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Robert Beckett 347654387b nvme-pci: 512 byte aligned dma pool segment quirk
[ Upstream commit ebefac5647 ]

We initially introduced a quick fix limiting the queue depth to 1 as
experimentation showed that it fixed data corruption on 64GB steamdecks.

Further experimentation revealed corruption only happens when the last
PRP data element aligns to the end of the page boundary. The device
appears to treat this as a PRP chain to a new list instead of the data
element that it actually is. This implementation is in violation of the
spec. Encountering this errata with the Linux driver requires the host
request a 128k transfer and coincidently be handed the last small pool
dma buffer within a page.

The QD1 quirk effectly works around this because the last data PRP
always was at a 248 byte offset from the page start, so it never
appeared at the end of the page, but comes at the expense of throttling
IO and wasting the remainder of the PRP page beyond 256 bytes. Also to
note, the MDTS on these devices is small enough that the "large" prp
pool can hold enough PRP elements to never reach the end, so that pool
is not a problem either.

Introduce a new quirk to ensure the small pool is always aligned such
that the last PRP element can't appear a the end of the page. This comes
at the expense of wasting 256 bytes per small pool page allocated.

Link: https://lore.kernel.org/linux-nvme/20241113043151.GA20077@lst.de/T/#u
Fixes: 83bdfcbdbe ("nvme-pci: qdepth 1 quirk")
Cc: Paweł Anikiel <panikiel@google.com>
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-01-09 13:31:56 +01:00
arch powerpc: Remove initialisation of readpos 2025-01-09 13:31:55 +01:00
block block: avoid to reuse hctx not removed from cpuhp callback list 2025-01-02 10:32:11 +01:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: ecc - Prevent ecc_digits_from_bytes from reading too many bytes 2025-01-09 13:31:52 +01:00
Documentation ACPI/IORT: Add PMCG platform information for HiSilicon HIP09A 2025-01-09 13:31:51 +01:00
drivers nvme-pci: 512 byte aligned dma pool segment quirk 2025-01-09 13:31:56 +01:00
fs ceph: give up on paths longer than PATH_MAX 2025-01-09 13:31:54 +01:00
include RDMA/mlx5: Enforce same type port association for multiport RoCE 2025-01-09 13:31:56 +01:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-09 10:32:46 +01:00
io_uring io_uring/sqpoll: fix sqpoll error handling races 2025-01-02 10:32:10 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-09 10:32:54 +01:00
kernel tracing: Check "%s" dereference via the field and not the TP_printk format 2025-01-09 13:31:55 +01:00
lib seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str() 2025-01-09 13:31:55 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm memblock: allow zero threshold in validate_numa_converage() 2025-01-09 13:31:40 +01:00
net net: mctp: handle skb cleanup on sock_queue failures 2025-01-09 13:31:54 +01:00
rust rust: macros: fix documentation of the paste! macro 2024-12-09 10:32:25 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 20:00:03 +01:00
scripts setlocalversion: work around "git describe" performance 2024-12-14 20:00:17 +01:00
security selinux: ignore unknown extended permissions 2025-01-09 13:31:54 +01:00
sound ALSA: ump: Shut up truncated string warning 2025-01-09 13:31:53 +01:00
tools stddef: make __struct_group() UAPI C++-friendly 2025-01-02 10:32:03 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock 2024-10-04 16:29:47 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-04 16:29:44 +02:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS membarrier: riscv: Add full memory barrier in switch_mm() 2024-09-12 11:11:45 +02:00
Makefile Linux 6.6.69 2025-01-02 10:32:11 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.