linux.git/drivers/net/ntb_netdev.c, branch v7.2 Linux kernel source tree NTB: ntb_netdev: Preserve RX queue depth on allocation failure 2026-08-11T09:04:55+00:00 Koichiro Den den@valinux.co.jp 2026-08-06T03:25:37+00:00 d2121faf133ac3bf9531b53a7e21273649a08517 ntb_netdev_rx_handler() hands the received skb to the network stack before allocating its replacement. If the allocation fails, nothing is reposted. Every failure therefore takes one buffer out of the RX queue while the interface remains up, and enough failures eventually stall reception. A retry path could refill the queue later, but ntb_netdev has none. Allocate the replacement first instead. If that fails, drop the packet and repost the same skb. This keeps the queue full and lets packet delivery resume as soon as memory is available again. Fixes: 548c237c0a99 ("net: Add support for NTB virtual ethernet device") Cc: stable@vger.kernel.org Signed-off-by: Koichiro Den <den@valinux.co.jp> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://patch.msgid.link/20260806032537.3526498-1-den@valinux.co.jp Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
ntb_netdev_rx_handler() hands the received skb to the network stack
before allocating its replacement. If the allocation fails, nothing is
reposted. Every failure therefore takes one buffer out of the RX queue
while the interface remains up, and enough failures eventually stall
reception.

A retry path could refill the queue later, but ntb_netdev has none.
Allocate the replacement first instead. If that fails, drop the packet
and repost the same skb. This keeps the queue full and lets packet
delivery resume as soon as memory is available again.

Fixes: 548c237c0a99 ("net: Add support for NTB virtual ethernet device")
Cc: stable@vger.kernel.org
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260806032537.3526498-1-den@valinux.co.jp
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
net: ntb_netdev: add SPDX tag and remove boilerplate license text 2026-03-20T00:17:32+00:00 Oskar Ray-Frayssinet rayfraytech@gmail.com 2026-03-18T21:11:53+00:00 b29580d58be6d4d24d66c89d9bea96db342cff00 Add SPDX-License-Identifier tag to reflect the dual GPL-2.0-only/BSD-3-Clause license, remove the redundant boilerplate license text and contact information, keeping only the driver description. Signed-off-by: Oskar Ray-Frayssinet <rayfraytech@gmail.com> Acked-by: Dave Jiang <dave.jiang@intel.com> Link: https://patch.msgid.link/20260318211153.9460-1-rayfraytech@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Add SPDX-License-Identifier tag to reflect the dual
GPL-2.0-only/BSD-3-Clause license, remove the redundant
boilerplate license text and contact information, keeping
only the driver description.

Signed-off-by: Oskar Ray-Frayssinet <rayfraytech@gmail.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260318211153.9460-1-rayfraytech@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: ntb_netdev: Support ethtool channels for multi-queue 2026-03-07T03:15:20+00:00 Koichiro Den den@valinux.co.jp 2026-03-05T15:56:39+00:00 24d9e73c7e000af7c1f1a1f669bdaa9bd7e88ea5 Support dynamic queue pair addition/removal via ethtool channels. Use the combined channel count to control the number of netdev TX/RX queues, each corresponding to a ntb_transport queue pair. When the number of queues is reduced, tear down and free the removed ntb_transport queue pairs (not just deactivate them) so other ntb_transport clients can reuse the freed resources. When the number of queues is increased, create additional queue pairs up to NTB_NETDEV_MAX_QUEUES (=64). The effective limit is determined by the underlying ntb_transport implementation and NTB hardware resources (the number of MWs), so set_channels may return -ENOSPC if no more QPs can be allocated. Keep the default at one queue pair to preserve the previous behavior. Signed-off-by: Koichiro Den <den@valinux.co.jp> Link: https://patch.msgid.link/20260305155639.1885517-5-den@valinux.co.jp Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Support dynamic queue pair addition/removal via ethtool channels.
Use the combined channel count to control the number of netdev TX/RX
queues, each corresponding to a ntb_transport queue pair.

When the number of queues is reduced, tear down and free the removed
ntb_transport queue pairs (not just deactivate them) so other
ntb_transport clients can reuse the freed resources.

When the number of queues is increased, create additional queue pairs up
to NTB_NETDEV_MAX_QUEUES (=64). The effective limit is determined by the
underlying ntb_transport implementation and NTB hardware resources (the
number of MWs), so set_channels may return -ENOSPC if no more QPs can be
allocated.

Keep the default at one queue pair to preserve the previous behavior.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
Link: https://patch.msgid.link/20260305155639.1885517-5-den@valinux.co.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: ntb_netdev: Factor out multi-queue helpers 2026-03-07T03:15:20+00:00 Koichiro Den den@valinux.co.jp 2026-03-05T15:56:38+00:00 b83bf617dc849f11e7b2f907540017b5aa42d167 Implementing .set_channels will otherwise duplicate the same multi-queue operations at multiple call sites. Factor out the following helpers: - ntb_netdev_update_carrier(): carrier is switched on when at least one QP link is up - ntb_netdev_queue_rx_drain(): drain and free all queued RX packets for one QP - ntb_netdev_queue_rx_fill(): prefill RX ring for one QP No functional change. Signed-off-by: Koichiro Den <den@valinux.co.jp> Link: https://patch.msgid.link/20260305155639.1885517-4-den@valinux.co.jp Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Implementing .set_channels will otherwise duplicate the same multi-queue
operations at multiple call sites. Factor out the following helpers:

  - ntb_netdev_update_carrier(): carrier is switched on when at least
                                 one QP link is up
  - ntb_netdev_queue_rx_drain(): drain and free all queued RX packets
                                 for one QP
  - ntb_netdev_queue_rx_fill():  prefill RX ring for one QP

No functional change.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
Link: https://patch.msgid.link/20260305155639.1885517-4-den@valinux.co.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: ntb_netdev: Gate subqueue stop/wake by transport link 2026-03-07T03:15:20+00:00 Koichiro Den den@valinux.co.jp 2026-03-05T15:56:37+00:00 304132b7a5e6de84737ed4735c124d3d515f8c7a When ntb_netdev is extended to multiple ntb_transport queue pairs, the netdev carrier can be up as long as at least one QP link is up. In that setup, a given QP may be link-down while the carrier remains on. Make the link event handler start/stop the corresponding netdev TX subqueue and drive carrier state based on whether any QP link is up. Also guard subqueue wake/start points in the TX completion and timer paths so a subqueue is not restarted while its QP link is down. Stop all queues in ndo_open() and let the link event handler wake each subqueue once ntb_transport link negotiation succeeds. Signed-off-by: Koichiro Den <den@valinux.co.jp> Link: https://patch.msgid.link/20260305155639.1885517-3-den@valinux.co.jp Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
When ntb_netdev is extended to multiple ntb_transport queue pairs, the
netdev carrier can be up as long as at least one QP link is up. In that
setup, a given QP may be link-down while the carrier remains on.

Make the link event handler start/stop the corresponding netdev TX
subqueue and drive carrier state based on whether any QP link is up.
Also guard subqueue wake/start points in the TX completion and timer
paths so a subqueue is not restarted while its QP link is down.

Stop all queues in ndo_open() and let the link event handler wake each
subqueue once ntb_transport link negotiation succeeds.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
Link: https://patch.msgid.link/20260305155639.1885517-3-den@valinux.co.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: ntb_netdev: Introduce per-queue context 2026-03-07T03:15:20+00:00 Koichiro Den den@valinux.co.jp 2026-03-05T15:56:36+00:00 ee970634c7773f248a0a27d8a645500371ae5249 Prepare ntb_netdev for multi-queue operation by moving queue-pair state out of struct ntb_netdev. Introduce struct ntb_netdev_queue to carry the ntb_transport_qp pointer, the per-QP TX timer and queue id. Pass this object as the callback context and convert the RX/TX handlers and link event path accordingly. The probe path allocates a fixed upper bound for netdev queues while instantiating only a single ntb_transport queue pair, preserving the previous behavior. Also store client_dev for future queue pair creation/removal via the ntb_transport API. Signed-off-by: Koichiro Den <den@valinux.co.jp> Link: https://patch.msgid.link/20260305155639.1885517-2-den@valinux.co.jp Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Prepare ntb_netdev for multi-queue operation by moving queue-pair state
out of struct ntb_netdev.

Introduce struct ntb_netdev_queue to carry the ntb_transport_qp pointer,
the per-QP TX timer and queue id. Pass this object as the callback
context and convert the RX/TX handlers and link event path accordingly.

The probe path allocates a fixed upper bound for netdev queues while
instantiating only a single ntb_transport queue pair, preserving the
previous behavior. Also store client_dev for future queue pair
creation/removal via the ntb_transport API.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
Link: https://patch.msgid.link/20260305155639.1885517-2-den@valinux.co.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
treewide, timers: Rename from_timer() to timer_container_of() 2025-06-08T07:07:37+00:00 Ingo Molnar mingo@kernel.org 2025-05-09T05:51:14+00:00 41cb08555c4164996d67c78b3bf1c658075b75f1 Move this API to the canonical timer_*() namespace. [ tglx: Redone against pre rc1 ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com 
Move this API to the canonical timer_*() namespace.

[ tglx: Redone against pre rc1 ]

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com
treewide: Switch/rename to timer_delete[_sync]() 2025-04-05T08:30:12+00:00 Thomas Gleixner tglx@linutronix.de 2025-04-05T08:17:26+00:00 8fa7292fee5c5240402371ea89ab285ec856c916 timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree over and remove the historical wrapper inlines. Conversion was done with coccinelle plus manual fixups where necessary. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> 
timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.

Conversion was done with coccinelle plus manual fixups where necessary.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
net: ntb_netdev: Move ntb_netdev_rx_handler() to call netif_rx() from __netif_rx() 2024-07-03T01:56:46+00:00 Dave Jiang dave.jiang@intel.com 2024-07-01T18:15:38+00:00 e15a5d821e5192a3769d846079bc9aa380139baf The following is emitted when using idxd (DSA) dmanegine as the data mover for ntb_transport that ntb_netdev uses. [74412.546922] BUG: using smp_processor_id() in preemptible [00000000] code: irq/52-idxd-por/14526 [74412.556784] caller is netif_rx_internal+0x42/0x130 [74412.562282] CPU: 6 PID: 14526 Comm: irq/52-idxd-por Not tainted 6.9.5 #5 [74412.569870] Hardware name: Intel Corporation ArcherCity/ArcherCity, BIOS EGSDCRB1.E9I.1752.P05.2402080856 02/08/2024 [74412.581699] Call Trace: [74412.584514] <TASK> [74412.586933] dump_stack_lvl+0x55/0x70 [74412.591129] check_preemption_disabled+0xc8/0xf0 [74412.596374] netif_rx_internal+0x42/0x130 [74412.600957] __netif_rx+0x20/0xd0 [74412.604743] ntb_netdev_rx_handler+0x66/0x150 [ntb_netdev] [74412.610985] ntb_complete_rxc+0xed/0x140 [ntb_transport] [74412.617010] ntb_rx_copy_callback+0x53/0x80 [ntb_transport] [74412.623332] idxd_dma_complete_txd+0xe3/0x160 [idxd] [74412.628963] idxd_wq_thread+0x1a6/0x2b0 [idxd] [74412.634046] irq_thread_fn+0x21/0x60 [74412.638134] ? irq_thread+0xa8/0x290 [74412.642218] irq_thread+0x1a0/0x290 [74412.646212] ? __pfx_irq_thread_fn+0x10/0x10 [74412.651071] ? __pfx_irq_thread_dtor+0x10/0x10 [74412.656117] ? __pfx_irq_thread+0x10/0x10 [74412.660686] kthread+0x100/0x130 [74412.664384] ? __pfx_kthread+0x10/0x10 [74412.668639] ret_from_fork+0x31/0x50 [74412.672716] ? __pfx_kthread+0x10/0x10 [74412.676978] ret_from_fork_asm+0x1a/0x30 [74412.681457] </TASK> The cause is due to the idxd driver interrupt completion handler uses threaded interrupt and the threaded handler is not hard or soft interrupt context. However __netif_rx() can only be called from interrupt context. Change the call to netif_rx() in order to allow completion via normal context for dmaengine drivers that utilize threaded irq handling. While the following commit changed from netif_rx() to __netif_rx(), baebdf48c360 ("net: dev: Makes sure netif_rx() can be invoked in any context."), the change should've been a noop instead. However, the code precedes this fix should've been using netif_rx_ni() or netif_rx_any_context(). Fixes: 548c237c0a99 ("net: Add support for NTB virtual ethernet device") Reported-by: Jerry Dai <jerry.dai@intel.com> Tested-by: Jerry Dai <jerry.dai@intel.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Link: https://patch.msgid.link/20240701181538.3799546-1-dave.jiang@intel.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
The following is emitted when using idxd (DSA) dmanegine as the data
mover for ntb_transport that ntb_netdev uses.

[74412.546922] BUG: using smp_processor_id() in preemptible [00000000] code: irq/52-idxd-por/14526
[74412.556784] caller is netif_rx_internal+0x42/0x130
[74412.562282] CPU: 6 PID: 14526 Comm: irq/52-idxd-por Not tainted 6.9.5 #5
[74412.569870] Hardware name: Intel Corporation ArcherCity/ArcherCity, BIOS EGSDCRB1.E9I.1752.P05.2402080856 02/08/2024
[74412.581699] Call Trace:
[74412.584514]  <TASK>
[74412.586933]  dump_stack_lvl+0x55/0x70
[74412.591129]  check_preemption_disabled+0xc8/0xf0
[74412.596374]  netif_rx_internal+0x42/0x130
[74412.600957]  __netif_rx+0x20/0xd0
[74412.604743]  ntb_netdev_rx_handler+0x66/0x150 [ntb_netdev]
[74412.610985]  ntb_complete_rxc+0xed/0x140 [ntb_transport]
[74412.617010]  ntb_rx_copy_callback+0x53/0x80 [ntb_transport]
[74412.623332]  idxd_dma_complete_txd+0xe3/0x160 [idxd]
[74412.628963]  idxd_wq_thread+0x1a6/0x2b0 [idxd]
[74412.634046]  irq_thread_fn+0x21/0x60
[74412.638134]  ? irq_thread+0xa8/0x290
[74412.642218]  irq_thread+0x1a0/0x290
[74412.646212]  ? __pfx_irq_thread_fn+0x10/0x10
[74412.651071]  ? __pfx_irq_thread_dtor+0x10/0x10
[74412.656117]  ? __pfx_irq_thread+0x10/0x10
[74412.660686]  kthread+0x100/0x130
[74412.664384]  ? __pfx_kthread+0x10/0x10
[74412.668639]  ret_from_fork+0x31/0x50
[74412.672716]  ? __pfx_kthread+0x10/0x10
[74412.676978]  ret_from_fork_asm+0x1a/0x30
[74412.681457]  </TASK>

The cause is due to the idxd driver interrupt completion handler uses
threaded interrupt and the threaded handler is not hard or soft interrupt
context. However __netif_rx() can only be called from interrupt context.
Change the call to netif_rx() in order to allow completion via normal
context for dmaengine drivers that utilize threaded irq handling.

While the following commit changed from netif_rx() to __netif_rx(),
baebdf48c360 ("net: dev: Makes sure netif_rx() can be invoked in any context."),
the change should've been a noop instead. However, the code precedes this
fix should've been using netif_rx_ni() or netif_rx_any_context().

Fixes: 548c237c0a99 ("net: Add support for NTB virtual ethernet device")
Reported-by: Jerry Dai <jerry.dai@intel.com>
Tested-by: Jerry Dai <jerry.dai@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20240701181538.3799546-1-dave.jiang@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: annotate writes on dev->mtu from ndo_change_mtu() 2024-05-07T23:19:14+00:00 Eric Dumazet edumazet@google.com 2024-05-06T10:28:12+00:00 1eb2cded45b35816085c1f962933c187d970f9dc Simon reported that ndo_change_mtu() methods were never updated to use WRITE_ONCE(dev->mtu, new_mtu) as hinted in commit 501a90c94510 ("inet: protect against too small mtu values.") We read dev->mtu without holding RTNL in many places, with READ_ONCE() annotations. It is time to take care of ndo_change_mtu() methods to use corresponding WRITE_ONCE() Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Simon Horman <horms@kernel.org> Closes: https://lore.kernel.org/netdev/20240505144608.GB67882@kernel.org/ Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Simon Horman <horms@kernel.org> Acked-by: Shannon Nelson <shannon.nelson@amd.com> Link: https://lore.kernel.org/r/20240506102812.3025432-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Simon reported that ndo_change_mtu() methods were never
updated to use WRITE_ONCE(dev->mtu, new_mtu) as hinted
in commit 501a90c94510 ("inet: protect against too small
mtu values.")

We read dev->mtu without holding RTNL in many places,
with READ_ONCE() annotations.

It is time to take care of ndo_change_mtu() methods
to use corresponding WRITE_ONCE()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Simon Horman <horms@kernel.org>
Closes: https://lore.kernel.org/netdev/20240505144608.GB67882@kernel.org/
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Shannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20240506102812.3025432-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>