kernel/linux.git/drivers/net/ethernet/ibm, branch master

ibmveth: Disable GSO for packets with small MSS

2026-04-28T02:07:57+00:00

Some physical adapters on Power systems do not support segmentation offload when the MSS is less than 224 bytes. Attempting to send such packets causes the adapter to freeze, stopping all traffic until manually reset. Implement ndo_features_check to disable GSO for packets with small MSS values. The network stack will perform software segmentation instead. The 224-byte minimum matches ibmvnic commit ("ibmvnic: Enforce stronger sanity checks on GSO packets") which uses the same physical adapters in SEA configurations. The issue occurs specifically when the hardware attempts to perform segmentation (gso_segs > 1) with a small MSS. Single-segment GSO packets (gso_segs == 1) do not trigger the problematic LSO code path and are transmitted normally without segmentation. Add an ndo_features_check callback to disable GSO when MSS < 224 bytes. Also call vlan_features_check() to ensure proper handling of VLAN packets, particularly QinQ (802.1ad) configurations where the hardware parser may not support certain offload features. Validated using iptables to force small MSS values. Without the fix, the adapter freezes. With the fix, packets are segmented in software and transmission succeeds. Comprehensive regression testing completedd (MSS tests, performance, stability). Fixes: 8641dd85799f ("ibmveth: Add support for TSO") Cc: stable@vger.kernel.org Reviewed-by: Brian King Tested-by: Shaik Abdulla Tested-by: Naveed Ahmed Signed-off-by: Mingming Cao Link: https://patch.msgid.link/20260424162917.65725-1-mmc@linux.ibm.com Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2026-02-26T18:23:00+00:00

Cross-merge networking fixes after downstream PR (net-7.0-rc2). Conflicts: tools/testing/selftests/drivers/net/hw/rss_ctx.py 19c3a2a81d2b ("selftests: drv-net: rss: Generate unique ports for RSS context tests") ce5a0f4612db ("selftests: drv-net: rss_ctx: test RSS contexts persist after ifdown/up") include/net/inet_connection_sock.h 858d2a4f67ff6 ("tcp: fix potential race in tcp_v6_syn_recv_sock()") fcd3d039fab69 ("tcp: make tcp_v{4,6}_send_check() static") https://lore.kernel.org/aZ8PSFLzBrEU3I89@sirena.org.uk drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c drivers/net/ethernet/mellanox/mlx5/core/en/xsk/pool.c 69050f8d6d075 ("treewide: Replace kmalloc with kmalloc_obj for non-scalar types") bf4afc53b77ae ("Convert 'alloc_obj' family to use the new default GFP_KERNEL argument") 8a96b9144f18a ("net/mlx5e: Alloc xsk channel param out of mlx5e_open_xsk()") Adjacent changes: net/netfilter/ipvs/ip_vs_ctl.c c59bd9e62e06 ("ipvs: use more counters to avoid service lookups") bf4afc53b77a ("Convert 'alloc_obj' family to use the new default GFP_KERNEL argument") Signed-off-by: Jakub Kicinski

net/ibmveth: fix comment typos in ibmveth.c

2026-02-26T03:23:04+00:00

Correct spelling mistakes in comments: - Fix misspelling of gro_receive - Fix misspelling of Partition Signed-off-by: Abhilekh Deka Reviewed-by: Dave Marquardt Link: https://patch.msgid.link/20260224153601.17534-1-abhindeka@gmail.com Signed-off-by: Jakub Kicinski

Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses

2026-02-22T16:26:33+00:00

Conversion performed via this Coccinelle script: // SPDX-License-Identifier: GPL-2.0-only // Options: --include-headers-for-types --all-includes --include-headers --keep-comments virtual patch @gfp depends on patch && !(file in "tools") && !(file in "samples")@ identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex, kzalloc_obj,kzalloc_objs,kzalloc_flex, kvmalloc_obj,kvmalloc_objs,kvmalloc_flex, kvzalloc_obj,kvzalloc_objs,kvzalloc_flex}; @@ ALLOC(... - , GFP_KERNEL ) $ make coccicheck MODE=patch COCCI=gfp.cocci Build and boot tested x86_64 with Fedora 42's GCC and Clang: Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds

Convert more 'alloc_obj' cases to default GFP_KERNEL arguments

2026-02-22T04:03:00+00:00

This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

ibmvnic: Increase max subcrq indirect entries with fallback

2025-08-26T07:45:50+00:00

POWER8 support a maximum of 16 subcrq indirect descriptor entries per H_SEND_SUB_CRQ_INDIRECT call, while POWER9 and newer hypervisors support up to 128 entries. Increasing the max number of indirect descriptor entries improves batching efficiency and reduces hcall overhead, which enhances throughput under large workload on POWER9+. Currently, ibmvnic driver always uses a fixed number of max indirect descriptor entries (16). send_subcrq_indirect() treats all hypervisor errors the same: - Cleanup and Drop the entire batch of descriptors. - Return an error to the caller. - Rely on TCP/IP retransmissions to recover. - If the hypervisor returns H_PARAMETER (e.g., because 128 entries are not supported on POWER8), the driver will continue to drop batches, resulting in unnecessary packet loss. In this patch: Raise the default maximum indirect entries to 128 to improve ibmvnic batching on morden platform. But also gracefully fall back to 16 entries for Power 8 systems. Since there is no VIO interface to query the hypervisor’s supported limit, vnic handles send_subcrq_indirect() H_PARAMETER errors: - On first H_PARAMETER failure, log the failure context - Reduce max_indirect_entries to 16 and allow the single batch to drop. - Subsequent calls automatically use the correct lower limit, avoiding repeated drops. The goal is to optimizes performance on modern systems while handles falling back for older POWER8 hypervisors. Performance shows 40% improvements with MTU (1500) on largework load. Signed-off-by: Mingming Cao Reviewed-by: Brian King Reviewed-by: Haren Myneni Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250821130215.97960-1-mmc@linux.ibm.com Signed-off-by: Paolo Abeni

ibmveth: Add multi buffers rx replenishment hcall support

2025-07-22T13:08:23+00:00

This patch enables batched RX buffer replenishment in ibmveth by using the new firmware-supported h_add_logical_lan_buffers() hcall to submit up to 8 RX buffers in a single call, instead of repeatedly calling the single-buffer h_add_logical_lan_buffer() hcall. During the probe, with the patch, the driver queries ILLAN attributes to detect IBMVETH_ILLAN_RX_MULTI_BUFF_SUPPORT bit. If the attribute is present, rx_buffers_per_hcall is set to 8, enabling batched replenishment. Otherwise, it defaults to 1, preserving the original upstream behavior with no change in code flow for unsupported systems. The core rx replenish logic remains the same. But when batching is enabled, the driver aggregates up to 8 fully prepared descriptors into a single h_add_logical_lan_buffers() hypercall. If any allocation or DMA mapping fails while preparing a batch, only the successfully prepared buffers are submitted, and the remaining are deferred for the next replenish cycle. If at runtime the firmware stops accepting the batched hcall—e,g, after a Live Partition Migration (LPM) to a host that does not support h_add_logical_lan_buffers(), the hypercall returns H_FUNCTION. In that case, the driver transparently disables batching, resets rx_buffers_per_hcall to 1, and falls back to the single-buffer hcall in next future replenishments to take care of these and future buffers. Test were done on systems with firmware that both supports and does not support the new h_add_logical_lan_buffers hcall. On supported firmware, this reduces hypercall overhead significantly over multiple buffers. SAR measurements showed about a 15% improvement in packet processing rate under moderate RX load, with heavier traffic seeing gains more than 30% Signed-off-by: Mingming Cao Reviewed-by: Brian King Reviewed-by: Haren Myneni Reviewed-by: Dave Marquardt Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250719091356.57252-1-mmc@linux.ibm.com Signed-off-by: Paolo Abeni

ibmvnic: Use ndo_get_stats64 to fix inaccurate SAR reporting

2025-07-18T01:55:44+00:00

VNIC testing on multi-core Power systems showed SAR stats drift and packet rate inconsistencies under load. Implements ndo_get_stats64 to provide safe aggregation of queue-level atomic64 counters into rtnl_link_stats64 for use by tools like 'ip -s', 'ifconfig', and 'sar'. Switch to ndo_get_stats64 to align SAR reporting with the standard kernel interface for retrieving netdev stats. This removes redundant per-adapter stat updates, reduces overhead, eliminates cacheline bouncing from hot path updates, and improves the accuracy of reported packet rates. Signed-off-by: Mingming Cao Reviewed-by: Brian King Reviewed-by: Dave Marquardt Reviewed-by: Simon Horman ---- Changes since v3: link to v3: https://www.spinics.net/lists/netdev/msg1107999.html -- keep per queue counters as u64 (this patch) and drop off patch 1 in v3 Link: https://patch.msgid.link/20250716152115.61143-1-mmc@linux.ibm.com Signed-off-by: Jakub Kicinski