kernel/git/stable/linux.git/drivers/net/ethernet/sfc, branch master

net: add READ_ONCE()/WRITE_ONCE() annotations for dev->num_tc

2026-08-17T17:27:48+00:00

Several fast-path and control-path lockless readers access dev->num_tc (e.g., skb_tx_hash(), netdev_txq_to_tc(), netdev_get_num_tc(), and qdisc/driver lookups) while concurrent writers update dev->num_tc during TC setup, device reset, or channel configuration. Add READ_ONCE() and WRITE_ONCE() annotations to prevent compiler reordering and load/store tearing when accessing dev->num_tc. Update inline helpers in netdevice.h (netdev_get_num_tc(), netdev_set_prio_tc_map(), and netdev_get_sb_channel()) as well as writers and lockless readers in core networking code and drivers. Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260812085440.3917924-3-edumazet@google.com Signed-off-by: Jakub Kicinski

net: prevent torn reads in netdev_tc_txq

2026-08-17T17:27:48+00:00

netdev_set_tc_queue() (and related helpers/drivers such as netdev_bind_sb_channel_queue(), netdev_reset_tc(), and netdev_unbind_sb_channel()) perform separate 16-bit writes to dev->tc_to_txq[tc].count and dev->tc_to_txq[tc].offset. Furthermore, memset() in netdev_reset_tc() and netdev_unbind_sb_channel() provides no guarantee of performing full 32-bit word stores. Concurrent lockless readers (e.g. skb_tx_hash(), netdev_txq_to_tc(), ixgbe_select_queue(), taprio, mqprio, FPE drivers) can observe torn values where offset and count belong to inconsistent configurations. Redefine struct netdev_tc_txq to embed count and offset inside a union with a u32 combined field, allowing atomic manipulation via READ_ONCE() and WRITE_ONCE(). Update all lockless readers and writers across the kernel to use READ_ONCE() and WRITE_ONCE() on the combined field. Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260812085440.3917924-2-edumazet@google.com Signed-off-by: Jakub Kicinski

net: Use helpers to get/set UDP len tree-wide

2026-07-22T11:47:02+00:00

Since BIG TCP for UDP tunnels will start using len=0 in the UDP header as an indicator of a GSO packet bigger than 65535 bytes, this commit introduces the following getter and setters to use tree-wide, in order to explicitly mark places where len=0 may be expected, and handle them properly: 1. udp_set_len() sets uh->len to its real value if it's not bigger than 65535, and to 0 otherwise: to be used in GSO context with aggregated packets. 2. udp_set_len_short() is to be used when the length is known to fit 16 bits. It WARNs when the caller tries to assign a bigger value if CONFIG_DEBUG_NET=y. 3. udp_get_len_short() returns len in host byte order: to be used on the RX side to deal with non-aggregated packets, or to access the raw value of the len field. 4. udp_get_len() decodes uh->len set by udp_set_len(). It checks whether the packet is GSO to guard from malformed packets. At the moment udp_set_len() is not used, a following commit will start using it after enabling len>65535 for GSO. Raw uh->len (in network byte order) is still accessed in a few places for checksum calculation purposes, and to decode len=0 in udpv6_rcv for jumbograms. udp_rcv and udpv6_rcv will be addressed by the commit that starts using udp_set_len() to set UDP len=0 for BIG TCP packets in UDP tunnels. Signed-off-by: Alice Mikityanska Reviewed-by: Willem de Bruijn Acked-by: Jason A. Donenfeld Link: https://patch.msgid.link/20260710134242.216538-2-alice.kernel@fastmail.im Reviewed-by: Nikolay Aleksandrov Signed-off-by: Paolo Abeni

sfc: use kmalloc() to allocate logging buffer

2026-07-08T08:44:43+00:00

efx_mcdi_init() allocates a logging buffer for MCDI firmware communication diagnostics. This buffer can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API that does not require ugly casts and kfree() does not need to know the size of the freed object. Performance difference between kmalloc() and __get_free_pages() is not measurable as both allocators take an object/page from a per-CPU list for fast path allocations. For the slow path the performance is anyway determined by the amount of reclaim involved rather than by what allocator is used. Replace use of __get_free_page() with kmalloc() and free_page() with kfree(). Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Edward Cree Link: https://patch.msgid.link/20260701-b4-drivers-ethernet-v1-4-58776615db6e@kernel.org Signed-off-by: Paolo Abeni

sfc/siena: use kmalloc() to allocate logging buffer

2026-07-08T08:44:43+00:00

efx_siena_mcdi_init() allocates a logging buffer for MCDI firmware communication diagnostics. This buffer can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API that does not require ugly casts and kfree() does not need to know the size of the freed object. Performance difference between kmalloc() and __get_free_pages() is not measurable as both allocators take an object/page from a per-CPU list for fast path allocations. For the slow path the performance is anyway determined by the amount of reclaim involved rather than by what allocator is used. Replace use of __get_free_page() with kmalloc() and free_page() with kfree(). Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Edward Cree Link: https://patch.msgid.link/20260701-b4-drivers-ethernet-v1-3-58776615db6e@kernel.org Signed-off-by: Paolo Abeni

sfc: support pio mapping based on cxl

2026-06-30T22:24:16+00:00

A PIO buffer is a region of device memory to which the driver can write a packet for TX, with the device handling the transmit doorbell without requiring a DMA for getting the packet data, which helps reducing latency in certain exchanges. With CXL mem protocol this latency can be lowered further. With a device supporting CXL and successfully initialised, use the cxl region to map the memory range and use this mapping for PIO buffers. Signed-off-by: Alejandro Lucero Reviewed-by: Dave Jiang Acked-by: Edward Cree Link: https://patch.msgid.link/20260630151346.31201-6-alejandro.lucero-palau@amd.com Signed-off-by: Dave Jiang

sfc: obtain and map cxl range using devm_cxl_probe_mem

2026-06-30T22:24:16+00:00

Use core API for safely obtain the CXL range linked to an HDM committed by the BIOS. Map such a range for being used as the ctpio buffer. A potential user space action through sysfs unbinding or core cxl modules remove will trigger sfc driver device detachment, with that case not racing with this mapping as this is done during driver probe and therefore protected with device lock against those user space actions. Signed-off-by: Alejandro Lucero Reviewed-by: Dave Jiang Acked-by: Edward Cree Signed-off-by: Dan Williams Link: https://patch.msgid.link/20260630151346.31201-5-alejandro.lucero-palau@amd.com Signed-off-by: Dave Jiang

sfc: Initialize cxl dpa

2026-06-30T22:24:16+00:00

Use cxl_set_capacity() for DPA initialization as no mailbox is available. Signed-off-by: Alejandro Lucero Reviewed-by: Dan Williams Reviewed-by: Dave Jiang Reviewed-by: Ben Cheatham Reviewed-by: Jonathan Cameron Acked-by: Edward Cree Link: https://patch.msgid.link/20260630151346.31201-4-alejandro.lucero-palau@amd.com Signed-off-by: Dave Jiang

sfc: Map cxl regs

2026-06-30T22:24:16+00:00

Use cxl core functions for discovering and mapping CXL device registers. Signed-off-by: Alejandro Lucero Reviewed-by: Dan Williams Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Reviewed-by: Ben Cheatham Acked-by: Edward Cree Link: https://patch.msgid.link/20260630151346.31201-3-alejandro.lucero-palau@amd.com Signed-off-by: Dave Jiang

sfc: add cxl support

2026-06-30T22:24:16+00:00

Add CXL initialization based on new CXL API for accel drivers and make it dependent on kernel CXL configuration. Signed-off-by: Alejandro Lucero Reviewed-by: Jonathan Cameron Acked-by: Edward Cree Reviewed-by: Alison Schofield Reviewed-by: Dan Williams Reviewed-by: Dave Jiang Link: https://patch.msgid.link/20260630151346.31201-2-alejandro.lucero-palau@amd.com Signed-off-by: Dave Jiang