Merge tag 'v6.19-rc1' into msm-next

Merge Linux 6.19-rc1 in order to catch up with other changes (e.g. UBWC
config database defining UBWC_6).

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.q

Merge tag 'v6.19-rc1' into msm-next

Merge Linux 6.19-rc1 in order to catch up with other changes (e.g. UBWC
config database defining UBWC_6).

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

show more ...

Merge drm/drm-next into drm-xe-next

Backmerging to bring in 6.19-rc1. An important upstream bugfix and
to help unblock PTL CI.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Merge drm/drm-next into drm-intel-next

Sync-up some display code needed for Async flips refactor.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge drm/drm-next into drm-misc-next

Let's kickstart the v6.20 (7.0?) release cycle.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge tag 'v6.18' into next

Sync up with the mainline to bring in the latest APIs.

Merge tag 'asoc-fix-v6.19-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v6.19

We've been quite busy with fixes since the merge window, though

Merge tag 'asoc-fix-v6.19-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v6.19

We've been quite busy with fixes since the merge window, though not in
any particularly exciting ways - the standout thing is the fix for _SX
controls which were broken by a change to how we do clamping, otherwise
it's all fairly run of the mill fixes and quirks.

show more ...

Merge remote-tracking branch 'drm/drm-fixes' into drm-misc-fixes

Pull in rc1 to include all changes since the merge window closed,
and grab all fixes and changes from drm/drm-next.

Signed-off-by: M

Merge remote-tracking branch 'drm/drm-fixes' into drm-misc-fixes

Pull in rc1 to include all changes since the merge window closed,
and grab all fixes and changes from drm/drm-next.

Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>

show more ...

Merge tag 'net-next-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:
"Core & protocols:

- Replace busylock at the Tx queuing l

Merge tag 'net-next-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:
"Core & protocols:

- Replace busylock at the Tx queuing layer with a lockless list.

Resulting in a 300% (4x) improvement on heavy TX workloads, sending
twice the number of packets per second, for half the cpu cycles.

- Allow constantly busy flows to migrate to a more suitable CPU/NIC
queue.

Normally we perform queue re-selection when flow comes out of idle,
but under extreme circumstances the flows may be constantly busy.

Add sysctl to allow periodic rehashing even if it'd risk packet
reordering.

- Optimize the NAPI skb cache, make it larger, use it in more paths.

- Attempt returning Tx skbs to the originating CPU (like we already
did for Rx skbs).

- Various data structure layout and prefetch optimizations from Eric.

- Remove ktime_get() from the recvmsg() fast path, ktime_get() is
sadly quite expensive on recent AMD machines.

- Extend threaded NAPI polling to allow the kthread busy poll for
packets.

- Make MPTCP use Rx backlog processing. This lowers the lock
pressure, improving the Rx performance.

- Support memcg accounting of MPTCP socket memory.

- Allow admin to opt sockets out of global protocol memory accounting
(using a sysctl or BPF-based policy). The global limits are a poor
fit for modern container workloads, where limits are imposed using
cgroups.

- Improve heuristics for when to kick off AF_UNIX garbage collection.

- Allow users to control TCP SACK compression, and default to 33% of
RTT.

- Add tcp_rcvbuf_low_rtt sysctl to let datacenter users avoid
unnecessarily aggressive rcvbuf growth and overshot when the
connection RTT is low.

- Preserve skb metadata space across skb_push / skb_pull operations.

- Support for IPIP encapsulation in the nftables flowtable offload.

- Support appending IP interface information to ICMP messages (RFC
5837).

- Support setting max record size in TLS (RFC 8449).

- Remove taking rtnl_lock from RTM_GETNEIGHTBL and RTM_SETNEIGHTBL.

- Use a dedicated lock (and RCU) in MPLS, instead of rtnl_lock.

- Let users configure the number of write buffers in SMC.

- Add new struct sockaddr_unsized for sockaddr of unknown length,
from Kees.

- Some conversions away from the crypto_ahash API, from Eric Biggers.

- Some preparations for slimming down struct page.

- YAML Netlink protocol spec for WireGuard.

- Add a tool on top of YAML Netlink specs/lib for reporting commonly
computed derived statistics and summarized system state.

Driver API:

- Add CAN XL support to the CAN Netlink interface.

- Add uAPI for reporting PHY Mean Square Error (MSE) diagnostics, as
defined by the OPEN Alliance's "Advanced diagnostic features for
100BASE-T1 automotive Ethernet PHYs" specification.

- Add DPLL phase-adjust-gran pin attribute (and implement it in
zl3073x).

- Refactor xfrm_input lock to reduce contention when NIC offloads
IPsec and performs RSS.

- Add info to devlink params whether the current setting is the
default or a user override. Allow resetting back to default.

- Add standard device stats for PSP crypto offload.

- Leverage DSA frame broadcast to implement simple HSR frame
duplication for a lot of switches without dedicated HSR offload.

- Add uAPI defines for 1.6Tbps link modes.

Device drivers:

- Add Motorcomm YT921x gigabit Ethernet switch support.

- Add MUCSE driver for N500/N210 1GbE NIC series.

- Convert drivers to support dedicated ops for timestamping control,
and away from the direct IOCTL handling. While at it support GET
operations for PHY timestamping.

- Add (and convert most drivers to) a dedicated ethtool callback for
reading the Rx ring count.

- Significant refactoring efforts in the STMMAC driver, which
supports Synopsys turn-key MAC IP integrated into a ton of SoCs.

- Ethernet high-speed NICs:
- Broadcom (bnxt):
- support PPS in/out on all pins
- Intel (100G, ice, idpf):
- ice: implement standard ethtool and timestamping stats
- i40e: support setting the max number of MAC addresses per VF
- iavf: support RSS of GTP tunnels for 5G and LTE deployments
- nVidia/Mellanox (mlx5):
- reduce downtime on interface reconfiguration
- disable being an XDP redirect target by default (same as
other drivers) to avoid wasting resources if feature is
unused
- Meta (fbnic):
- add support for Linux-managed PCS on 25G, 50G, and 100G links
- Wangxun:
- support Rx descriptor merge, and Tx head writeback
- support Rx coalescing offload
- support 25G SPF and 40G QSFP modules

- Ethernet virtual:
- Google (gve):
- allow ethtool to configure rx_buf_len
- implement XDP HW RX Timestamping support for DQ descriptor
format
- Microsoft vNIC (mana):
- support HW link state events
- handle hardware recovery events when probing the device

- Ethernet NICs consumer, and embedded:
- usbnet: add support for Byte Queue Limits (BQL)
- AMD (amd-xgbe):
- add device selftests
- NXP (enetc):
- add i.MX94 support
- Broadcom integrated MACs (bcmgenet, bcmasp):
- bcmasp: add support for PHY-based Wake-on-LAN
- Broadcom switches (b53):
- support port isolation
- support BCM5389/97/98 and BCM63XX ARL formats
- Lantiq/MaxLinear switches:
- support bridge FDB entries on the CPU port
- use regmap for register access
- allow user to enable/disable learning
- support Energy Efficient Ethernet
- support configuring RMII clock delays
- add tagging driver for MaxLinear GSW1xx switches
- Synopsys (stmmac):
- support using the HW clock in free running mode
- add Eswin EIC7700 support
- add Rockchip RK3506 support
- add Altera Agilex5 support
- Cadence (macb):
- cleanup and consolidate descriptor and DMA address handling
- add EyeQ5 support
- TI:
- icssg-prueth: support AF_XDP
- Airoha access points:
- add missing Ethernet stats and link state callback
- add AN7583 support
- support out-of-order Tx completion processing
- Power over Ethernet:
- pd692x0: preserve PSE configuration across reboots
- add support for TPS23881B devices

- Ethernet PHYs:
- Open Alliance OATC14 10BASE-T1S PHY cable diagnostic support
- Support 50G SerDes and 100G interfaces in Linux-managed PHYs
- micrel:
- support for non PTP SKUs of lan8814
- enable in-band auto-negotiation on lan8814
- realtek:
- cable testing support on RTL8224
- interrupt support on RTL8221B
- motorcomm: support for PHY LEDs on YT853
- microchip: support for LAN867X Rev.D0 PHYs w/ SQI and cable diag
- mscc: support for PHY LED control

- CAN drivers:
- m_can: add support for optional reset and system wake up
- remove can_change_mtu() obsoleted by core handling
- mcp251xfd: support GPIO controller functionality

- Bluetooth:
- add initial support for PASTa

- WiFi:
- split ieee80211.h file, it's way too big
- improvements in VHT radiotap reporting, S1G, Channel Switch
Announcement handling, rate tracking in mesh networks
- improve multi-radio monitor mode support, and add a cfg80211
debugfs interface for it
- HT action frame handling on 6 GHz
- initial chanctx work towards NAN
- MU-MIMO sniffer improvements

- WiFi drivers:
- RealTek (rtw89):
- support USB devices RTL8852AU and RTL8852CU
- initial work for RTL8922DE
- improved injection support
- Intel:
- iwlwifi: new sniffer API support
- MediaTek (mt76):
- WED support for >32-bit DMA
- airoha NPU support
- regdomain improvements
- continued WiFi7/MLO work
- Qualcomm/Atheros:
- ath10k: factory test support
- ath11k: TX power insertion support
- ath12k: BSS color change support
- ath12k: statistics improvements
- brcmfmac: Acer A1 840 tablet quirk
- rtl8xxxu: 40 MHz connection fixes/support"

* tag 'net-next-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1381 commits)
net: page_pool: sanitise allocation order
net: page pool: xa init with destroy on pp init
net/mlx5e: Support XDP target xmit with dummy program
net/mlx5e: Update XDP features in switch channels
selftests/tc-testing: Test CAKE scheduler when enqueue drops packets
net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop
wireguard: netlink: generate netlink code
wireguard: uapi: generate header with ynl-gen
wireguard: uapi: move flag enums
wireguard: uapi: move enum wg_cmd
wireguard: netlink: add YNL specification
selftests: drv-net: Fix tolerance calculation in devlink_rate_tc_bw.py
selftests: drv-net: Fix and clarify TC bandwidth split in devlink_rate_tc_bw.py
selftests: drv-net: Set shell=True for sysfs writes in devlink_rate_tc_bw.py
selftests: drv-net: Use Iperf3Runner in devlink_rate_tc_bw.py
selftests: drv-net: introduce Iperf3Runner for measurement use cases
selftests: drv-net: Add devlink_rate_tc_bw.py to TEST_PROGS
net: ps3_gelic_net: Use napi_alloc_skb() and napi_gro_receive()
Documentation: net: dsa: mention simple HSR offload helpers
Documentation: net: dsa: mention availability of RedBox
...

show more ...

Merge remote-tracking branch 'drm/drm-next' into msm-next-robclark

Back-merge drm-next to get caught up.

Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>

net: Kconfig: discourage drop_monitor enablement

Quoting Eric Dumazet:
"I do not understand the fascination with net/core/drop_monitor.c [..]
misses all the features, flexibility, scalability that

net: Kconfig: discourage drop_monitor enablement

Quoting Eric Dumazet:
"I do not understand the fascination with net/core/drop_monitor.c [..]
misses all the features, flexibility, scalability that 'perf',
eBPF tracing, bpftrace, .... have today."

Reword DROP_MONITOR kconfig help text to clearly state that its not
related to perf-based drop monitoring and that its safe to disable
this unless support for the older netlink-based tools is needed.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251016115147.18503-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

Merge drm/drm-next into drm-xe-next

Backmerging to bring in 6.18-rc1.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Merge drm/drm-next into drm-intel-next

Sync to v6.18-rc1.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Merge drm/drm-next into drm-misc-next

Updating drm-misc-next to the state of v6.18-rc1.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-intel-gt-next

Backmerge in order to get the commit:

048832a3f400 ("drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter")

To drm-intel-gt-next as there are f

Merge drm/drm-next into drm-intel-gt-next

Backmerge in order to get the commit:

048832a3f400 ("drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter")

To drm-intel-gt-next as there are followup fixes to be applied.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

show more ...

Merge branch 'objtool/core'

Bring in the UDB and objtool data annotations to avoid conflicts while further extending the bug exceptions.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>

Merge commit 'linus' into core/bugs, to resolve conflicts

Resolve conflicts with this commit that was developed in parallel
during the merge window:

8c8efa93db68 ("x86/bug: Add ARCH_WARN_ASM macro

Merge commit 'linus' into core/bugs, to resolve conflicts

Resolve conflicts with this commit that was developed in parallel
during the merge window:

8c8efa93db68 ("x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust")

Conflicts:
arch/riscv/include/asm/bug.h
arch/x86/include/asm/bug.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

show more ...

Merge tag 'v6.18-rc6' into for-linus

Sync up with the mainline to bring in definition of
INPUT_PROP_HAPTIC_TOUCHPAD.

spi: Merge up v6.18-rc1

Ensure my CI has a sensible baseline.

Merge tag 'asoc-fix-v6.18-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v6.18

A moderately large collection of driver specific fixes, plus a f

Merge tag 'asoc-fix-v6.18-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v6.18

A moderately large collection of driver specific fixes, plus a few new
quirks and device IDs. The NAU8821 changes are a little large but more
in mechanical ways than in ways that are complex.

show more ...

Merge drm/drm-fixes into drm-misc-fixes

Updating drm-misc-fixes to the state of v6.18-rc1.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge branch 'next' into for-linus

Prepare input updates for 6.18 merge window.

Merge tag 'v6.17-rc2' into HEAD

Sync up with mainline to bring in changes to include/linux/sprintf.h

Merge tag 'net-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Paolo Abeni:
"Core & protocols:

- Improve drop account scalability on NUM

Merge tag 'net-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Paolo Abeni:
"Core & protocols:

- Improve drop account scalability on NUMA hosts for RAW and UDP
sockets and the backlog, almost doubling the Pps capacity under DoS

- Optimize the UDP RX performance under stress, reducing contention,
revisiting the binary layout of the involved data structs and
implementing NUMA-aware locking. This improves UDP RX performance
by an additional 50%, even more under extreme conditions

- Add support for PSP encryption of TCP connections; this mechanism
has some similarities with IPsec and TLS, but offers superior HW
offloads capabilities

- Ongoing work to support Accurate ECN for TCP. AccECN allows more
than one congestion notification signal per RTT and is a building
block for Low Latency, Low Loss, and Scalable Throughput (L4S)

- Reorganize the TCP socket binary layout for data locality, reducing
the number of touched cachelines in the fastpath

- Refactor skb deferral free to better scale on large multi-NUMA
hosts, this improves TCP and UDP RX performances significantly on
such HW

- Increase the default socket memory buffer limits from 256K to 4M to
better fit modern link speeds

- Improve handling of setups with a large number of nexthop, making
dump operating scaling linearly and avoiding unneeded
synchronize_rcu() on delete

- Improve bridge handling of VLAN FDB, storing a single entry per
bridge instead of one entry per port; this makes the dump order of
magnitude faster on large switches

- Restore IP ID correctly for encapsulated packets at GSO
segmentation time, allowing GRO to merge packets in more scenarios

- Improve netfilter matching performance on large sets

- Improve MPTCP receive path performance by leveraging recently
introduced core infrastructure (skb deferral free) and adopting
recent TCP autotuning changes

- Allow bridges to redirect to a backup port when the bridge port is
administratively down

- Introduce MPTCP 'laminar' endpoint that con be used only once per
connection and simplify common MPTCP setups

- Add RCU safety to dst->dev, closing a lot of possible races

- A significant crypto library API for SCTP, MPTCP and IPv6 SR,
reducing code duplication

- Supports pulling data from an skb frag into the linear area of an
XDP buffer

Things we sprinkled into general kernel code:

- Generate netlink documentation from YAML using an integrated YAML
parser

Driver API:

- Support using IPv6 Flow Label in Rx hash computation and RSS queue
selection

- Introduce API for fetching the DMA device for a given queue,
allowing TCP zerocopy RX on more H/W setups

- Make XDP helpers compatible with unreadable memory, allowing more
easily building DevMem-enabled drivers with a unified XDP/skbs
datapath

- Add a new dedicated ethtool callback enabling drivers to provide
the number of RX rings directly, improving efficiency and clarity
in RX ring queries and RSS configuration

- Introduce a burst period for the health reporter, allowing better
handling of multiple errors due to the same root cause

- Support for DPLL phase offset exponential moving average,
controlling the average smoothing factor

Device drivers:

- Add a new Huawei driver for 3rd gen NIC (hinic3)

- Add a new SpacemiT driver for K1 ethernet MAC

- Add a generic abstraction for shared memory communication
devices (dibps)

- Ethernet high-speed NICs:
- nVidia/Mellanox:
- Use multiple per-queue doorbell, to avoid MMIO contention
issues
- support adjacent functions, allowing them to delegate their
SR-IOV VFs to sibling PFs
- support RSS for IPSec offload
- support exposing raw cycle counters in PTP and mlx5
- support for disabling host PFs.
- Intel (100G, ice, idpf):
- ice: support for SRIOV VFs over an Active-Active link
aggregate
- ice: support for firmware logging via debugfs
- ice: support for Earliest TxTime First (ETF) hardware offload
- idpf: support basic XDP functionalities and XSk
- Broadcom (bnxt):
- support Hyper-V VF ID
- dynamic SRIOV resource allocations for RoCE
- Meta (fbnic):
- support queue API, zero-copy Rx and Tx
- support basic XDP functionalities
- devlink health support for FW crashes and OTP mem corruptions
- expand hardware stats coverage to FEC, PHY, and Pause
- Wangxun:
- support ethtool coalesce options
- support for multiple RSS contexts

- Ethernet virtual:
- Macsec:
- replace custom netlink attribute checks with policy-level
checks
- Bonding:
- support aggregator selection based on port priority
- Microsoft vNIC:
- use page pool fragments for RX buffers instead of full pages
to improve memory efficiency

- Ethernet NICs consumer, and embedded:
- Qualcomm: support Ethernet function for IPQ9574 SoC
- Airoha: implement wlan offloading via NPU
- Freescale
- enetc: add NETC timer PTP driver and add PTP support
- fec: enable the Jumbo frame support for i.MX8QM
- Renesas (R-Car S4):
- support HW offloading for layer 2 switching
- support for RZ/{T2H, N2H} SoCs
- Cadence (macb): support TAPRIO traffic scheduling
- TI:
- support for Gigabit ICSS ethernet SoC (icssm-prueth)
- Synopsys (stmmac): a lot of cleanups

- Ethernet PHYs:
- Support 10g-qxgmi phy-mode for AQR412C, Felix DSA and Lynx PCS
driver
- Support bcm63268 GPHY power control
- Support for Micrel lan8842 PHY and PTP
- Support for Aquantia AQR412 and AQR115

- CAN:
- a large CAN-XL preparation work
- reorganize raw_sock and uniqframe struct to minimize memory
usage
- rcar_canfd: update the CAN-FD handling

- WiFi:
- extended Neighbor Awareness Networking (NAN) support
- S1G channel representation cleanup
- improve S1G support

- WiFi drivers:
- Intel (iwlwifi):
- major refactor and cleanup
- Broadcom (brcm80211):
- support for AP isolation
- RealTek (rtw88/89) rtw88/89:
- preparation work for RTL8922DE support
- MediaTek (mt76):
- HW restart improvements
- MLO support
- Qualcomm/Atheros (ath10k):
- GTK rekey fixes

- Bluetooth drivers:
- btusb: support for several new IDs for MT7925
- btintel: support for BlazarIW core
- btintel_pcie: support for _suspend() / _resume()
- btintel_pcie: support for Scorpious, Panther Lake-H484 IDs"

* tag 'net-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1536 commits)
net: stmmac: Add support for Allwinner A523 GMAC200
dt-bindings: net: sun8i-emac: Add A523 GMAC200 compatible
Revert "Documentation: net: add flow control guide and document ethtool API"
octeontx2-pf: fix bitmap leak
octeontx2-vf: fix bitmap leak
net/mlx5e: Use extack in set rxfh callback
net/mlx5e: Introduce mlx5e_rss_params for RSS configuration
net/mlx5e: Introduce mlx5e_rss_init_params
net/mlx5e: Remove unused mdev param from RSS indir init
net/mlx5: Improve QoS error messages with actual depth values
net/mlx5e: Prevent entering switchdev mode with inconsistent netns
net/mlx5: HWS, Generalize complex matchers
net/mlx5: Improve write-combining test reliability for ARM64 Grace CPUs
selftests/net: add tcp_port_share to .gitignore
Revert "net/mlx5e: Update and set Xon/Xoff upon MTU set"
net: add NUMA awareness to skb_attempt_defer_free()
net: use llist for sd->defer_list
net: make softnet_data.defer_count an atomic
selftests: drv-net: psp: add tests for destroying devices
selftests: drv-net: psp: add test for auto-adjusting TCP MSS
...

show more ...

Merge branch 'dibs-direct-internal-buffer-sharing'

Alexandra Winter says:

====================
dibs - Direct Internal Buffer Sharing

This series introduces a generic abstraction of existing compon

Merge branch 'dibs-direct-internal-buffer-sharing'

Alexandra Winter says:

====================
dibs - Direct Internal Buffer Sharing

This series introduces a generic abstraction of existing components like:
- the s390 specific ISM device (Internal Shared Memory),
- the SMC-D loopback mechanism (Shared Memory Communication - Direct)
- the client interface of the SMC-D module to the transport devices
This generic shim layer can be extended with more devices, more clients and
more features in the future.

This layer is called 'dibs' for Direct Internal Buffer Sharing based on the
common scheme that these mechanisms enable controlled sharing of memory
buffers within some containing entity such as a hypervisor or a Linux
instance.

Benefits:
- Cleaner separation of ISM and SMC-D functionality
- simpler and less module dependencies
- Clear interface definition.
- Extendable for future devices and clients.

An overview was given at the Netdev 0x19 conference, recordings and slides
are available [1].

Background / Status quo:
------------------------
Currently s390 hardware provides virtual PCI ISM devices (Internal Shared
Memory). Their driver is in drivers/s390/net/ism_drv.c. The main user is
SMC-D (net/smc). The ism driver offers a client interface so other
users/protocols can also use them, but it is still heavily intermingled
with the smc code. Namely, the ism module cannot be used without the smc
module, which feels artificial.

There is ongoing work to extend the ISM concept of shared buffers that can
be accessed directly by another instance on the same hardware: [2] proposed
a loopback interface (ism_lo), that can be used on non-s390 architectures
(e.g. between containers or to test SMC-D). A minimal implementation went
upstream with [3]: ism_lo currently is a part of the smc protocol and
rather hidden.

[4] proposed a virtio definition of ism (ism_virtio) that can be used
between kvm guests.

We will shortly send an RFC for an dibs client that uses dibs as transport
for TTY.

Concept:
--------
Create a shim layer in net/dibs that contains common definitions and code
for all dibs devices and all dibs clients. Any device or client module only
needs to depend on this dibs layer module and any device or client code
only needs to include the definitions in include/linux/dibs.h.

The name dibs was chosen to clearly distinguish it from the existing s390
ism devices. And to emphasize that it is not about sharing whole memory
regions with anybody, but dedicating single buffers for another system.

Implementation:
---------------
The end result of this series is: A dibs shim layer with
- One dibs client: smc-d
- Two dibs device drivers: ism and dibs-loopback
- Everything prepared to add more clients and more device drivers.

Patches 1-2 contain some issues that were found along the way. They make
sense on their own, but also enable a better structured dibs series.

There are three components that exist today:
a) smc module (especially SMC-D functionality, which is an ism client today)
b) ism device driver (supports multiple ism clients today)
c) smc-loopback (integrated with smc today)
In order to preserve existing functionality at each step, these are not
moved to dibs layer by component, instead:
- the dibs layer is established in parallel to existing code [patches 3-6]
- then some service functions are moved to the dibs layer [patches 7-12]
- the actual data movement is moved to the dibs layer [patch 13]
- and last event handling is moved to the dibs layer [patch 14]

Future:
-------
Items that are not part of this patchset but can be added later:
- dynamically add or remove dibs_loopback. That will be allow for simple
testing of add_dev()/del_dev()
- handle_irq(): Call clients without interrupt context. e.g using
threaded interrupts. I left this for a follow-on, because it includes
conceptual changes for the smcd receive code.
- Any improvements of locking scopes. I mainly moved some of the the
existing locks to dibs layer. I have the feeling there is room for
improvements.
- The device drivers should not loop through the client array
- dibs_dev_op.*_dmb() functions reveal unnecessary details of the
internal dmb struct to the clients
- Check whether client calls to dibs_dev_ops should be replaced by
interface functions that provide additional value
- Check whether device driver calls to dibs_client_ops should be replaced
by interface functions that provide additional value.

Link: [1] https://netdevconf.info/0x19/sessions/talk/communication-via-internal-shared-memory-ism-time-to-open-up.html
Link: [2] https://lore.kernel.org/netdev/1695568613-125057-1-git-send-email-guwen@linux.alibaba.com/
Link: [3] https://lore.kernel.org/linux-kernel//20240428060738.60843-1-guwen@linux.alibaba.com/
Link: [4] https://groups.oasis-open.org/communities/community-home/digestviewer/viewthread?GroupId=3973&MessageKey=c060ecf9-ea1a-49a2-9827-c92f0e6447b2&CommunityKey=2f26be99-3aa1-48f6-93a5-018dce262226&hlmlt=VT
====================

Link: https://patch.msgid.link/20250918110500.1731261-1-wintera@linux.ibm.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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dibs: Create drivers/dibs

Create the file structure for a 'DIBS - Direct Internal Buffer Sharing'
shim layer that will provide generic functionality and declarations for
dibs device drivers and dibs

dibs: Create drivers/dibs

Create the file structure for a 'DIBS - Direct Internal Buffer Sharing'
shim layer that will provide generic functionality and declarations for
dibs device drivers and dibs clients.

Following patches will add functionality.

Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Link: https://patch.msgid.link/20250918110500.1731261-4-wintera@linux.ibm.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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