead.  Architecture-optimized code is enabled by default.
+
+- The library functions use standard link-time dependencies instead of
+  error-prone dynamic loading by name.  There's no need for workarounds such as
+  forcing algorithms to be built-in or adding module soft dependencies.
+
+- The library focuses on the approach that works the best on the vast majority
+  of systems: CPU-based implementations of the crypto algorithms, utilizing
+  on-CPU acceleration (such as AES instructions) when available.
+
+- The library uses standard KUnit tests, rather than custom ad-hoc tests.
+
+- The library tends to have higher assurance implementations of the crypto
+  algorithms.  This is both due to its simpler design and because more of its
+  code is being regularly tested.
+
+- The library supports features that don't fit into the rigid framework of the
+  traditional crypto API, for example interleaved hashing and XOFs.
+
+When to use it
+==============
+
+In-kernel users should use the library (rather than the traditional crypto API)
+whenever possible.  Many subsystems have already been converted.  It usually
+simplifies their code significantly and improves performance.
+
+Some kernel features allow userspace to provide an arbitrary string that selects
+an arbitrary algorithm from the traditional crypto API by name.  These features
+generally will have to keep using the traditional crypto API for backwards
+compatibility.
+
+Note: new kernel features shouldn't support every algorithm, but rather make a
+deliberate choice about what algorithm(s) to support.  History has shown that
+making a deliberate, thoughtful choice greatly simplifies code maintenance,
+reduces the chance for mistakes (such as using an obsolete, insecure, or
+inappropriate algorithm), and makes your feature easier to use.
+
+Testing
+=======
+
+The crypto library uses standard KUnit tests.  Like many of the kernel's other
+KUnit tests, they are included in the set of tests that is run by
+``tools/testing/kunit/kunit.py run --alltests``.
+
+A ``.kunitconfig`` file is also provided to run just the crypto library tests.
+For example, here's how to run them in user-mode Linux:
+
+.. code-block:: sh
+
+    tools/testing/kunit/kunit.py run --kunitconfig=lib/crypto/
+
+Many of the crypto algorithms have architecture-optimized implementations.
+Testing those requires building an appropriate kernel and running the tests
+either in QEMU or on appropriate hardware.  Here's one example with QEMU:
+
+.. code-block:: sh
+
+    tools/testing/kunit/kunit.py run --kunitconfig=lib/crypto/ --arch=arm64 --make_options LLVM=1
+
+Depending on the code being tested, flags may need to be passed to QEMU to
+emulate the correct type of hardware for the code to be reached.
+
+Since correctness is essential in cryptographic code, new architecture-optimized
+code is accepted only if it can be tested in QEMU.
+
+Note: the crypto library also includes FIPS 140 self-tests.  These are
+lightweight, are designed specifically to meet FIPS 140 requirements, and exist
+*only* to meet those requirements.  Normal testing done by kernel developers and
+integrators should use the much more comprehensive KUnit tests instead.
+
+API documentation
+=================
+
+.. toctree::
+   :maxdepth: 2
+
+   libcrypto-auth-encryption
+   libcrypto-blockcipher
+   libcrypto-hash
+   libcrypto-signature
+   libcrypto-unauth-encryption
+   libcrypto-utils
+   sha3