kernel/linux.git/include/linux/usb/usbnet.h, branch v6.19.11

qmi_wwan: allow max_mtu above hard_mtu to control rx_urb_size

2026-03-19T15:15:25+00:00

commit 55f854dd5bdd8e19b936a00ef1f8d776ac32c7b0 upstream. Commit c7159e960f14 ("usbnet: limit max_mtu based on device's hard_mtu") capped net->max_mtu to the device's hard_mtu in usbnet_probe(). While this correctly prevents oversized packets on standard USB network devices, it breaks the qmi_wwan driver. qmi_wwan relies on userspace (e.g. ModemManager) setting a large MTU on the wwan0 interface to configure rx_urb_size via usbnet_change_mtu(). QMI modems negotiate USB transfer sizes of 16,383 or 32,767 bytes, and the USB receive buffers must be sized accordingly. With max_mtu capped to hard_mtu (~1500 bytes), userspace can no longer raise the MTU, the receive buffers remain small, and download speeds drop from >300 Mbps to ~0.8 Mbps. Introduce a FLAG_NOMAXMTU driver flag that allows individual usbnet drivers to opt out of the max_mtu cap. Set this flag in qmi_wwan's driver_info structures to restore the previous behavior for QMI devices, while keeping the safety fix in place for all other usbnet drivers. Fixes: c7159e960f14 ("usbnet: limit max_mtu based on device's hard_mtu") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/CAPh3n803k8JcBPV5qEzUB-oKzWkAs-D5CU7z=Vd_nLRCr5ZqQg@mail.gmail.com/ Reported-by: Koen Vandeputte Tested-by: Daniele Palmas Signed-off-by: Laurent Vivier Link: https://patch.msgid.link/20260304134338.1785002-1-lvivier@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

usbnet: Add support for Byte Queue Limits (BQL)

2025-11-11T01:28:38+00:00

In the current implementation, usbnet uses a fixed tx_qlen of: USB2: 60 * 1518 bytes = 91.08 KB USB3: 60 * 5 * 1518 bytes = 454.80 KB Such large transmit queues can be problematic, especially for cellular modems. For example, with a typical celluar link speed of 10 Mbit/s, a fully occupied USB3 transmit queue results in: 454.80 KB / (10 Mbit/s / 8 bit/byte) = 363.84 ms of additional latency. This patch adds support for Byte Queue Limits (BQL) [1] to dynamically manage the transmit queue size and reduce latency without sacrificing throughput. Testing was performed on various devices using the usbnet driver for packet transmission: - DELOCK 66045: USB3 to 2.5 GbE adapter (ax88179_178a) - DELOCK 61969: USB2 to 1 GbE adapter (asix) - Quectel RM520: 5G modem (qmi_wwan) - USB2 Android tethering (cdc_ncm) No performance degradation was observed for iperf3 TCP or UDP traffic, while latency for a prioritized ping application was significantly reduced. For example, using the USB3 to 2.5 GbE adapter, which was fully utilized by iperf3 UDP traffic, the prioritized ping was improved from 1.6 ms to 0.6 ms. With the same setup but with a 100 Mbit/s Ethernet connection, the prioritized ping was improved from 35 ms to 5 ms. [1] https://lwn.net/Articles/469652/ Signed-off-by: Simon Schippers Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251106175615.26948-1-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski

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

2025-07-26T18:49:45+00:00

Merge in late fixes to prepare for the 6.17 net-next PR. Conflicts: net/core/neighbour.c 1bbb76a89948 ("neighbour: Fix null-ptr-deref in neigh_flush_dev().") 13a936bb99fb ("neighbour: Protect tbl->phash_buckets[] with a dedicated mutex.") 03dc03fa0432 ("neighbor: Add NTF_EXT_VALIDATED flag for externally validated entries") Adjacent changes: drivers/net/usb/usbnet.c 0d9cfc9b8cb1 ("net: usbnet: Avoid potential RCU stall on LINK_CHANGE event") 2c04d279e857 ("net: usb: Convert tasklet API to new bottom half workqueue mechanism") net/ipv6/route.c 31d7d67ba127 ("ipv6: annotate data-races around rt->fib6_nsiblings") 1caf27297215 ("ipv6: adopt dst_dev() helper") 3b3ccf9ed05e ("net: Remove unnecessary NULL check for lwtunnel_fill_encap()") Signed-off-by: Jakub Kicinski

net: usbnet: Avoid potential RCU stall on LINK_CHANGE event

2025-07-25T18:02:51+00:00

The Gemalto Cinterion PLS83-W modem (cdc_ether) is emitting confusing link up and down events when the WWAN interface is activated on the modem-side. Interrupt URBs will in consecutive polls grab: * Link Connected * Link Disconnected * Link Connected Where the last Connected is then a stable link state. When the system is under load this may cause the unlink_urbs() work in __handle_link_change() to not complete before the next usbnet_link_change() call turns the carrier on again, allowing rx_submit() to queue new SKBs. In that event the URB queue is filled faster than it can drain, ending up in a RCU stall: rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 0-.... } 33108 jiffies s: 201 root: 0x1/. rcu: blocking rcu_node structures (internal RCU debug): Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 Call trace: arch_local_irq_enable+0x4/0x8 local_bh_enable+0x18/0x20 __netdev_alloc_skb+0x18c/0x1cc rx_submit+0x68/0x1f8 [usbnet] rx_alloc_submit+0x4c/0x74 [usbnet] usbnet_bh+0x1d8/0x218 [usbnet] usbnet_bh_tasklet+0x10/0x18 [usbnet] tasklet_action_common+0xa8/0x110 tasklet_action+0x2c/0x34 handle_softirqs+0x2cc/0x3a0 __do_softirq+0x10/0x18 ____do_softirq+0xc/0x14 call_on_irq_stack+0x24/0x34 do_softirq_own_stack+0x18/0x20 __irq_exit_rcu+0xa8/0xb8 irq_exit_rcu+0xc/0x30 el1_interrupt+0x34/0x48 el1h_64_irq_handler+0x14/0x1c el1h_64_irq+0x68/0x6c _raw_spin_unlock_irqrestore+0x38/0x48 xhci_urb_dequeue+0x1ac/0x45c [xhci_hcd] unlink1+0xd4/0xdc [usbcore] usb_hcd_unlink_urb+0x70/0xb0 [usbcore] usb_unlink_urb+0x24/0x44 [usbcore] unlink_urbs.constprop.0.isra.0+0x64/0xa8 [usbnet] __handle_link_change+0x34/0x70 [usbnet] usbnet_deferred_kevent+0x1c0/0x320 [usbnet] process_scheduled_works+0x2d0/0x48c worker_thread+0x150/0x1dc kthread+0xd8/0xe8 ret_from_fork+0x10/0x20 Get around the problem by delaying the carrier on to the scheduled work. This needs a new flag to keep track of the necessary action. The carrier ok check cannot be removed as it remains required for the LINK_RESET event flow. Fixes: 4b49f58fff00 ("usbnet: handle link change") Cc: stable@vger.kernel.org Signed-off-by: John Ernberg Link: https://patch.msgid.link/20250723102526.1305339-1-john.ernberg@actia.se Signed-off-by: Jakub Kicinski

net: usb: Convert tasklet API to new bottom half workqueue mechanism

2025-06-19T22:40:02+00:00

Migrate tasklet APIs to the new bottom half workqueue mechanism. It replaces all occurrences of tasklet usage with the appropriate workqueue APIs throughout the usbnet driver. This transition ensures compatibility with the latest design and enhances performance. Signed-off-by: Jun Miao Link: https://patch.msgid.link/20250618173923.950510-1-jun.miao@intel.com Signed-off-by: Jakub Kicinski

usbnet: fix cyclical race on disconnect with work queue

2024-09-26T08:54:42+00:00

The work can submit URBs and the URBs can schedule the work. This cycle needs to be broken, when a device is to be stopped. Use a flag to do so. This is a design issue as old as the driver. Signed-off-by: Oliver Neukum Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") CC: stable@vger.kernel.org Link: https://patch.msgid.link/20240919123525.688065-1-oneukum@suse.com Signed-off-by: Paolo Abeni

Merge tag 'spdx-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx

2022-08-04T19:12:54+00:00

Pull SPDX updates from Greg KH: "Here is the set of SPDX comment updates for 6.0-rc1. Nothing huge here, just a number of updated SPDX license tags and cleanups based on the review of a number of common patterns in GPLv2 boilerplate text. Also included in here are a few other minor updates, two USB files, and one Documentation file update to get the SPDX lines correct. All of these have been in the linux-next tree for a very long time" * tag 'spdx-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: (28 commits) Documentation: samsung-s3c24xx: Add blank line after SPDX directive x86/crypto: Remove stray comment terminator treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_406.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_398.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_391.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_390.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_385.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_320.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_319.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_318.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_298.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_292.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_179.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_168.RULE (part 2) treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_168.RULE (part 1) treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_160.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_152.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_149.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_147.RULE treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_133.RULE ...

add missing includes and forward declarations to networking includes under linux/

2022-07-28T09:29:36+00:00

Similarly to a recent include/net/ cleanup, this patch adds missing includes to networking headers under include/linux. All these problems are currently masked by the existing users including the missing dependency before the broken header. Link: https://lore.kernel.org/all/20220723045755.2676857-1-kuba@kernel.org/ v1 Signed-off-by: Jakub Kicinski Link: https://lore.kernel.org/r/20220726215652.158167-1-kuba@kernel.org Signed-off-by: Paolo Abeni

USB: Follow-up to SPDX GPL-2.0+ identifiers addition - remove now useless comments

2022-06-10T09:24:37+00:00

All these files have been updated in the commit given in the Fixes: tag below. When the SPDX-License-Identifier: has been added, the corresponding text at the beginning of the files has not been deleted. All these texts are about GPL-2.0+, with different variation in the wording. Remove these now useless lines to save some LoC. Fixes: 5fd54ace4721 ("USB: add SPDX identifiers to all remaining files in drivers/usb/") Signed-off-by: Christophe JAILLET Signed-off-by: Greg Kroah-Hartman

cdc_ether: export usbnet_cdc_zte_rx_fixup

2022-04-14T13:08:12+00:00

Commit bfe9b9d2df66 ("cdc_ether: Improve ZTE MF823/831/910 handling") introduces a workaround for certain ZTE modems reporting invalid MAC addresses over CDC-ECM. The same issue was present on their RNDIS interface,which was fixed in commit a5a18bdf7453 ("rndis_host: Set valid random MAC on buggy devices"). However, internal modem of ZTE MF286R router, on its RNDIS interface, also exhibits a second issue fixed already in CDC-ECM, of the device not respecting configured random MAC address. In order to share the fixup for this with rndis_host driver, export the workaround function, which will be re-used in the following commit in rndis_host. Cc: Kristian Evensen Cc: Bjørn Mork Cc: Oliver Neukum Signed-off-by: Lech Perczak Signed-off-by: Paolo Abeni