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Chuck Lever 234c0ff695 xprtrdma: Resize reply buffers before reposting receives
Commit 0e13dd9ea8 ("xprtrdma: Remove temp allocation of
rpcrdma_rep objects") made rpcrdma_rep objects survive disconnects.
That is normally fine, but it also means their receive regbufs keep
the size they had when they were first allocated.

Each rep's receive buffer is sized to ep->re_inline_recv when the rep
is created. rpcrdma_ep_create() resets that threshold to the
rdma_max_inline_read ceiling for every new endpoint, and the connect
handshake then shrinks it to the peer's advertised inline send size.
A rep allocated under a smaller negotiated threshold keeps that size:
on disconnect, rpcrdma_xprt_disconnect() drains and DMA-unmaps the
surviving reps but does not free or resize them.

The threshold can come back larger on the next connection. The first
peer may supply no RPC-over-RDMA CM private data, defaulting its send
size to 1024, while the reconnect target is an ordinary server
offering 4096; or, with rdma_max_inline_read raised above its default,
the reconnect target may advertise a larger svcrdma_max_req_size than
the first. rpcrdma_post_recvs() then reposts a surviving rep whose SGE
length is still the old, smaller value, and a larger inline Reply hits
a receive length error and forces another disconnect.

The undersized rep returns to the free list when its failed Receive
flushes, so the following reconnect reposts the same rep and fails the
same way. The transport flaps without making forward progress for as
long as the peer keeps advertising the larger inline size.

This is local/admin-triggerable rather than remote-triggerable: a local
administrator must create and maintain the NFS/RDMA mount, while the
server or reconnect target has to advertise a larger inline send size
and return a reply that uses it.

Fix this by checking each rep before it is reposted. If the receive
regbuf is smaller than the current endpoint's inline receive size,
reallocate it on the current RDMA device's NUMA node and reinitialize
the rep's xdr_buf before DMA-mapping and posting the Receive WR.

Fixes: 0e13dd9ea8 ("xprtrdma: Remove temp allocation of rpcrdma_rep objects")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <anna.schumaker@hammerspace.com>
2026-06-10 15:47:06 -04:00
arch Miscellaneous x86 fixes: 2026-06-07 13:12:29 -07:00
block block-7.1-20260529 2026-05-29 10:41:07 -07:00
certs Clang build fixes for 7.1 2026-04-24 09:29:51 -07:00
crypto crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks 2026-05-20 16:36:45 -07:00
Documentation nfs: remove nfs_compat_user_ino64() and deprecate enable_ino64 2026-06-08 10:21:54 -04:00
drivers regulator: Fix for v7.1 2026-06-07 12:39:36 -07:00
fs NFS: correct CONFIG_NFS_V4 macro name in #endif comment 2026-06-09 14:33:18 -04:00
include nfs: use nfsi->rwsem to protect traversal of the file lock list 2026-06-08 15:04:21 -04:00
init memblock: updates for 7.0-rc1 2026-04-18 11:29:14 -07:00
io_uring io_uring-7.1-20260605 2026-06-05 13:52:15 -07:00
ipc ipc: limit next_id allocation to the valid ID range 2026-05-21 19:06:11 -07:00
kernel Miscellaneous timer fixes: 2026-06-07 13:02:02 -07:00
lib vdso/datastore: Mark vdso_k_*_data pointers as __ro_after_init 2026-06-02 21:39:29 +02:00
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 13 hotfixes. All are for MM. 10 are cc:stable and the remaining 3 2026-06-02 08:59:35 -07:00
net xprtrdma: Resize reply buffers before reposting receives 2026-06-10 15:47:06 -04:00
rust rust: helpers: add is_vmalloc_addr wrapper for NOMMU builds 2026-05-27 20:01:04 +02:00
samples soc: drivers for 7.1 2026-04-16 20:34:34 -07:00
scripts Rust fixes for v7.1 (2nd) 2026-06-06 09:44:42 -07:00
security security/keys: fix missed RCU read section on lookup 2026-05-28 11:45:41 -07:00
sound ALSA: seq: dummy: fix UMP event stack overread 2026-06-05 10:08:57 +02:00
tools vfs-7.1-rc7.fixes 2026-06-06 07:28:59 -07:00
usr kbuild: uapi: also test UAPI headers against C++ compilers 2026-03-25 13:24:42 +01:00
virt KVM: Don't WARN if memory is dirtied without a vCPU when the VM is dying 2026-06-03 16:43:55 +02:00
.clang-format Devicetree updates for v7.0: 2026-02-11 18:27:08 -08:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rust: provide an option to inline C helpers into Rust 2026-03-30 02:03:52 +02:00
.mailmap 13 hotfixes. 9 are for MM. 9 are cc:stable and the remaining 4 address 2026-05-26 08:23:19 -07:00
.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
CREDITS Delete some obsolete networking code 2026-04-24 09:41:58 -07:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS cgroup: Fixes for v7.1-rc6 2026-06-03 08:59:24 -07:00
Makefile Linux 7.1-rc7 2026-06-07 15:37:58 -07:00
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