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path: root/net/core/netpoll.c
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2025-07-07netpoll: move Ethernet setup to push_eth() helperBreno Leitao
Refactor Ethernet header population into dedicated function, completing the layered abstraction with: - push_eth() for link layer - push_udp() for transport - push_ipv4()/push_ipv6() for network Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250702-netpoll_untagle_ip-v2-6-13cf3db24e2b@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-07netpoll: factor out UDP header setup into push_udp() helperBreno Leitao
Move UDP header construction from netpoll_send_udp() into a new static helper function push_udp(). This completes the protocol layer refactoring by: 1. Creating a dedicated helper for UDP header assembly 2. Removing UDP-specific logic from the main send function 3. Establishing a consistent pattern with existing IPv4/IPv6 helpers: - push_udp() - push_ipv4() - push_ipv6() The change improves code organization and maintains the encapsulation pattern established in previous refactorings. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250702-netpoll_untagle_ip-v2-5-13cf3db24e2b@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-07netpoll: factor out IPv4 header setup into push_ipv4() helperBreno Leitao
Move IPv4 header construction from netpoll_send_udp() into a new static helper function push_ipv4(). This completes the refactoring started with IPv6 header handling, creating symmetric helper functions for both IP versions. Changes include: 1. Extracting IPv4 header setup logic into push_ipv4() 2. Replacing inline IPv4 code with helper call 3. Moving eth assignment after helper calls for consistency The refactoring reduces code duplication and improves maintainability by isolating IP version-specific logic. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250702-netpoll_untagle_ip-v2-4-13cf3db24e2b@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-07netpoll: factor out IPv6 header setup into push_ipv6() helperBreno Leitao
Move IPv6 header construction from netpoll_send_udp() into a new static helper function, push_ipv6(). This refactoring reduces code duplication and improves readability in netpoll_send_udp(). Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250702-netpoll_untagle_ip-v2-3-13cf3db24e2b@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-07netpoll: factor out UDP checksum calculation into helperBreno Leitao
Extract UDP checksum calculation logic from netpoll_send_udp() into a new static helper function netpoll_udp_checksum(). This reduces code duplication and improves readability for both IPv4 and IPv6 cases. No functional change intended. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250702-netpoll_untagle_ip-v2-2-13cf3db24e2b@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-07netpoll: Improve code clarity with explicit struct size calculationsBreno Leitao
Replace pointer-dereference sizeof() operations with explicit struct names for improved readability and maintainability. This change: 1. Replaces `sizeof(*udph)` with `sizeof(struct udphdr)` 2. Replaces `sizeof(*ip6h)` with `sizeof(struct ipv6hdr)` 3. Replaces `sizeof(*iph)` with `sizeof(struct iphdr)` This will make it easy to move code in the upcoming patches. No functional changes are introduced by this patch. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250702-netpoll_untagle_ip-v2-1-13cf3db24e2b@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.16-rc4). Conflicts: Documentation/netlink/specs/mptcp_pm.yaml 9e6dd4c256d0 ("netlink: specs: mptcp: replace underscores with dashes in names") ec362192aa9e ("netlink: specs: fix up indentation errors") https://lore.kernel.org/20250626122205.389c2cd4@canb.auug.org.au Adjacent changes: Documentation/netlink/specs/fou.yaml 791a9ed0a40d ("netlink: specs: fou: replace underscores with dashes in names") 880d43ca9aa4 ("netlink: specs: clean up spaces in brackets") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-23net: netpoll: Initialize UDP checksum field before checksummingBreno Leitao
commit f1fce08e63fe ("netpoll: Eliminate redundant assignment") removed the initialization of the UDP checksum, which was wrong and broke netpoll IPv6 transmission due to bad checksumming. udph->check needs to be set before calling csum_ipv6_magic(). Fixes: f1fce08e63fe ("netpoll: Eliminate redundant assignment") Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250620-netpoll_fix-v1-1-f9f0b82bc059@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-19netpoll: Extract IPv6 address retrieval functionBreno Leitao
Extract the IPv6 address retrieval logic from netpoll_setup() into a dedicated helper function netpoll_take_ipv6() to improve code organization and readability. The function handles obtaining the local IPv6 address from the network device, including proper address type matching between local and remote addresses (link-local vs global), and includes appropriate error handling when IPv6 is not supported or no suitable address is available. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250618-netpoll_ip_ref-v1-3-c2ac00fe558f@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-19netpoll: extract IPv4 address retrieval into helper functionBreno Leitao
Move the IPv4 address retrieval logic from netpoll_setup() into a separate netpoll_take_ipv4() function to improve code organization and readability. This change consolidates the IPv4-specific logic and error handling into a dedicated function while maintaining the same functionality. No functional changes. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250618-netpoll_ip_ref-v1-2-c2ac00fe558f@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-19netpoll: Extract carrier wait functionBreno Leitao
Extract the carrier waiting logic into a dedicated helper function netpoll_wait_carrier() to improve code readability and reduce duplication in netpoll_setup(). Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250618-netpoll_ip_ref-v1-1-c2ac00fe558f@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-16netpoll: move netpoll_print_options to netconsoleBreno Leitao
Move netpoll_print_options() from net/core/netpoll.c to drivers/net/netconsole.c and make it static. This function is only used by netconsole, so there's no need to export it or keep it in the public netpoll API. This reduces the netpoll API surface and improves code locality by keeping netconsole-specific functionality within the netconsole driver. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20250613-rework-v3-4-0752bf2e6912@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-16netpoll: relocate netconsole-specific functions to netconsole moduleBreno Leitao
Move netpoll_parse_ip_addr() and netpoll_parse_options() from the generic netpoll module to the netconsole module where they are actually used. These functions were originally placed in netpoll but are only consumed by netconsole. This refactoring improves code organization by: - Removing unnecessary exported symbols from netpoll - Making netpoll_parse_options() static (no longer needs global visibility) - Reducing coupling between netpoll and netconsole modules The functions remain functionally identical - this is purely a code reorganization to better reflect their actual usage patterns. Here are the changes: 1) Move both functions from netpoll to netconsole 2) Add static to netpoll_parse_options() 3) Removed the EXPORT_SYMBOL() PS: This diff does not change the function format, so, it is easy to review, but, checkpatch will not be happy. A follow-up patch will address the current issues reported by checkpatch. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20250613-rework-v3-3-0752bf2e6912@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-16netpoll: expose netpoll logging macros in public headerBreno Leitao
Move np_info(), np_err(), and np_notice() macros from internal implementation to the public netpoll header file to make them available for use by netpoll consumers. These logging macros provide consistent formatting for netpoll-related messages by automatically prefixing log output with the netpoll instance name. The goal is to use the exact same format that is being displayed today, instead of creating something netconsole-specific. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20250613-rework-v3-2-0752bf2e6912@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-16netpoll: remove __netpoll_cleanup from exported APIBreno Leitao
Since commit 97714695ef90 ("net: netconsole: Defer netpoll cleanup to avoid lock release during list traversal"), netconsole no longer uses __netpoll_cleanup(). With no remaining users, remove this function from the exported netpoll API. The function remains available internally within netpoll for use by netpoll_cleanup(). Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20250613-rework-v3-1-0752bf2e6912@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-24netpoll: Eliminate redundant assignmentBreno Leitao
The assignment of zero to udph->check is unnecessary as it is immediately overwritten in the subsequent line. Remove the redundant assignment. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Joe Damato <jdamato@fastly.com> Link: https://patch.msgid.link/20250319-netpoll_nit-v1-1-a7faac5cbd92@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-19netconsole: allow selection of egress interface via MAC addressUday Shankar
Currently, netconsole has two methods of configuration - module parameter and configfs. The former interface allows for netconsole activation earlier during boot (by specifying the module parameter on the kernel command line), so it is preferred for debugging issues which arise before userspace is up/the configfs interface can be used. The module parameter syntax requires specifying the egress interface name. This requirement makes it hard to use for a couple reasons: - The egress interface name can be hard or impossible to predict. For example, installing a new network card in a system can change the interface names assigned by the kernel. - When constructing the module parameter, one may have trouble determining the original (kernel-assigned) name of the interface (which is the name that should be given to netconsole) if some stable interface naming scheme is in effect. A human can usually look at kernel logs to determine the original name, but this is very painful if automation is constructing the parameter. For these reasons, allow selection of the egress interface via MAC address when configuring netconsole using the module parameter. Update the netconsole documentation with an example of the new syntax. Selection of egress interface by MAC address via configfs is far less interesting (since when this interface can be used, one should be able to easily convert between MAC address and interface name), so it is left unimplemented. Signed-off-by: Uday Shankar <ushankar@purestorage.com> Reviewed-by: Breno Leitao <leitao@debian.org> Tested-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250312-netconsole-v6-2-3437933e79b8@purestorage.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-03-13Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netPaolo Abeni
Cross-merge networking fixes after downstream PR (net-6.14-rc6). Conflicts: tools/testing/selftests/drivers/net/ping.py 75cc19c8ff89 ("selftests: drv-net: add xdp cases for ping.py") de94e8697405 ("selftests: drv-net: store addresses in dict indexed by ipver") https://lore.kernel.org/netdev/20250311115758.17a1d414@canb.auug.org.au/ net/core/devmem.c a70f891e0fa0 ("net: devmem: do not WARN conditionally after netdev_rx_queue_restart()") 1d22d3060b9b ("net: drop rtnl_lock for queue_mgmt operations") https://lore.kernel.org/netdev/20250313114929.43744df1@canb.auug.org.au/ Adjacent changes: tools/testing/selftests/net/Makefile 6f50175ccad4 ("selftests: Add IPv6 link-local address generation tests for GRE devices.") 2e5584e0f913 ("selftests/net: expand cmsg_ipv6.sh with ipv4") drivers/net/ethernet/broadcom/bnxt/bnxt.c 661958552eda ("eth: bnxt: do not use BNXT_VNIC_NTUPLE unconditionally in queue restart logic") fe96d717d38e ("bnxt_en: Extend queue stop/start for TX rings") Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-03-07netpoll: hold rcu read lock in __netpoll_send_skb()Breno Leitao
The function __netpoll_send_skb() is being invoked without holding the RCU read lock. This oversight triggers a warning message when CONFIG_PROVE_RCU_LIST is enabled: net/core/netpoll.c:330 suspicious rcu_dereference_check() usage! netpoll_send_skb netpoll_send_udp write_ext_msg console_flush_all console_unlock vprintk_emit To prevent npinfo from disappearing unexpectedly, ensure that __netpoll_send_skb() is protected with the RCU read lock. Fixes: 2899656b494dcd1 ("netpoll: take rcu_read_lock_bh() in netpoll_send_skb_on_dev()") Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250306-netpoll_rcu_v2-v2-1-bc4f5c51742a@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-07netpoll: Optimize skb refilling on critical pathBreno Leitao
netpoll tries to refill the skb queue on every packet send, independently if packets are being consumed from the pool or not. This was particularly problematic while being called from printk(), where the operation would be done while holding the console lock. Introduce a more intelligent approach to skb queue management. Instead of constantly attempting to refill the queue, the system now defers refilling to a work queue and only triggers the workqueue when a buffer is actually dequeued. This change significantly reduces operations with the lock held. Add a work_struct to the netpoll structure for asynchronous refilling, updating find_skb() to schedule refill work only when necessary (skb is dequeued). These changes have demonstrated a 15% reduction in time spent during netpoll_send_msg operations, especially when no SKBs are not consumed from consumed from pool. When SKBs are being dequeued, the improvement is even better, around 70%, mainly because refilling the SKB pool is now happening outside of the critical patch (with console_owner lock held). Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250304-netpoll_refill_v2-v1-1-06e2916a4642@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.13-rc8). Conflicts: drivers/net/ethernet/realtek/r8169_main.c 1f691a1fc4be ("r8169: remove redundant hwmon support") 152d00a91396 ("r8169: simplify setting hwmon attribute visibility") https://lore.kernel.org/20250115122152.760b4e8d@canb.auug.org.au Adjacent changes: drivers/net/ethernet/broadcom/bnxt/bnxt.c 152f4da05aee ("bnxt_en: add support for rx-copybreak ethtool command") f0aa6a37a3db ("eth: bnxt: always recalculate features after XDP clearing, fix null-deref") drivers/net/ethernet/intel/ice/ice_type.h 50327223a8bb ("ice: add lock to protect low latency interface") dc26548d729e ("ice: Fix quad registers read on E825") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-14net: netpoll: ensure skb_pool list is always initializedJohn Sperbeck
When __netpoll_setup() is called directly, instead of through netpoll_setup(), the np->skb_pool list head isn't initialized. If skb_pool_flush() is later called, then we hit a NULL pointer in skb_queue_purge_reason(). This can be seen with this repro, when CONFIG_NETCONSOLE is enabled as a module: ip tuntap add mode tap tap0 ip link add name br0 type bridge ip link set dev tap0 master br0 modprobe netconsole netconsole=4444@10.0.0.1/br0,9353@10.0.0.2/ rmmod netconsole The backtrace is: BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page ... ... ... Call Trace: <TASK> __netpoll_free+0xa5/0xf0 br_netpoll_cleanup+0x43/0x50 [bridge] do_netpoll_cleanup+0x43/0xc0 netconsole_netdev_event+0x1e3/0x300 [netconsole] unregister_netdevice_notifier+0xd9/0x150 cleanup_module+0x45/0x920 [netconsole] __se_sys_delete_module+0x205/0x290 do_syscall_64+0x70/0x150 entry_SYSCALL_64_after_hwframe+0x76/0x7e Move the skb_pool list setup and initial skb fill into __netpoll_setup(). Fixes: 221a9c1df790 ("net: netpoll: Individualize the skb pool") Signed-off-by: John Sperbeck <jsperbeck@google.com> Reviewed-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20250114011354.2096812-1-jsperbeck@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-04netpoll: Make netpoll_send_udp return status instead of voidMaksym Kutsevol
netpoll_send_udp can return if send was successful. It will allow client code to be aware of the send status. Possible return values are the result of __netpoll_send_skb (cast to int) and -ENOMEM. This doesn't cover the case when TX was not successful instantaneously and was scheduled for later, __netpoll__send_skb returns success in that case. Signed-off-by: Maksym Kutsevol <max@kutsevol.com> Link: https://patch.msgid.link/20241202-netcons-add-udp-send-fail-statistics-to-netconsole-v5-1-70e82239f922@kutsevol.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-04netpoll: Use rtnl_dereference() for npinfo pointer accessBreno Leitao
In the __netpoll_setup() function, when accessing the device's npinfo pointer, replace rcu_access_pointer() with rtnl_dereference(). This change is more appropriate, as suggested by Herbert Xu[1]. The function is called with the RTNL mutex held, and the pointer is being dereferenced later, so, dereference earlier and just reuse the pointer for the if/else. The replacement ensures correct pointer access while maintaining the existing locking and RCU semantics of the netpoll subsystem. Link: https://lore.kernel.org/lkml/Zz1cKZYt1e7elibV@gondor.apana.org.au/ [1] Suggested-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Link: https://patch.msgid.link/20241202-netpoll_rcu_herbet_fix-v2-1-2b9d58edc76a@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netPaolo Abeni
Merge in late fixes to prepare for the 6.13 net-next PR. Conflicts: include/linux/phy.h 41ffcd95015f net: phy: fix phylib's dual eee_enabled 721aa69e708b net: phy: convert eee_broken_modes to a linkmode bitmap https://lore.kernel.org/all/20241118135512.1039208b@canb.auug.org.au/ drivers/net/ethernet/wangxun/txgbe/txgbe_phy.c 2160428bcb20 net: txgbe: fix null pointer to pcs 2160428bcb20 net: txgbe: remove GPIO interrupt controller Adjacent commits: include/linux/phy.h 41ffcd95015f net: phy: fix phylib's dual eee_enabled 516a5f11eb97 net: phy: respect cached advertising when re-enabling EEE Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-11-18netpoll: Use rcu_access_pointer() in __netpoll_setupBreno Leitao
The ndev->npinfo pointer in __netpoll_setup() is RCU-protected but is being accessed directly for a NULL check. While no RCU read lock is held in this context, we should still use proper RCU primitives for consistency and correctness. Replace the direct NULL check with rcu_access_pointer(), which is the appropriate primitive when only checking for NULL without dereferencing the pointer. This function provides the necessary ordering guarantees without requiring RCU read-side protection. Reviewed-by: Michal Kubiak <michal.kubiak@intel.com> Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20241118-netpoll_rcu-v1-1-a1888dcb4a02@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-15net: netpoll: flush skb pool during cleanupBreno Leitao
The netpoll subsystem maintains a pool of 32 pre-allocated SKBs per instance, but these SKBs are not freed when the netpoll user is brought down. This leads to memory waste as these buffers remain allocated but unused. Add skb_pool_flush() to properly clean up these SKBs when netconsole is terminated, improving memory efficiency. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20241114-skb_buffers_v2-v3-2-9be9f52a8b69@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-15net: netpoll: Individualize the skb poolBreno Leitao
The current implementation of the netpoll system uses a global skb pool, which can lead to inefficient memory usage and waste when targets are disabled or no longer in use. This can result in a significant amount of memory being unnecessarily allocated and retained, potentially causing performance issues and limiting the availability of resources for other system components. Modify the netpoll system to assign a skb pool to each target instead of using a global one. This approach allows for more fine-grained control over memory allocation and deallocation, ensuring that resources are only allocated and retained as needed. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20241114-skb_buffers_v2-v3-1-9be9f52a8b69@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-23netpoll: remove ndo_netpoll_setup() second argumentEric Dumazet
npinfo is not used in any of the ndo_netpoll_setup() methods. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20241018052108.2610827-1-edumazet@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-10-02move asm/unaligned.h to linux/unaligned.hAl Viro
asm/unaligned.h is always an include of asm-generic/unaligned.h; might as well move that thing to linux/unaligned.h and include that - there's nothing arch-specific in that header. auto-generated by the following: for i in `git grep -l -w asm/unaligned.h`; do sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i done for i in `git grep -l -w asm-generic/unaligned.h`; do sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i done git mv include/asm-generic/unaligned.h include/linux/unaligned.h git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h
2024-09-06netpoll: remove netpoll_srcuEric Dumazet
netpoll_srcu is currently used from netpoll_poll_disable() and __netpoll_cleanup() Both functions run under RTNL, using netpoll_srcu adds confusion and no additional protection. Moreover the synchronize_srcu() call in __netpoll_cleanup() is performed before clearing np->dev->npinfo, which violates RCU rules. After this patch, netpoll_poll_disable() and netpoll_poll_enable() simply use rtnl_dereference(). This saves a big chunk of memory (more than 192KB on platforms with 512 cpus) Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20240905084909.2082486-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-26net: Correct spelling in net/coreSimon Horman
Correct spelling in net/core. As reported by codespell. Signed-off-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20240822-net-spell-v1-13-3a98971ce2d2@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-26netpoll: Ensure clean state on setup failuresBreno Leitao
Modify netpoll_setup() and __netpoll_setup() to ensure that the netpoll structure (np) is left in a clean state if setup fails for any reason. This prevents carrying over misconfigured fields in case of partial setup success. Key changes: - np->dev is now set only after successful setup, ensuring it's always NULL if netpoll is not configured or if netpoll_setup() fails. - np->local_ip is zeroed if netpoll setup doesn't complete successfully. - Added DEBUG_NET_WARN_ON_ONCE() checks to catch unexpected states. - Reordered some operations in __netpoll_setup() for better logical flow. These changes improve the reliability of netpoll configuration, since it assures that the structure is fully initialized or totally unset. Suggested-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://patch.msgid.link/20240822111051.179850-2-leitao@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR. No conflicts. Adjacent changes: drivers/net/ethernet/broadcom/bnxt/bnxt.h c948c0973df5 ("bnxt_en: Don't clear ntuple filters and rss contexts during ethtool ops") f2878cdeb754 ("bnxt_en: Add support to call FW to update a VNIC") Link: https://patch.msgid.link/20240822210125.1542769-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-21netpoll: do not export netpoll_poll_[disable|enable]()Eric Dumazet
netpoll_poll_disable() and netpoll_poll_enable() are only used from core networking code, there is no need to export them. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20240820162053.3870927-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-13net: netpoll: extract core of netpoll_cleanupBreno Leitao
Extract the core part of netpoll_cleanup(), so, it could be called from a caller that has the rtnl lock already. Netconsole uses this in a weird way right now: __netpoll_cleanup(&nt->np); spin_lock_irqsave(&target_list_lock, flags); netdev_put(nt->np.dev, &nt->np.dev_tracker); nt->np.dev = NULL; nt->enabled = false; This will be replaced by do_netpoll_cleanup() as the locking situation is overhauled. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Rik van Riel <riel@surriel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-04-30netpoll: Fix race condition in netpoll_owner_activeBreno Leitao
KCSAN detected a race condition in netpoll: BUG: KCSAN: data-race in net_rx_action / netpoll_send_skb write (marked) to 0xffff8881164168b0 of 4 bytes by interrupt on cpu 10: net_rx_action (./include/linux/netpoll.h:90 net/core/dev.c:6712 net/core/dev.c:6822) <snip> read to 0xffff8881164168b0 of 4 bytes by task 1 on cpu 2: netpoll_send_skb (net/core/netpoll.c:319 net/core/netpoll.c:345 net/core/netpoll.c:393) netpoll_send_udp (net/core/netpoll.c:?) <snip> value changed: 0x0000000a -> 0xffffffff This happens because netpoll_owner_active() needs to check if the current CPU is the owner of the lock, touching napi->poll_owner non atomically. The ->poll_owner field contains the current CPU holding the lock. Use an atomic read to check if the poll owner is the current CPU. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://lore.kernel.org/r/20240429100437.3487432-1-leitao@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-15netpoll: allocate netdev tracker right awayJakub Kicinski
Commit 5fa5ae605821 ("netpoll: add net device refcount tracker to struct netpoll") was part of one of the initial netdev tracker introduction patches. It added an explicit netdev_tracker_alloc() for netpoll, presumably because the flow of the function is somewhat odd. After most of the core networking stack was converted to use the tracking hold() variants, netpoll's call to old dev_hold() stands out a bit. np is allocated by the caller and ready to use, we can use netdev_hold() here, even tho np->ndev will only be set to ndev inside __netpoll_setup(). Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-04-02net: don't let netpoll invoke NAPI if in xmit contextJakub Kicinski
Commit 0db3dc73f7a3 ("[NETPOLL]: tx lock deadlock fix") narrowed down the region under netif_tx_trylock() inside netpoll_send_skb(). (At that point in time netif_tx_trylock() would lock all queues of the device.) Taking the tx lock was problematic because driver's cleanup method may take the same lock. So the change made us hold the xmit lock only around xmit, and expected the driver to take care of locking within ->ndo_poll_controller(). Unfortunately this only works if netpoll isn't itself called with the xmit lock already held. Netpoll code is careful and uses trylock(). The drivers, however, may be using plain lock(). Printing while holding the xmit lock is going to result in rare deadlocks. Luckily we record the xmit lock owners, so we can scan all the queues, the same way we scan NAPI owners. If any of the xmit locks is held by the local CPU we better not attempt any polling. It would be nice if we could narrow down the check to only the NAPIs and the queue we're trying to use. I don't see a way to do that now. Reported-by: Roman Gushchin <roman.gushchin@linux.dev> Fixes: 0db3dc73f7a3 ("[NETPOLL]: tx lock deadlock fix") Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-01-27netpoll: Remove 4s sleep during carrier detectionBreno Leitao
This patch removes the msleep(4s) during netpoll_setup() if the carrier appears instantly. Here are some scenarios where this workaround is counter-productive in modern ages: Servers which have BMC communicating over NC-SI via the same NIC as gets used for netconsole. BMC will keep the PHY up, hence the carrier appearing instantly. The link is fibre, SERDES getting sync could happen within 0.1Hz, and the carrier also appears instantly. Other than that, if a driver is reporting instant carrier and then losing it, this is probably a driver bug. Reported-by: Michael van der Westhuizen <rmikey@meta.com> Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://lore.kernel.org/r/20230125185230.3574681-1-leitao@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-22net: move from strlcpy with unused retval to strscpyWolfram Sang
Follow the advice of the below link and prefer 'strscpy' in this subsystem. Conversion is 1:1 because the return value is not used. Generated by a coccinelle script. Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/ Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Link: https://lore.kernel.org/r/20220818210215.8395-1-wsa+renesas@sang-engineering.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-09net: rename reference+tracking helpersJakub Kicinski
Netdev reference helpers have a dev_ prefix for historic reasons. Renaming the old helpers would be too much churn but we can rename the tracking ones which are relatively recent and should be the default for new code. Rename: dev_hold_track() -> netdev_hold() dev_put_track() -> netdev_put() dev_replace_track() -> netdev_ref_replace() Link: https://lore.kernel.org/r/20220608043955.919359-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-06netpoll: add net device refcount tracker to struct netpollEric Dumazet
Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-07-02Merge tag 'asm-generic-unaligned-5.14' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic Pull asm/unaligned.h unification from Arnd Bergmann: "Unify asm/unaligned.h around struct helper The get_unaligned()/put_unaligned() helpers are traditionally architecture specific, with the two main variants being the "access-ok.h" version that assumes unaligned pointer accesses always work on a particular architecture, and the "le-struct.h" version that casts the data to a byte aligned type before dereferencing, for architectures that cannot always do unaligned accesses in hardware. Based on the discussion linked below, it appears that the access-ok version is not realiable on any architecture, but the struct version probably has no downsides. This series changes the code to use the same implementation on all architectures, addressing the few exceptions separately" Link: https://lore.kernel.org/lkml/75d07691-1e4f-741f-9852-38c0b4f520bc@synopsys.com/ Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100363 Link: https://lore.kernel.org/lkml/20210507220813.365382-14-arnd@kernel.org/ Link: git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git unaligned-rework-v2 Link: https://lore.kernel.org/lkml/CAHk-=whGObOKruA_bU3aPGZfoDqZM1_9wBkwREp0H0FgR-90uQ@mail.gmail.com/ * tag 'asm-generic-unaligned-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: asm-generic: simplify asm/unaligned.h asm-generic: uaccess: 1-byte access is always aligned netpoll: avoid put_unaligned() on single character mwifiex: re-fix for unaligned accesses apparmor: use get_unaligned() only for multi-byte words partitions: msdos: fix one-byte get_unaligned() asm-generic: unaligned always use struct helpers asm-generic: unaligned: remove byteshift helpers powerpc: use linux/unaligned/le_struct.h on LE power7 m68k: select CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS sh: remove unaligned access for sh4a openrisc: always use unaligned-struct header asm-generic: use asm-generic/unaligned.h for most architectures
2021-06-01netpoll: don't require irqs disabled in rt kernelsWander Lairson Costa
write_msg(netconsole.c:836) calls netpoll_send_udp after a call to spin_lock_irqsave, which normally disables interrupts; but in PREEMPT_RT this call just locks an rt_mutex without disabling irqs. In this case, netpoll_send_udp is called with interrupts enabled. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-05-17netpoll: avoid put_unaligned() on single characterArnd Bergmann
With a planned cleanup, using put_unaligned() on a single character results in a harmless warning: In file included from ./arch/x86/include/generated/asm/unaligned.h:1, from include/linux/etherdevice.h:24, from net/core/netpoll.c:18: net/core/netpoll.c: In function 'netpoll_send_udp': include/asm-generic/unaligned.h:23:9: error: 'packed' attribute ignored for field of type 'unsigned char' [-Werror=attributes] net/core/netpoll.c:431:3: note: in expansion of macro 'put_unaligned' 431 | put_unaligned(0x60, (unsigned char *)ip6h); | ^~~~~~~~~~~~~ include/asm-generic/unaligned.h:23:9: error: 'packed' attribute ignored for field of type 'unsigned char' [-Werror=attributes] net/core/netpoll.c:459:3: note: in expansion of macro 'put_unaligned' 459 | put_unaligned(0x45, (unsigned char *)iph); | ^~~~~~~~~~~~~ Replace this with an open-coded pointer dereference. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2021-02-06Revert "net: Have netpoll bring-up DSA management interface"Vladimir Oltean
This reverts commit 1532b9778478577152201adbafa7738b1e844868. The above commit is good and it works, however it was meant as a bugfix for stable kernels and now we have more self-contained ways in DSA to handle the situation where the DSA master must be brought up. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-18net: Have netpoll bring-up DSA management interfaceFlorian Fainelli
DSA network devices rely on having their DSA management interface up and running otherwise their ndo_open() will return -ENETDOWN. Without doing this it would not be possible to use DSA devices as netconsole when configured on the command line. These devices also do not utilize the upper/lower linking so the check about the netpoll device having upper is not going to be a problem. The solution adopted here is identical to the one done for net/ipv4/ipconfig.c with 728c02089a0e ("net: ipv4: handle DSA enabled master network devices"), with the network namespace scope being restricted to that of the process configuring netpoll. Fixes: 04ff53f96a93 ("net: dsa: Add netconsole support") Tested-by: Vladimir Oltean <olteanv@gmail.com> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Link: https://lore.kernel.org/r/20201117035236.22658-1-f.fainelli@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-09-10net: make sure napi_list is safe for RCU traversalJakub Kicinski
netpoll needs to traverse dev->napi_list under RCU, make sure it uses the right iterator and that removal from this list is handled safely. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-26net: disable netpoll on fresh napisJakub Kicinski
napi_disable() makes sure to set the NAPI_STATE_NPSVC bit to prevent netpoll from accessing rings before init is complete. However, the same is not done for fresh napi instances in netif_napi_add(), even though we expect NAPI instances to be added as disabled. This causes crashes during driver reconfiguration (enabling XDP, changing the channel count) - if there is any printk() after netif_napi_add() but before napi_enable(). To ensure memory ordering is correct we need to use RCU accessors. Reported-by: Rob Sherwood <rsher@fb.com> Fixes: 2d8bff12699a ("netpoll: Close race condition between poll_one_napi and napi_disable") Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
generated by cgit v1.2.3 (git 2.39.1) at 2025-08-01 18:27:32 +0000