* Re: [PATCH 0/6] SUNRPC: Address remaining cache_check_rcu() UAF in cache content files
From: yangerkun @ 2026-05-08 3:08 UTC (permalink / raw)
To: Chuck Lever, Misbah Anjum N, Jeff Layton, NeilBrown,
Olga Kornievskaia, Dai Ngo, Tom Talpey, Trond Myklebust,
Anna Schumaker, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, yi.zhang
Cc: linux-nfs, linux-kernel, netdev, Chuck Lever
In-Reply-To: <4bb9ed6b-1a64-406a-9239-b0560ca963cc@huawei.com>
在 2026/5/8 10:45, yangerkun 写道:
> Hello Chuck,
>
> 在 2026/5/8 0:12, Chuck Lever 写道:
>> Hello Erkun -
>>
>> On Thu, May 7, 2026, at 11:09 AM, yangerkun wrote:
>>> Hi,
>>>
>>> 在 2026/5/1 22:51, Chuck Lever 写道:
>>>> Misbah Anjum reported a use-after-free in cache_check_rcu()
>>>> reached through e_show() while sosreport was reading
>>>> /proc/fs/nfsd/exports on ppc64le. Two fixes for that report
>>>> landed in v7.0:
>>>>
>>>> 48db892356d6 ("NFSD: Defer sub-object cleanup in export put
>>>> callbacks")
>>>> e7fcf179b82d ("NFSD: Hold net reference for the lifetime of /
>>>> proc/fs/nfs/exports fd")
>>>
>>> Back to the problem fixed by this patches, I'm a little confused why
>>> this UAF can be trigged.
>>>
>>> Before this patches, svc_export_put show as follow:
>>>
>>> 368 static void svc_export_put(struct kref *ref)
>>> 369 {
>>> 370 struct svc_export *exp = container_of(ref, struct
>>> svc_export, h.ref);
>>> 371
>>> 372 path_put(&exp->ex_path);
>>> 373 auth_domain_put(exp->ex_client);
>>> 374 call_rcu(&exp->ex_rcu, svc_export_release);
>>> 375 }
>>>
>>> The auth_domain_put function releases ->name using call_rcu, and
>>> path_put may release the dentry also via call_rcu. All of this seems to
>>> prevent e_show from causing a UAF. Could you point out which line in
>>> d_path triggers the issue?
>>
>> The dentry, the mount, and the auth_domain ->name buffer all
>> end up RCU-freed (dentry_free() and delayed_free_vfsmnt in
>> fs/, svcauth_unix_domain_release_rcu() in svcauth_unix.c).
>> The eventual kfree isn't the problem.
>>
>> The problem is the synchronous teardown inside path_put(),
>> which runs before svc_export_put() ever reaches its own
>> call_rcu():
>>
>> path_put(&exp->ex_path)
>> -> dput(dentry)
>> -> __dentry_kill() [if last ref]
>> -> __d_drop() /* unhashes */
>> -> dentry_unlink_inode() /* d_inode = NULL */
>> -> d_op->d_release() if set
>> -> drops parent d_lockref /* may cascade up */
>> -> dentry_free() /* call_rcu deferred */
>> -> mntput(mnt) /* deferred via task_work */
>>
>> The dentry pointer itself is RCU-safe, so prepend_path()'s walk
>> of d_parent and d_name doesn't read freed memory. But by the
>> time the reader gets there, __d_clear_type_and_inode() has
>> already stored NULL into d_inode, __d_drop() has broken the
>> hash linkage, and the parent's d_lockref has been decremented
>> -- which can in turn fire __dentry_kill() on the parent, and
>> on up the tree. An e_show() that's still inside its cache RCU
>> read section walks into that half-dismantled state through
>> seq_path(), and that's the NULL deref Misbah reported.
>
> Thank you for your detailed explanation! Yes, e_show might be called
> when the state is partially dismantled, but after carefully reviewing
> the code with dput up to __dentry_kill, I still cannot find anything
> that could cause this issue. Additionally, the comments for prepend_path
> indicate that they have already taken into account that the dentry can
> be removed concurrently. I have also run some tests on my arm64 QEMU,
> but I couldn't reproduce the problem either. Could you please help me
> identify the specific line or pointer in the dentry that triggers this
> use-after-free or null pointer issue?
>
> Maybe I am not be very familiar with the code, which caused me to fail
> to identify the real root cause. I'm so sorry for that.
>
>
> 265 char *d_path(const struct path *path, char *buf, int buflen)
> 266 {
> 267 DECLARE_BUFFER(b, buf, buflen);
> 268 struct path root;
> 269
> 270 /*
> 271 * We have various synthetic filesystems that never get
> mounted. On
> 272 * these filesystems dentries are never used for lookup
> purposes, and
> 273 * thus don't need to be hashed. They also don't need a
> name until a
> 274 * user wants to identify the object in /proc/pid/fd/. The
> little hack
> 275 * below allows us to generate a name for these objects on
> demand:
> 276 *
> 277 * Some pseudo inodes are mountable. When they are mounted
> 278 * path->dentry == path->mnt->mnt_root. In that case don't
> call d_dname
> 279 * and instead have d_path return the mounted path.
> 280 */
> 281 if (path->dentry->d_op && path->dentry->d_op->d_dname &&
> 282 (!IS_ROOT(path->dentry) || path->dentry != path->mnt-
> >mnt_root))
> 283 return path->dentry->d_op->d_dname(path->dentry,
> buf, buflen);
> 284
> 285 rcu_read_lock();
> 286 get_fs_root_rcu(current->fs, &root);
> 287 if (unlikely(d_unlinked(path->dentry)))
> 288 prepend(&b, " (deleted)", 11);
> 289 else
> 290 prepend_char(&b, 0);
> 291 prepend_path(path, &root, &b);
> 292 rcu_read_unlock();
> 293
> 294 return extract_string(&b);
> 295 }
>
>
>>
>> The earlier fix (2530766492ec, "nfsd: fix UAF when access
>> ex_uuid or ex_stats") moved the kfree of ex_uuid and ex_stats
>> into svc_export_release() so those are RCU-safe now.
>> path_put() and auth_domain_put() couldn't go in there because
>> both may sleep, and call_rcu callbacks run in softirq context.
>> This series uses queue_rcu_work() instead: it defers past the
>> grace period AND runs the callback in process context, so the
>> sleeping puts move into the deferred path and the window
>> closes.
>
> Yeah, I can get this! Thanks again for your detail explanation!
Also, could the scenario described in this commit be triggered again?
commit 69d803c40edeaf94089fbc8751c9b746cdc35044
Author: Yang Erkun <yangerkun@huawei.com>
Date: Mon Dec 16 22:21:52 2024 +0800
nfsd: Revert "nfsd: release svc_expkey/svc_export with rcu_work"
This reverts commit f8c989a0c89a75d30f899a7cabdc14d72522bb8d.
Before this commit, svc_export_put or expkey_put will call path_put
with
sync mode. After this commit, path_put will be called with async mode.
And this can lead the unexpected results show as follow.
mkfs.xfs -f /dev/sda
echo "/ *(rw,no_root_squash,fsid=0)" > /etc/exports
echo "/mnt *(rw,no_root_squash,fsid=1)" >> /etc/exports
exportfs -ra
service nfs-server start
mount -t nfs -o vers=4.0 127.0.0.1:/mnt /mnt1
mount /dev/sda /mnt/sda
touch /mnt1/sda/file
exportfs -r
umount /mnt/sda # failed unexcepted
The touch will finally call nfsd_cross_mnt, add refcount to mount, and
then add cache_head. Before this commit, exportfs -r will call
cache_flush to cleanup all cache_head, and path_put in
svc_export_put/expkey_put will be finished with sync mode. So, the
latter umount will always success. However, after this commit, path_put
will be called with async mode, the latter umount may failed, and if
we add some delay, umount will success too. Personally I think this bug
and should be fixed. We first revert before bugfix patch, and then fix
the original bug with a different way.
Fixes: f8c989a0c89a ("nfsd: release svc_expkey/svc_export with
rcu_work")
Signed-off-by: Yang Erkun <yangerkun@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
>
> Thanks,
> Erkun.
>
>>
>>
>
^ permalink raw reply
* RE: [RFC 1/4] net: fec: do not use readl()/writel() for ColdFire
From: Wei Fang @ 2026-05-08 2:46 UTC (permalink / raw)
To: Greg Ungerer, linux-m68k@lists.linux-m68k.org
Cc: linux-kernel@vger.kernel.org, arnd@kernel.org, Greg Ungerer,
Frank Li, Shenwei Wang, netdev@vger.kernel.org
In-Reply-To: <20260506142644.3234270-2-gerg@kernel.org>
> static void
> fec_stop(struct net_device *ndev)
> {
> struct fec_enet_private *fep = netdev_priv(ndev);
> - u32 rmii_mode = readl(fep->hwp + FEC_R_CNTRL) & FEC_RCR_RMII;
> + u32 rmii_mode = fec_readl(fep->hwp + FEC_R_CNTRL) & FEC_RCR_RMII;
This is not an issue, but since you changed this line, the new code should
follow the "reverse xmas tree" style.
See: https://elixir.bootlin.com/linux/v7.0.1/source/Documentation/process/maintainer-netdev.rst#L380
> u32 val;
>
> /* We cannot expect a graceful transmit stop without link !!! */
> if (fep->link) {
> - writel(1, fep->hwp + FEC_X_CNTRL); /* Graceful transmit stop */
> + fec_writel(1, fep->hwp + FEC_X_CNTRL); /* Graceful transmit stop */
> udelay(10);
> - if (!(readl(fep->hwp + FEC_IEVENT) & FEC_ENET_GRA))
> + if (!(fec_readl(fep->hwp + FEC_IEVENT) & FEC_ENET_GRA))
> netdev_err(ndev, "Graceful transmit stop did not complete!\n");
> }
>
^ permalink raw reply
* Re: [PATCH 0/6] SUNRPC: Address remaining cache_check_rcu() UAF in cache content files
From: yangerkun @ 2026-05-08 2:45 UTC (permalink / raw)
To: Chuck Lever, Misbah Anjum N, Jeff Layton, NeilBrown,
Olga Kornievskaia, Dai Ngo, Tom Talpey, Trond Myklebust,
Anna Schumaker, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, yi.zhang
Cc: linux-nfs, linux-kernel, netdev, Chuck Lever
In-Reply-To: <76a10e49-54a6-4813-8b58-b7cd0820fdc6@app.fastmail.com>
Hello Chuck,
在 2026/5/8 0:12, Chuck Lever 写道:
> Hello Erkun -
>
> On Thu, May 7, 2026, at 11:09 AM, yangerkun wrote:
>> Hi,
>>
>> 在 2026/5/1 22:51, Chuck Lever 写道:
>>> Misbah Anjum reported a use-after-free in cache_check_rcu()
>>> reached through e_show() while sosreport was reading
>>> /proc/fs/nfsd/exports on ppc64le. Two fixes for that report
>>> landed in v7.0:
>>>
>>> 48db892356d6 ("NFSD: Defer sub-object cleanup in export put callbacks")
>>> e7fcf179b82d ("NFSD: Hold net reference for the lifetime of /proc/fs/nfs/exports fd")
>>
>> Back to the problem fixed by this patches, I'm a little confused why
>> this UAF can be trigged.
>>
>> Before this patches, svc_export_put show as follow:
>>
>> 368 static void svc_export_put(struct kref *ref)
>> 369 {
>> 370 struct svc_export *exp = container_of(ref, struct
>> svc_export, h.ref);
>> 371
>> 372 path_put(&exp->ex_path);
>> 373 auth_domain_put(exp->ex_client);
>> 374 call_rcu(&exp->ex_rcu, svc_export_release);
>> 375 }
>>
>> The auth_domain_put function releases ->name using call_rcu, and
>> path_put may release the dentry also via call_rcu. All of this seems to
>> prevent e_show from causing a UAF. Could you point out which line in
>> d_path triggers the issue?
>
> The dentry, the mount, and the auth_domain ->name buffer all
> end up RCU-freed (dentry_free() and delayed_free_vfsmnt in
> fs/, svcauth_unix_domain_release_rcu() in svcauth_unix.c).
> The eventual kfree isn't the problem.
>
> The problem is the synchronous teardown inside path_put(),
> which runs before svc_export_put() ever reaches its own
> call_rcu():
>
> path_put(&exp->ex_path)
> -> dput(dentry)
> -> __dentry_kill() [if last ref]
> -> __d_drop() /* unhashes */
> -> dentry_unlink_inode() /* d_inode = NULL */
> -> d_op->d_release() if set
> -> drops parent d_lockref /* may cascade up */
> -> dentry_free() /* call_rcu deferred */
> -> mntput(mnt) /* deferred via task_work */
>
> The dentry pointer itself is RCU-safe, so prepend_path()'s walk
> of d_parent and d_name doesn't read freed memory. But by the
> time the reader gets there, __d_clear_type_and_inode() has
> already stored NULL into d_inode, __d_drop() has broken the
> hash linkage, and the parent's d_lockref has been decremented
> -- which can in turn fire __dentry_kill() on the parent, and
> on up the tree. An e_show() that's still inside its cache RCU
> read section walks into that half-dismantled state through
> seq_path(), and that's the NULL deref Misbah reported.
Thank you for your detailed explanation! Yes, e_show might be called
when the state is partially dismantled, but after carefully reviewing
the code with dput up to __dentry_kill, I still cannot find anything
that could cause this issue. Additionally, the comments for prepend_path
indicate that they have already taken into account that the dentry can
be removed concurrently. I have also run some tests on my arm64 QEMU,
but I couldn't reproduce the problem either. Could you please help me
identify the specific line or pointer in the dentry that triggers this
use-after-free or null pointer issue?
Maybe I am not be very familiar with the code, which caused me to fail
to identify the real root cause. I'm so sorry for that.
265 char *d_path(const struct path *path, char *buf, int buflen)
266 {
267 DECLARE_BUFFER(b, buf, buflen);
268 struct path root;
269
270 /*
271 * We have various synthetic filesystems that never get
mounted. On
272 * these filesystems dentries are never used for lookup
purposes, and
273 * thus don't need to be hashed. They also don't need a
name until a
274 * user wants to identify the object in /proc/pid/fd/. The
little hack
275 * below allows us to generate a name for these objects on
demand:
276 *
277 * Some pseudo inodes are mountable. When they are mounted
278 * path->dentry == path->mnt->mnt_root. In that case don't
call d_dname
279 * and instead have d_path return the mounted path.
280 */
281 if (path->dentry->d_op && path->dentry->d_op->d_dname &&
282 (!IS_ROOT(path->dentry) || path->dentry !=
path->mnt->mnt_root))
283 return path->dentry->d_op->d_dname(path->dentry,
buf, buflen);
284
285 rcu_read_lock();
286 get_fs_root_rcu(current->fs, &root);
287 if (unlikely(d_unlinked(path->dentry)))
288 prepend(&b, " (deleted)", 11);
289 else
290 prepend_char(&b, 0);
291 prepend_path(path, &root, &b);
292 rcu_read_unlock();
293
294 return extract_string(&b);
295 }
>
> The earlier fix (2530766492ec, "nfsd: fix UAF when access
> ex_uuid or ex_stats") moved the kfree of ex_uuid and ex_stats
> into svc_export_release() so those are RCU-safe now.
> path_put() and auth_domain_put() couldn't go in there because
> both may sleep, and call_rcu callbacks run in softirq context.
> This series uses queue_rcu_work() instead: it defers past the
> grace period AND runs the callback in process context, so the
> sleeping puts move into the deferred path and the window
> closes.
Yeah, I can get this! Thanks again for your detail explanation!
Thanks,
Erkun.
>
>
^ permalink raw reply
* Re: [PATCH net v2] ice: fix packet corruption due to extraneous page flip
From: John Ousterhout @ 2026-05-08 2:37 UTC (permalink / raw)
To: Jacob Keller
Cc: anthony.l.nguyen, Jakub Kicinski, Paolo Abeni, intel-wired-lan,
przemyslaw.kitszel, netdev, stable
In-Reply-To: <379cd3dc-aff5-4fcd-bf9f-4878ae21ee74@intel.com>
Correct: this patch only applies to the ice driver before its conversion.
The patch applies to versions 6.18.27 and 6.12.86. I believe the bug
may also be present in 6.6.137, but the code has a slightly different
structure there (the function ice_put_rx_mbuf doesn't yet exist in
that version) so the patch would need to be reworked a bit.
This situation isn't all that rare. It isn't a zero-length packet that
triggers it; it seems to happen if a packet uses every available byte
in a buffer, ending precisely at the end of the buffer. When this
happens, the NIC seems to generate an extra zero-length "buffer". This
happens quite frequently (thousands of times per second in some of my
workloads).
What keeps corruption from happening constantly is that there is only
a problem if the "other half" of the buffer page is still active when
the 0-length buffer is received from the NIC. I suspect that with TCP
this is pretty unlikely: packet buffers get recycled quickly. If the
other half is not in use, then it doesn't matter whether the page gets
"flipped" while processing the 0-length buffer. I ran into this
problem because I was testing Homa under conditions that caused some
packet buffers to stay alive for longer periods of time.
-John-
On Thu, May 7, 2026 at 3:11 PM Jacob Keller <jacob.e.keller@intel.com> wrote:
>
> On 5/7/2026 11:38 AM, John Ousterhout wrote:
> > Note: major revisions to the ice driver make this patch irrelevant
> > for recent versions. It applies to longterm stable versions
> > 6.18.27 and 6.12.86; it also seems relevant for 6.6.137, but would
> > need modifications for that version. I have not examined earlier
> > versions
> >
>
> From this description I take it this only applies to the ice driver
> prior to its conversion to page pool?
>
> In that case, I think you need to Cc: stable@vger.kernel.org and include
> the relevant versions you intend to target.
>
> I think this case is "unique" since there would not be an upstream
> equivalent patch. But that is merely because we removed the faulty code
> before it could be fixed.
>
> I'm not 100% sure whta method to follow since typical stable rules don't
> really like taking patches that don't apply to mainline...
>
> Even with it being somewhat rare to get 0 size packet, it is not
> impossible and packet corruption is a Big(TM) deal.
>
> Thanks,
> Jake
>
> > Signed-off-by: John Ousterhout <ouster@cs.stanford.edu>
> > ---
> > drivers/net/ethernet/intel/ice/ice_txrx.c | 23 ++++++++++++++++++++---
> > 1 file changed, 20 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
> > index 51c459a3e722..081c7a7392b7 100644
> > --- a/drivers/net/ethernet/intel/ice/ice_txrx.c
> > +++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
> > @@ -1215,6 +1215,13 @@ static void ice_put_rx_mbuf(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
> > xdp_frags = xdp_get_shared_info_from_buff(xdp)->nr_frags;
> >
> > while (idx != ntc) {
> > + union ice_32b_rx_flex_desc *rx_desc;
> > + unsigned int size;
> > +
> > + rx_desc = ICE_RX_DESC(rx_ring, idx);
> > + size = le16_to_cpu(rx_desc->wb.pkt_len) &
> > + ICE_RX_FLX_DESC_PKT_LEN_M;
> > +
> > buf = &rx_ring->rx_buf[idx];
> > if (++idx == cnt)
> > idx = 0;
> > @@ -1224,10 +1231,20 @@ static void ice_put_rx_mbuf(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
> > * To do this, only adjust pagecnt_bias for fragments up to
> > * the total remaining after the XDP program has run.
> > */
> > - if (verdict != ICE_XDP_CONSUMED)
> > - ice_rx_buf_adjust_pg_offset(buf, xdp->frame_sz);
> > - else if (i++ <= xdp_frags)
> > + if (verdict != ICE_XDP_CONSUMED) {
> > + /* Don't "flip" the page if size is 0: in this case
> > + * the data in the current half will not be used so
> > + * it's OK to reuse that half. And, since the bias
> > + * didn't get decremented for this half, the page can
> > + * be returned to the NIC even if the other half is
> > + * still in use, so flipping the page could cause
> > + * live packet data to be overwritten.
> > + */
> > + if (size != 0)
> > + ice_rx_buf_adjust_pg_offset(buf, xdp->frame_sz);
> > + } else if (i++ <= xdp_frags) {
> > buf->pagecnt_bias++;
> > + }
> >
> > ice_put_rx_buf(rx_ring, buf);
> > }
>
^ permalink raw reply
* [PATCH net-next v3 8/8] selftests: drv-net: add netkit devmem tests
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
In-Reply-To: <20260507-tcp-dm-netkit-v3-0-52821445867c@meta.com>
From: Bobby Eshleman <bobbyeshleman@meta.com>
Add nk_devmem.py with four tests for TCP devmem through a netkit device:
These tests are just duplicates of the original devmem tests, with some
adjusted parameters such as telling ncdevmem to avoid device setup
(since it only has access to netkit, not a phys device).
Each test uses NetDrvContEnv with primary_rx_redirect=True to set up the
BPF redirect program on the primary netkit interface.
The NIC (HDS, RSS, queue lease) is configured once in main() before
ksft_run() and torn down in a finally block via cleanup_nic(), mirroring
the nk_qlease.py pattern. This avoids re-toggling NIC settings around
every test case.
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v4:
- Call configure_nic()/cleanup_nic() once around ksft_run() rather than
relying on per-test configuration inside the run_* helpers.
Changes in v3:
- Reorder os.path expressions
- Drop @ksft_disruptive from check_nk_rx_hds to mirror the original
check_rx_hds in devmem.py
Changes in v2:
- Add nk_devmem.py to TEST_PROGS in Makefile (Sashiko)
---
tools/testing/selftests/drivers/net/hw/Makefile | 1 +
.../testing/selftests/drivers/net/hw/nk_devmem.py | 55 ++++++++++++++++++++++
2 files changed, 56 insertions(+)
diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index 85ca4d1ecf9e..2f78c6aec397 100644
--- a/tools/testing/selftests/drivers/net/hw/Makefile
+++ b/tools/testing/selftests/drivers/net/hw/Makefile
@@ -34,6 +34,7 @@ TEST_PROGS = \
irq.py \
loopback.sh \
nic_timestamp.py \
+ nk_devmem.py \
nk_netns.py \
nk_qlease.py \
ntuple.py \
diff --git a/tools/testing/selftests/drivers/net/hw/nk_devmem.py b/tools/testing/selftests/drivers/net/hw/nk_devmem.py
new file mode 100755
index 000000000000..0e36a0fa9688
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/nk_devmem.py
@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""Test devmem TCP with netkit."""
+
+import os
+from lib.py import ksft_run, ksft_exit, ksft_disruptive
+from lib.py import NetDrvContEnv
+from lib.py.devmem import (setup_test, require_devmem, configure_nic,
+ cleanup_nic, run_rx, run_tx, run_tx_chunks,
+ run_rx_hds)
+
+
+@ksft_disruptive
+def check_nk_rx(cfg) -> None:
+ """Run the devmem RX test through netkit."""
+ run_rx(cfg)
+
+
+@ksft_disruptive
+def check_nk_tx(cfg) -> None:
+ """Run the devmem TX test through netkit."""
+ run_tx(cfg)
+
+
+@ksft_disruptive
+def check_nk_tx_chunks(cfg) -> None:
+ """Run the devmem TX chunking test through netkit."""
+ run_tx_chunks(cfg)
+
+
+def check_nk_rx_hds(cfg) -> None:
+ """Run the HDS test through netkit."""
+ run_rx_hds(cfg)
+
+
+def main() -> None:
+ """Configure the NIC once, then run the netkit devmem test cases."""
+ with NetDrvContEnv(__file__, rxqueues=2, primary_rx_redirect=True) as cfg:
+ setup_test(cfg,
+ os.path.join(os.path.dirname(os.path.abspath(__file__)),
+ "ncdevmem"))
+
+ require_devmem(cfg)
+ configure_nic(cfg)
+ try:
+ ksft_run([check_nk_rx, check_nk_tx, check_nk_tx_chunks,
+ check_nk_rx_hds], args=(cfg,))
+ finally:
+ cleanup_nic(cfg)
+
+ ksft_exit()
+
+
+if __name__ == "__main__":
+ main()
--
2.53.0-Meta
^ permalink raw reply related
* [PATCH net-next v3 7/8] selftests: drv-net: add primary_rx_redirect support to NetDrvContEnv
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
In-Reply-To: <20260507-tcp-dm-netkit-v3-0-52821445867c@meta.com>
From: Bobby Eshleman <bobbyeshleman@meta.com>
When sending from a namespace that has access to a netkit device with a
leased queue, the nk primary in the host namespace needs to redirect its
RX to the physical device. This patch adds that redirection bpf program
and teaches the harness to install it.
Add primary_rx_redirect=False parameter to NetDrvContEnv.__init__().
When enabled, _attach_primary_rx_redirect_bpf() attaches a new BPF TC
program (nk_primary_rx_redirect.bpf.c) to the primary (host-side) netkit
interface. The program redirects non-ICMPv6 IPv6 packets to the physical
NIC via bpf_redirect_neigh(), with the physical ifindex configured via
the .bss map. ICMPv6 is left on the host's netkit primary so IPv6
neighbor discovery still work locally.
Extract _find_bss_map_id() from _attach_bpf() into a reusable helper so
other BPF attachment methods can use it.
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v3:
- nk_primary_rx_redirect.bpf.c: add header includes to avoid hardcoding
values
- update commit message explaining why ICMP is passed through
- env.py: re-use _tc_ensure_clsact() (had to add ifname paramater)
- env.py: gate the remote IPv6 host route install on primary_rx_redirect
by moving it from _setup_ns() into _attach_primary_rx_redirect_bpf()
---
.../drivers/net/hw/nk_primary_rx_redirect.bpf.c | 39 +++++++++
tools/testing/selftests/drivers/net/lib/py/env.py | 93 +++++++++++++++++-----
2 files changed, 114 insertions(+), 18 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/hw/nk_primary_rx_redirect.bpf.c b/tools/testing/selftests/drivers/net/hw/nk_primary_rx_redirect.bpf.c
new file mode 100644
index 000000000000..46ff494b23de
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/nk_primary_rx_redirect.bpf.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <linux/pkt_cls.h>
+#include <linux/if_ether.h>
+#include <linux/in.h>
+#include <linux/ipv6.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+#define ctx_ptr(field) ((void *)(long)(field))
+
+volatile __u32 phys_ifindex;
+
+SEC("tc/ingress")
+int nk_primary_rx_redirect(struct __sk_buff *skb)
+{
+ void *data_end = ctx_ptr(skb->data_end);
+ void *data = ctx_ptr(skb->data);
+ struct ethhdr *eth;
+ struct ipv6hdr *ip6h;
+
+ eth = data;
+ if ((void *)(eth + 1) > data_end)
+ return TC_ACT_OK;
+
+ if (eth->h_proto != bpf_htons(ETH_P_IPV6))
+ return TC_ACT_OK;
+
+ ip6h = data + sizeof(struct ethhdr);
+ if ((void *)(ip6h + 1) > data_end)
+ return TC_ACT_OK;
+
+ if (ip6h->nexthdr == IPPROTO_ICMPV6)
+ return TC_ACT_OK;
+
+ return bpf_redirect_neigh(phys_ifindex, NULL, 0, 0);
+}
+
+char __license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/drivers/net/lib/py/env.py b/tools/testing/selftests/drivers/net/lib/py/env.py
index 409b41922245..af8e1de8ed7b 100644
--- a/tools/testing/selftests/drivers/net/lib/py/env.py
+++ b/tools/testing/selftests/drivers/net/lib/py/env.py
@@ -336,15 +336,18 @@ class NetDrvContEnv(NetDrvEpEnv):
+---------------+
"""
- def __init__(self, src_path, rxqueues=1, **kwargs):
+ def __init__(self, src_path, rxqueues=1, primary_rx_redirect=False, **kwargs):
self.netns = None
self._nk_host_ifname = None
self.nk_guest_ifname = None
self._tc_clsact_added = False
self._tc_attached = False
+ self._primary_rx_redirect_attached = False
+ self._primary_rx_redirect_clsact_added = False
self._bpf_prog_pref = None
self._bpf_prog_id = None
self._init_ns_attached = False
+ self._remote_route_added = False
self._old_fwd = None
self._old_accept_ra = None
@@ -396,8 +399,18 @@ class NetDrvContEnv(NetDrvEpEnv):
self._setup_ns()
self._attach_bpf()
+ if primary_rx_redirect:
+ self._attach_primary_rx_redirect_bpf()
def __del__(self):
+ if self._primary_rx_redirect_attached:
+ cmd(f"tc filter del dev {self._nk_host_ifname} ingress", fail=False)
+ self._primary_rx_redirect_attached = False
+
+ if self._primary_rx_redirect_clsact_added:
+ cmd(f"tc qdisc del dev {self._nk_host_ifname} clsact", fail=False)
+ self._primary_rx_redirect_clsact_added = False
+
if self._tc_attached:
cmd(f"tc filter del dev {self.ifname} ingress pref {self._bpf_prog_pref}")
self._tc_attached = False
@@ -406,6 +419,11 @@ class NetDrvContEnv(NetDrvEpEnv):
cmd(f"tc qdisc del dev {self.ifname} clsact")
self._tc_clsact_added = False
+ if self._remote_route_added:
+ cmd(f"ip -6 route del {self.nk_guest_ipv6}/128",
+ host=self.remote, fail=False)
+ self._remote_route_added = False
+
if self._nk_host_ifname:
cmd(f"ip link del dev {self._nk_host_ifname}")
self._nk_host_ifname = None
@@ -459,13 +477,19 @@ class NetDrvContEnv(NetDrvEpEnv):
ip(f"-6 addr add {self.nk_guest_ipv6}/64 dev {self.nk_guest_ifname} nodad", ns=self.netns)
ip(f"-6 route add default via fe80::1 dev {self.nk_guest_ifname}", ns=self.netns)
- def _tc_ensure_clsact(self):
- qdisc = json.loads(cmd(f"tc -j qdisc show dev {self.ifname}").stdout)
+ def _tc_ensure_clsact(self, ifname=None):
+ """Ensure a clsact qdisc exists on @ifname.
+
+ Returns True if this call added the qdisc, otherwise returns False.
+ """
+ if ifname is None:
+ ifname = self.ifname
+ qdisc = json.loads(cmd(f"tc -j qdisc show dev {ifname}").stdout)
for q in qdisc:
if q['kind'] == 'clsact':
- return
- cmd(f"tc qdisc add dev {self.ifname} clsact")
- self._tc_clsact_added = True
+ return False
+ cmd(f"tc qdisc add dev {ifname} clsact")
+ return True
def _get_bpf_prog_ids(self):
filters = json.loads(cmd(f"tc -j filter show dev {self.ifname} ingress").stdout)
@@ -476,28 +500,28 @@ class NetDrvContEnv(NetDrvEpEnv):
return (bpf['pref'], bpf['options']['prog']['id'])
raise Exception("Failed to get BPF prog ID")
+ def _find_bss_map_id(self, prog_id):
+ """Find the .bss map ID for a loaded BPF program."""
+ prog_info = bpftool(f"prog show id {prog_id}", json=True)
+ for map_id in prog_info.get("map_ids", []):
+ map_info = bpftool(f"map show id {map_id}", json=True)
+ if map_info.get("name", "").endswith("bss"):
+ return map_id
+ raise Exception(f"Failed to find .bss map for prog {prog_id}")
+
def _attach_bpf(self):
bpf_obj = self.test_dir / "nk_forward.bpf.o"
if not bpf_obj.exists():
raise KsftSkipEx("BPF prog not found")
- self._tc_ensure_clsact()
+ if self._tc_ensure_clsact():
+ self._tc_clsact_added = True
cmd(f"tc filter add dev {self.ifname} ingress bpf obj {bpf_obj}"
" sec tc/ingress direct-action")
self._tc_attached = True
(self._bpf_prog_pref, self._bpf_prog_id) = self._get_bpf_prog_ids()
- prog_info = bpftool(f"prog show id {self._bpf_prog_id}", json=True)
- map_ids = prog_info.get("map_ids", [])
-
- bss_map_id = None
- for map_id in map_ids:
- map_info = bpftool(f"map show id {map_id}", json=True)
- if map_info.get("name").endswith("bss"):
- bss_map_id = map_id
-
- if bss_map_id is None:
- raise Exception("Failed to find .bss map")
+ bss_map_id = self._find_bss_map_id(self._bpf_prog_id)
ipv6_addr = ipaddress.IPv6Address(self.ipv6_prefix)
ipv6_bytes = ipv6_addr.packed
@@ -505,3 +529,36 @@ class NetDrvContEnv(NetDrvEpEnv):
value = ipv6_bytes + ifindex_bytes
value_hex = ' '.join(f'{b:02x}' for b in value)
bpftool(f"map update id {bss_map_id} key hex 00 00 00 00 value hex {value_hex}")
+
+ def _attach_primary_rx_redirect_bpf(self):
+ """Attach BPF redirect program on the primary netkit ingress."""
+ bpf_obj = self.test_dir / "nk_primary_rx_redirect.bpf.o"
+ if not bpf_obj.exists():
+ raise KsftSkipEx("Primary RX redirect BPF prog not found")
+
+ if self._tc_ensure_clsact(self._nk_host_ifname):
+ self._primary_rx_redirect_clsact_added = True
+ cmd(f"tc filter add dev {self._nk_host_ifname} ingress"
+ f" bpf obj {bpf_obj} sec tc/ingress direct-action")
+ self._primary_rx_redirect_attached = True
+
+ ip(f"-6 route add {self.nk_guest_ipv6}/128 via {self.addr_v['6']}",
+ host=self.remote)
+ self._remote_route_added = True
+
+ filters = json.loads(
+ cmd(f"tc -j filter show dev {self._nk_host_ifname} ingress").stdout)
+ redirect_prog_id = None
+ for bpf in filters:
+ if 'options' not in bpf:
+ continue
+ if bpf['options']['bpf_name'].startswith('nk_primary_rx_redirect'):
+ redirect_prog_id = bpf['options']['prog']['id']
+ break
+ if redirect_prog_id is None:
+ raise Exception("Failed to get primary RX redirect BPF prog ID")
+
+ bss_map_id = self._find_bss_map_id(redirect_prog_id)
+ phys_ifindex_bytes = self.ifindex.to_bytes(4, byteorder='little')
+ value_hex = ' '.join(f'{b:02x}' for b in phys_ifindex_bytes)
+ bpftool(f"map update id {bss_map_id} key hex 00 00 00 00 value hex {value_hex}")
--
2.53.0-Meta
^ permalink raw reply related
* [PATCH net-next v3 6/8] selftests: drv-net: refactor devmem command builders into lib module
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
In-Reply-To: <20260507-tcp-dm-netkit-v3-0-52821445867c@meta.com>
From: Bobby Eshleman <bobbyeshleman@meta.com>
Adding netkit-based devmem tests is a straight-forward copy of devmem
test commands plus some args for the nk cases, so this patch breaks out
these command builders into helpers used by both.
Though we tried to avoid libraries to avoid increasing the barrier of
entry/complexity (see selftests/drivers/net/README.md, section "Avoid
libraries and frameworks"), factoring out these functions seemed like
the lesser of two evils in this case of using the same commands, just
with slightly different args per environment.
I experimented with just having all of the tests in the same file to
avoid having helpers in a library file, but because ksft_run() is
limited to a single call per file, and the new tests will require
different environments (NetDrvContEnv/NetDrvEpEnv), it would have been
necessary to have each test set up its own environment instead of
sharing one for the entire ksft_run() run. This came at the cost of
ballooning the test time (from under 5s to 30s on my test system), so to
strike a balance these tests were placed in separate files so they could
keep a shared environment across a single ksft_run() run shared across
all tests using the same env type (introduced in subsequent patches).
The helpers work transparently with both plain and netkit environments
by inspecting cfg for netkit-specific attributes (netns, nk_queue,
etc...).
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v4:
- Make socat_send() always bind the source; drop its bind= parameter
and the matching bind=not_ns at the run_rx call site.
- Drop socat_send()'s nodelay= arg; have buf_size>0 imply TCP_NODELAY
since they are only meaningful together.
- configure_nic(): stash originals on cfg instead of using defer(); add
paired cleanup_nic() helper. Drop the per-test configure_nic() calls
from run_rx/run_tx/run_tx_chunks/run_rx_hds; the netkit test file
invokes configure_nic/cleanup_nic once around ksft_run().
- make cfg.devmem_supported and cfg.devmem_probed public attrs (no '_')
for sake of linting
- general cleanup of the code, linting fixes
Changes in v3:
- In setup_test, drop the unused cfg.listen_ns = getattr(cfg, 'netns',
None) assignment.
- In run_rx, pass flow_steer=not_ns to ncdevmem_rx and bind=not_ns to
socat_send to avoid changing functionality (we want just a straight
refactor here)
Changes in v2:
- Move require_devmem() into individual test functions so KsftSkipEx goes up to
ksft_run() (Sashiko)
- in ncdevmem_rx(), move -v 7 to take effect for both netns and
non-netns when verify=True
---
tools/testing/selftests/drivers/net/hw/devmem.py | 77 ++------
.../selftests/drivers/net/hw/lib/py/devmem.py | 218 +++++++++++++++++++++
2 files changed, 231 insertions(+), 64 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/hw/devmem.py b/tools/testing/selftests/drivers/net/hw/devmem.py
index ee863e90d1e0..dbc1e6a27b6a 100755
--- a/tools/testing/selftests/drivers/net/hw/devmem.py
+++ b/tools/testing/selftests/drivers/net/hw/devmem.py
@@ -2,91 +2,40 @@
# SPDX-License-Identifier: GPL-2.0
from os import path
-from lib.py import ksft_run, ksft_exit
-from lib.py import ksft_eq, KsftSkipEx
+from lib.py import ksft_run, ksft_exit, ksft_disruptive
from lib.py import NetDrvEpEnv
-from lib.py import bkg, cmd, rand_port, wait_port_listen
-from lib.py import ksft_disruptive
-
-
-def require_devmem(cfg):
- if not hasattr(cfg, "_devmem_probed"):
- probe_command = f"{cfg.bin_local} -f {cfg.ifname}"
- cfg._devmem_supported = cmd(probe_command, fail=False, shell=True).ret == 0
- cfg._devmem_probed = True
-
- if not cfg._devmem_supported:
- raise KsftSkipEx("Test requires devmem support")
+from lib.py.devmem import setup_test, run_rx, run_tx, run_tx_chunks, run_rx_hds
@ksft_disruptive
def check_rx(cfg) -> None:
- require_devmem(cfg)
-
- port = rand_port()
- socat = f"socat -u - TCP{cfg.addr_ipver}:{cfg.baddr}:{port},bind={cfg.remote_baddr}:{port}"
- listen_cmd = f"{cfg.bin_local} -l -f {cfg.ifname} -s {cfg.addr} -p {port} -c {cfg.remote_addr} -v 7"
-
- with bkg(listen_cmd, exit_wait=True) as ncdevmem:
- wait_port_listen(port)
- cmd(f"yes $(echo -e \x01\x02\x03\x04\x05\x06) | \
- head -c 1K | {socat}", host=cfg.remote, shell=True)
-
- ksft_eq(ncdevmem.ret, 0)
+ """Run the devmem RX test."""
+ run_rx(cfg)
@ksft_disruptive
def check_tx(cfg) -> None:
- require_devmem(cfg)
-
- port = rand_port()
- listen_cmd = f"socat -U - TCP{cfg.addr_ipver}-LISTEN:{port}"
-
- with bkg(listen_cmd, host=cfg.remote, exit_wait=True) as socat:
- wait_port_listen(port, host=cfg.remote)
- cmd(f"echo -e \"hello\\nworld\"| {cfg.bin_local} -f {cfg.ifname} -s {cfg.remote_addr} -p {port}", shell=True)
-
- ksft_eq(socat.stdout.strip(), "hello\nworld")
+ """Run the devmem TX test."""
+ run_tx(cfg)
@ksft_disruptive
def check_tx_chunks(cfg) -> None:
- require_devmem(cfg)
-
- port = rand_port()
- listen_cmd = f"socat -U - TCP{cfg.addr_ipver}-LISTEN:{port}"
-
- with bkg(listen_cmd, host=cfg.remote, exit_wait=True) as socat:
- wait_port_listen(port, host=cfg.remote)
- cmd(f"echo -e \"hello\\nworld\"| {cfg.bin_local} -f {cfg.ifname} -s {cfg.remote_addr} -p {port} -z 3", shell=True)
-
- ksft_eq(socat.stdout.strip(), "hello\nworld")
+ """Run the devmem TX chunking test."""
+ run_tx_chunks(cfg)
def check_rx_hds(cfg) -> None:
- """Test HDS splitting across payload sizes."""
- require_devmem(cfg)
-
- for size in [1, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192]:
- port = rand_port()
- listen_cmd = f"{cfg.bin_local} -L -l -f {cfg.ifname} -s {cfg.addr} -p {port}"
-
- with bkg(listen_cmd, exit_wait=True) as ncdevmem:
- wait_port_listen(port)
- cmd(f"dd if=/dev/zero bs={size} count=1 2>/dev/null | " +
- f"socat -b {size} -u - TCP{cfg.addr_ipver}:{cfg.baddr}:{port},nodelay",
- host=cfg.remote, shell=True)
-
- ksft_eq(ncdevmem.ret, 0, f"HDS failed for payload size {size}")
+ """Run the HDS test."""
+ run_rx_hds(cfg)
def main() -> None:
+ """Run the devmem test cases."""
with NetDrvEpEnv(__file__) as cfg:
- cfg.bin_local = path.abspath(path.dirname(__file__) + "/ncdevmem")
- cfg.bin_remote = cfg.remote.deploy(cfg.bin_local)
-
+ setup_test(cfg, path.abspath(path.dirname(__file__) + "/ncdevmem"))
ksft_run([check_rx, check_tx, check_tx_chunks, check_rx_hds],
- args=(cfg, ))
+ args=(cfg,))
ksft_exit()
diff --git a/tools/testing/selftests/drivers/net/hw/lib/py/devmem.py b/tools/testing/selftests/drivers/net/hw/lib/py/devmem.py
new file mode 100644
index 000000000000..d3e7a3645cba
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/lib/py/devmem.py
@@ -0,0 +1,218 @@
+# SPDX-License-Identifier: GPL-2.0
+"""Shared helpers for devmem TCP selftests."""
+
+import re
+
+from net.lib.py import (bkg, cmd, defer, ethtool, rand_port, wait_port_listen,
+ ksft_eq, KsftSkipEx, NetNSEnter, EthtoolFamily,
+ NetdevFamily)
+
+
+def require_devmem(cfg):
+ """Probe ncdevmem on cfg.ifname and SKIP the test if devmem isn't supported."""
+ if not hasattr(cfg, "devmem_probed"):
+ probe_command = f"{cfg.bin_local} -f {cfg.ifname}"
+ cfg.devmem_supported = cmd(probe_command, fail=False, shell=True).ret == 0
+ cfg.devmem_probed = True
+
+ if not cfg.devmem_supported:
+ raise KsftSkipEx("Test requires devmem support")
+
+
+def configure_nic(cfg):
+ """Channels, rings, RSS, queue lease for netkit devmem."""
+ cfg.require_ipver('6')
+ ethnl = EthtoolFamily()
+
+ channels = ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
+ channels = channels['combined-count']
+ if channels < 2:
+ raise KsftSkipEx(
+ 'Test requires NETIF with at least 2 combined channels'
+ )
+
+ rings = ethnl.rings_get({'header': {'dev-index': cfg.ifindex}})
+ cfg.orig_rx_rings = rings['rx']
+ cfg.orig_hds_thresh = rings.get('hds-thresh', 0)
+ cfg.orig_data_split = rings.get('tcp-data-split', 'unknown')
+
+ ethnl.rings_set({'header': {'dev-index': cfg.ifindex},
+ 'tcp-data-split': 'enabled',
+ 'hds-thresh': 0,
+ 'rx': min(64, cfg.orig_rx_rings)})
+
+ cfg.src_queue = channels - 1
+ ethtool(f"-X {cfg.ifname} equal {cfg.src_queue}")
+
+ with NetNSEnter(str(cfg.netns)):
+ netdevnl = NetdevFamily()
+ lease_result = netdevnl.queue_create({
+ "ifindex": cfg.nk_guest_ifindex,
+ "type": "rx",
+ "lease": {
+ "ifindex": cfg.ifindex,
+ "queue": {"id": cfg.src_queue, "type": "rx"},
+ "netns-id": 0,
+ },
+ })
+ cfg.nk_queue = lease_result['id']
+
+
+def cleanup_nic(cfg):
+ """Undo configure_nic() by restoring RSS and ring settings."""
+ ethtool(f"-X {cfg.ifname} default")
+ EthtoolFamily().rings_set({'header': {'dev-index': cfg.ifindex},
+ 'tcp-data-split': cfg.orig_data_split,
+ 'hds-thresh': cfg.orig_hds_thresh,
+ 'rx': cfg.orig_rx_rings})
+
+
+def set_flow_rule(cfg, port):
+ """Install a flow rule steering to src_queue and return the flow rule ID."""
+ output = ethtool(
+ f"-N {cfg.ifname} flow-type tcp6 dst-port {port}"
+ f" action {cfg.src_queue}"
+ ).stdout
+ return int(re.search(r'ID (\d+)', output).group(1))
+
+
+def ncdevmem_rx(cfg, port, verify=True, fail_on_linear=False, flow_steer=False):
+ """Build the ncdevmem RX listener command."""
+ if hasattr(cfg, 'netns'):
+ flow_rule_id = set_flow_rule(cfg, port)
+ defer(ethtool, f"-N {cfg.ifname} delete {flow_rule_id}")
+
+ ifname = cfg.nk_guest_ifname
+ addr = cfg.nk_guest_ipv6
+ extras = [f"-t {cfg.nk_queue}", "-q 1", "-n"]
+ else:
+ ifname = cfg.ifname
+ addr = cfg.addr
+ extras = []
+ if flow_steer:
+ extras.append(f"-c {cfg.remote_addr}")
+
+ if verify:
+ extras.append("-v 7")
+ if fail_on_linear:
+ extras.append("-L")
+
+ parts = [cfg.bin_local, "-l", f"-f {ifname}", f"-s {addr}",
+ f"-p {port}", *extras]
+ return " ".join(parts)
+
+
+def ncdevmem_tx(cfg, port, chunk_size=0):
+ """Build the ncdevmem TX send command."""
+ if hasattr(cfg, 'netns'):
+ ifname = cfg.nk_guest_ifname
+ addr = cfg.remote_addr_v['6']
+ extras = ["-t 0", "-q 1", "-n"]
+ else:
+ ifname = cfg.ifname
+ addr = cfg.remote_addr
+ extras = []
+
+ if chunk_size:
+ extras.append(f"-z {chunk_size}")
+
+ parts = [cfg.bin_local, f"-f {ifname}", f"-s {addr}",
+ f"-p {port}", *extras]
+ return " ".join(parts)
+
+
+def socat_send(cfg, port, buf_size=0):
+ """Socat command for sending to the devmem listener.
+
+ When buf_size > 0, force one TCP segment per write of exactly that size by
+ setting socat's buffer (-b) and disabling Nagle (TCP_NODELAY).
+ """
+ proto = f"TCP{cfg.addr_ipver}"
+
+ if hasattr(cfg, 'netns'):
+ addr = f"[{cfg.nk_guest_ipv6}]"
+ else:
+ addr = cfg.baddr
+
+ suffix = f",bind={cfg.remote_baddr}:{port}"
+
+ buf = ""
+ if buf_size:
+ buf = f"-b {buf_size}"
+ suffix += ",nodelay"
+
+ return f"socat {buf} -u - {proto}:{addr}:{port}{suffix}"
+
+
+def socat_listen(cfg, port):
+ """Socat listen command for TX tests."""
+ return f"socat -U - TCP{cfg.addr_ipver}-LISTEN:{port}"
+
+
+def setup_test(cfg, bin_local):
+ """Stash the local ncdevmem path on cfg and deploy it to the remote."""
+ cfg.bin_local = bin_local
+ cfg.bin_remote = cfg.remote.deploy(cfg.bin_local)
+
+
+def run_rx(cfg):
+ """Run the devmem RX test."""
+ require_devmem(cfg)
+ port = rand_port()
+ socat = socat_send(cfg, port)
+ data_pipe = (f"yes $(echo -e \x01\x02\x03\x04\x05\x06) | head -c 1K"
+ f" | {socat}")
+ netns = getattr(cfg, "netns", None)
+
+ listen_cmd = ncdevmem_rx(cfg, port, flow_steer=not hasattr(cfg, 'netns'))
+ with bkg(listen_cmd, exit_wait=True, ns=netns) as ncdevmem:
+ wait_port_listen(port, proto="tcp", ns=netns)
+ cmd(data_pipe, host=cfg.remote, shell=True)
+ ksft_eq(ncdevmem.ret, 0)
+
+
+def run_tx(cfg):
+ """Run the devmem TX test."""
+ require_devmem(cfg)
+ netns = getattr(cfg, "netns", None)
+ port = rand_port()
+ tx_cmd = ncdevmem_tx(cfg, port)
+ listen_cmd = socat_listen(cfg, port)
+
+ with bkg(listen_cmd, host=cfg.remote, exit_wait=True) as socat:
+ wait_port_listen(port, host=cfg.remote)
+ cmd(f"bash -c 'echo -e \"hello\\nworld\" | {tx_cmd}'", ns=netns, shell=True)
+ ksft_eq(socat.stdout.strip(), "hello\nworld")
+
+
+def run_tx_chunks(cfg):
+ """Run the devmem TX chunking test."""
+ require_devmem(cfg)
+ netns = getattr(cfg, "netns", None)
+ port = rand_port()
+ tx_cmd = ncdevmem_tx(cfg, port, chunk_size=3)
+ listen_cmd = socat_listen(cfg, port)
+
+ with bkg(listen_cmd, host=cfg.remote, exit_wait=True) as socat:
+ wait_port_listen(port, host=cfg.remote)
+ cmd(f"bash -c 'echo -e \"hello\\nworld\" | {tx_cmd}'", ns=netns, shell=True)
+ ksft_eq(socat.stdout.strip(), "hello\nworld")
+
+
+def run_rx_hds(cfg):
+ """Run the HDS test by running devmem RX across a segment size sweep."""
+ require_devmem(cfg)
+ netns = getattr(cfg, "netns", None)
+
+ for size in [1, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192]:
+ port = rand_port()
+
+ listen_cmd = ncdevmem_rx(cfg, port, verify=False,
+ fail_on_linear=True)
+ socat = socat_send(cfg, port, buf_size=size)
+
+ with bkg(listen_cmd, exit_wait=True, ns=netns) as ncdevmem:
+ wait_port_listen(port, proto="tcp", ns=netns)
+ cmd(f"dd if=/dev/zero bs={size} count=1 2>/dev/null | "
+ f"{socat}", host=cfg.remote, shell=True)
+ ksft_eq(ncdevmem.ret, 0, f"HDS failed for payload size {size}")
--
2.53.0-Meta
^ permalink raw reply related
* [PATCH net-next v3 5/8] selftests: drv-net: make attr _nk_guest_ifname public
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
In-Reply-To: <20260507-tcp-dm-netkit-v3-0-52821445867c@meta.com>
From: Bobby Eshleman <bobbyeshleman@meta.com>
Subsequent patches will use the _nk_guest_ifname as a public attr for
setting up devmem. Rename to nk_guest_ifname to avoid angering the
linter about the '_' prefix being used for a non-private attr.
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
tools/testing/selftests/drivers/net/hw/nk_qlease.py | 8 ++++----
tools/testing/selftests/drivers/net/lib/py/env.py | 16 ++++++++--------
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/hw/nk_qlease.py b/tools/testing/selftests/drivers/net/hw/nk_qlease.py
index aa83dc321328..139a91ebd229 100755
--- a/tools/testing/selftests/drivers/net/hw/nk_qlease.py
+++ b/tools/testing/selftests/drivers/net/hw/nk_qlease.py
@@ -71,7 +71,7 @@ def test_iou_zcrx(cfg) -> None:
flow_rule_id = set_flow_rule(cfg)
defer(ethtool, f"-N {cfg.ifname} delete {flow_rule_id}")
- rx_cmd = f"ip netns exec {cfg.netns.name} {cfg.bin_local} -s -p {cfg.port} -i {cfg._nk_guest_ifname} -q {cfg.nk_queue}"
+ rx_cmd = f"ip netns exec {cfg.netns.name} {cfg.bin_local} -s -p {cfg.port} -i {cfg.nk_guest_ifname} -q {cfg.nk_queue}"
tx_cmd = f"{cfg.bin_remote} -c -h {cfg.nk_guest_ipv6} -p {cfg.port} -l 12840"
with bkg(rx_cmd, exit_wait=True):
wait_port_listen(cfg.port, proto="tcp", ns=cfg.netns)
@@ -128,7 +128,7 @@ def test_attach_xdp_with_mp(cfg) -> None:
netdevnl = NetdevFamily()
- rx_cmd = f"ip netns exec {cfg.netns.name} {cfg.bin_local} -s -p {cfg.port} -i {cfg._nk_guest_ifname} -q {cfg.nk_queue}"
+ rx_cmd = f"ip netns exec {cfg.netns.name} {cfg.bin_local} -s -p {cfg.port} -i {cfg.nk_guest_ifname} -q {cfg.nk_queue}"
with bkg(rx_cmd):
wait_port_listen(cfg.port, proto="tcp", ns=cfg.netns)
@@ -178,7 +178,7 @@ def test_destroy(cfg) -> None:
ethtool(f"-X {cfg.ifname} equal {cfg.src_queue}")
defer(ethtool, f"-X {cfg.ifname} default")
- rx_cmd = f"ip netns exec {cfg.netns.name} {cfg.bin_local} -s -p {cfg.port} -i {cfg._nk_guest_ifname} -q {cfg.nk_queue}"
+ rx_cmd = f"ip netns exec {cfg.netns.name} {cfg.bin_local} -s -p {cfg.port} -i {cfg.nk_guest_ifname} -q {cfg.nk_queue}"
rx_proc = cmd(rx_cmd, background=True)
wait_port_listen(cfg.port, proto="tcp", ns=cfg.netns)
@@ -196,7 +196,7 @@ def test_destroy(cfg) -> None:
ip(f"link del dev {cfg._nk_host_ifname}")
kill_timer.join()
cfg._nk_host_ifname = None
- cfg._nk_guest_ifname = None
+ cfg.nk_guest_ifname = None
queue_info = netdevnl.queue_get(
{"ifindex": cfg.ifindex, "id": cfg.src_queue, "type": "rx"}
diff --git a/tools/testing/selftests/drivers/net/lib/py/env.py b/tools/testing/selftests/drivers/net/lib/py/env.py
index 24ce122abd9c..409b41922245 100644
--- a/tools/testing/selftests/drivers/net/lib/py/env.py
+++ b/tools/testing/selftests/drivers/net/lib/py/env.py
@@ -339,7 +339,7 @@ class NetDrvContEnv(NetDrvEpEnv):
def __init__(self, src_path, rxqueues=1, **kwargs):
self.netns = None
self._nk_host_ifname = None
- self._nk_guest_ifname = None
+ self.nk_guest_ifname = None
self._tc_clsact_added = False
self._tc_attached = False
self._bpf_prog_pref = None
@@ -390,7 +390,7 @@ class NetDrvContEnv(NetDrvEpEnv):
netkit_links.sort(key=lambda x: x['ifindex'])
self._nk_host_ifname = netkit_links[1]['ifname']
- self._nk_guest_ifname = netkit_links[0]['ifname']
+ self.nk_guest_ifname = netkit_links[0]['ifname']
self.nk_host_ifindex = netkit_links[1]['ifindex']
self.nk_guest_ifindex = netkit_links[0]['ifindex']
@@ -409,7 +409,7 @@ class NetDrvContEnv(NetDrvEpEnv):
if self._nk_host_ifname:
cmd(f"ip link del dev {self._nk_host_ifname}")
self._nk_host_ifname = None
- self._nk_guest_ifname = None
+ self.nk_guest_ifname = None
if self._init_ns_attached:
cmd("ip netns del init", fail=False)
@@ -448,16 +448,16 @@ class NetDrvContEnv(NetDrvEpEnv):
cmd("ip netns attach init 1")
self._init_ns_attached = True
ip("netns set init 0", ns=self.netns)
- ip(f"link set dev {self._nk_guest_ifname} netns {self.netns.name}")
+ ip(f"link set dev {self.nk_guest_ifname} netns {self.netns.name}")
ip(f"link set dev {self._nk_host_ifname} up")
ip(f"-6 addr add fe80::1/64 dev {self._nk_host_ifname} nodad")
ip(f"-6 route add {self.nk_guest_ipv6}/128 via fe80::2 dev {self._nk_host_ifname}")
ip("link set lo up", ns=self.netns)
- ip(f"link set dev {self._nk_guest_ifname} up", ns=self.netns)
- ip(f"-6 addr add fe80::2/64 dev {self._nk_guest_ifname}", ns=self.netns)
- ip(f"-6 addr add {self.nk_guest_ipv6}/64 dev {self._nk_guest_ifname} nodad", ns=self.netns)
- ip(f"-6 route add default via fe80::1 dev {self._nk_guest_ifname}", ns=self.netns)
+ ip(f"link set dev {self.nk_guest_ifname} up", ns=self.netns)
+ ip(f"-6 addr add fe80::2/64 dev {self.nk_guest_ifname}", ns=self.netns)
+ ip(f"-6 addr add {self.nk_guest_ipv6}/64 dev {self.nk_guest_ifname} nodad", ns=self.netns)
+ ip(f"-6 route add default via fe80::1 dev {self.nk_guest_ifname}", ns=self.netns)
def _tc_ensure_clsact(self):
qdisc = json.loads(cmd(f"tc -j qdisc show dev {self.ifname}").stdout)
--
2.53.0-Meta
^ permalink raw reply related
* [PATCH net-next v3 4/8] selftests: drv-net: ncdevmem: add -n flag to skip NIC configuration
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
In-Reply-To: <20260507-tcp-dm-netkit-v3-0-52821445867c@meta.com>
From: Bobby Eshleman <bobbyeshleman@meta.com>
Add a -n (skip_config) flag that causes ncdevmem to skip NIC
configuration when operating as an RX server. When -n is passed,
ncdevmem skips configuring header split, RSS, and flow steering, as well
as their teardown on exit.
This allows ksft tests to pre-configure the NIC in the host namespace
before launching ncdevmem in the guest namespace. This is needed for
netkit devmem tests where the test harness namespace has direct access
to the NIC and the ncdevmem namespace does not.
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
tools/testing/selftests/drivers/net/hw/ncdevmem.c | 58 +++++++++++++----------
1 file changed, 34 insertions(+), 24 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
index e098d6534c3c..d96e8a3b5a65 100644
--- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
+++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
@@ -93,6 +93,7 @@ static char *port;
static size_t do_validation;
static int start_queue = -1;
static int num_queues = -1;
+static int skip_config;
static char *ifname;
static unsigned int ifindex;
static unsigned int dmabuf_id;
@@ -828,7 +829,7 @@ static struct netdev_queue_id *create_queues(void)
static int do_server(struct memory_buffer *mem)
{
- struct ethtool_rings_get_rsp *ring_config;
+ struct ethtool_rings_get_rsp *ring_config = NULL;
char ctrl_data[sizeof(int) * 20000];
size_t non_page_aligned_frags = 0;
struct sockaddr_in6 client_addr;
@@ -851,27 +852,29 @@ static int do_server(struct memory_buffer *mem)
return -1;
}
- ring_config = get_ring_config();
- if (!ring_config) {
- pr_err("Failed to get current ring configuration");
- return -1;
- }
+ if (!skip_config) {
+ ring_config = get_ring_config();
+ if (!ring_config) {
+ pr_err("Failed to get current ring configuration");
+ return -1;
+ }
- if (configure_headersplit(ring_config, 1)) {
- pr_err("Failed to enable TCP header split");
- goto err_free_ring_config;
- }
+ if (configure_headersplit(ring_config, 1)) {
+ pr_err("Failed to enable TCP header split");
+ goto err_free_ring_config;
+ }
- /* Configure RSS to divert all traffic from our devmem queues */
- if (configure_rss()) {
- pr_err("Failed to configure rss");
- goto err_reset_headersplit;
- }
+ /* Configure RSS to divert all traffic from our devmem queues */
+ if (configure_rss()) {
+ pr_err("Failed to configure rss");
+ goto err_reset_headersplit;
+ }
- /* Flow steer our devmem flows to start_queue */
- if (configure_flow_steering(&server_sin)) {
- pr_err("Failed to configure flow steering");
- goto err_reset_rss;
+ /* Flow steer our devmem flows to start_queue */
+ if (configure_flow_steering(&server_sin)) {
+ pr_err("Failed to configure flow steering");
+ goto err_reset_rss;
+ }
}
if (bind_rx_queue(ifindex, mem->fd, create_queues(), num_queues, &ys)) {
@@ -1052,13 +1055,17 @@ static int do_server(struct memory_buffer *mem)
err_unbind:
ynl_sock_destroy(ys);
err_reset_flow_steering:
- reset_flow_steering();
+ if (!skip_config)
+ reset_flow_steering();
err_reset_rss:
- reset_rss();
+ if (!skip_config)
+ reset_rss();
err_reset_headersplit:
- restore_ring_config(ring_config);
+ if (!skip_config)
+ restore_ring_config(ring_config);
err_free_ring_config:
- ethtool_rings_get_rsp_free(ring_config);
+ if (!skip_config)
+ ethtool_rings_get_rsp_free(ring_config);
return err;
}
@@ -1404,7 +1411,7 @@ int main(int argc, char *argv[])
int is_server = 0, opt;
int ret, err = 1;
- while ((opt = getopt(argc, argv, "Lls:c:p:v:q:t:f:z:")) != -1) {
+ while ((opt = getopt(argc, argv, "Lls:c:p:v:q:t:f:z:n")) != -1) {
switch (opt) {
case 'L':
fail_on_linear = true;
@@ -1436,6 +1443,9 @@ int main(int argc, char *argv[])
case 'z':
max_chunk = atoi(optarg);
break;
+ case 'n':
+ skip_config = 1;
+ break;
case '?':
fprintf(stderr, "unknown option: %c\n", optopt);
break;
--
2.53.0-Meta
^ permalink raw reply related
* [PATCH net-next v3 3/8] net: devmem: support TX over NETMEM_TX_NO_DMA devices
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
In-Reply-To: <20260507-tcp-dm-netkit-v3-0-52821445867c@meta.com>
From: Bobby Eshleman <bobbyeshleman@meta.com>
When a netkit virtual device leases queues from a physical NIC, devmem
TX bindings created on the netkit device must still result in the dmabuf
being mapped for dma by the physical device. This patch accomplishes
this by teaching the bind handler to search for the underlying
DMA-capable device by looking it up via leased rx queues. The function
netdev_find_netmem_tx_dev(), used for finding the underlying DMA-capable
device, can be extended to support other non-netkit NETMEM_TX_NO_DMA
devices in the future if needed.
Additionally, this patch extends validate_xmit_unreadable_skb() to
support the netkit case, where the skb is validated twice: once on the
netkit guest device and again on the physical NIC after BPF redirect or
ip forwarding.
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v3:
- Fix validate_xmit_unreadable_skb() bug for non-devmem
unreadable niovs (should not be dropped)
- Major simplification of validate_xmit_unreadable_skb()
- Fix prematurely released lock in bind-tx handler (Jakub)
Changes in v2:
- In validate_xmit_unreadable_skb() to check netmem_tx mode before
inspecting frags (Jakub)
- Lock bind_dev around netdev_queue_get_dma_dev() when bind_dev !=
netdev to fix lockdep (Sashiko)
---
net/core/dev.c | 3 +++
net/core/devmem.c | 6 +++--
net/core/devmem.h | 9 ++++++--
net/core/netdev-genl.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++----
4 files changed, 72 insertions(+), 9 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index fbe4c328a367..268417c9ef22 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3999,6 +3999,9 @@ static struct sk_buff *validate_xmit_unreadable_skb(struct sk_buff *skb,
if (dev->netmem_tx == NETMEM_TX_NONE)
goto out_free;
+ if (dev->netmem_tx == NETMEM_TX_NO_DMA)
+ goto out;
+
shinfo = skb_shinfo(skb);
if (shinfo->nr_frags > 0) {
diff --git a/net/core/devmem.c b/net/core/devmem.c
index cde4c89bc146..644c286b778f 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -181,7 +181,7 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
}
struct net_devmem_dmabuf_binding *
-net_devmem_bind_dmabuf(struct net_device *dev,
+net_devmem_bind_dmabuf(struct net_device *dev, struct net_device *vdev,
struct device *dma_dev,
enum dma_data_direction direction,
unsigned int dmabuf_fd, struct netdev_nl_sock *priv,
@@ -212,6 +212,7 @@ net_devmem_bind_dmabuf(struct net_device *dev,
}
binding->dev = dev;
+ binding->vdev = vdev;
xa_init_flags(&binding->bound_rxqs, XA_FLAGS_ALLOC);
err = percpu_ref_init(&binding->ref,
@@ -397,7 +398,8 @@ struct net_devmem_dmabuf_binding *net_devmem_get_binding(struct sock *sk,
*/
dst_dev = dst_dev_rcu(dst);
if (unlikely(!dst_dev) ||
- unlikely(dst_dev != READ_ONCE(binding->dev))) {
+ unlikely(dst_dev != READ_ONCE(binding->dev) &&
+ dst_dev != READ_ONCE(binding->vdev))) {
err = -ENODEV;
goto out_unlock;
}
diff --git a/net/core/devmem.h b/net/core/devmem.h
index 1c5c18581fcb..f399632b3c4b 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -19,7 +19,12 @@ struct net_devmem_dmabuf_binding {
struct dma_buf *dmabuf;
struct dma_buf_attachment *attachment;
struct sg_table *sgt;
+ /* Physical NIC that does the actual DMA for this binding. */
struct net_device *dev;
+ /* Virtual device (e.g. netkit) the user called bind-tx on. Must be
+ * NETMEM_TX_NO_DMA.
+ */
+ struct net_device *vdev;
struct gen_pool *chunk_pool;
/* Protect dev */
struct mutex lock;
@@ -84,7 +89,7 @@ struct dmabuf_genpool_chunk_owner {
void __net_devmem_dmabuf_binding_free(struct work_struct *wq);
struct net_devmem_dmabuf_binding *
-net_devmem_bind_dmabuf(struct net_device *dev,
+net_devmem_bind_dmabuf(struct net_device *dev, struct net_device *vdev,
struct device *dma_dev,
enum dma_data_direction direction,
unsigned int dmabuf_fd, struct netdev_nl_sock *priv,
@@ -165,7 +170,7 @@ static inline void net_devmem_put_net_iov(struct net_iov *niov)
}
static inline struct net_devmem_dmabuf_binding *
-net_devmem_bind_dmabuf(struct net_device *dev,
+net_devmem_bind_dmabuf(struct net_device *dev, struct net_device *vdev,
struct device *dma_dev,
enum dma_data_direction direction,
unsigned int dmabuf_fd,
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 4d2c49371cdb..b4d48f3672a5 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -1077,7 +1077,7 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
goto err_rxq_bitmap;
}
- binding = net_devmem_bind_dmabuf(netdev, dma_dev, DMA_FROM_DEVICE,
+ binding = net_devmem_bind_dmabuf(netdev, NULL, dma_dev, DMA_FROM_DEVICE,
dmabuf_fd, priv, info->extack);
if (IS_ERR(binding)) {
err = PTR_ERR(binding);
@@ -1119,9 +1119,43 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
return err;
}
+/* Find the DMA-capable device for a netmem TX binding.
+ *
+ * For NETMEM_TX_DMA devices, return the device itself.
+ * For NETMEM_TX_NO_DMA devices, walk leased RX queues to find the underlying
+ * physical device and return it.
+ */
+static struct net_device *
+netdev_find_netmem_tx_dev(struct net_device *dev)
+{
+ struct netdev_rx_queue *lease_rxq;
+ struct net_device *phys_dev;
+ int i;
+
+ if (dev->netmem_tx == NETMEM_TX_DMA)
+ return dev;
+
+ if (dev->netmem_tx != NETMEM_TX_NO_DMA)
+ return NULL;
+
+ for (i = 0; i < dev->real_num_rx_queues; i++) {
+ lease_rxq = READ_ONCE(__netif_get_rx_queue(dev, i)->lease);
+ if (!lease_rxq)
+ continue;
+
+ phys_dev = lease_rxq->dev;
+ if (netif_device_present(phys_dev) &&
+ phys_dev->netmem_tx == NETMEM_TX_DMA)
+ return phys_dev;
+ }
+
+ return NULL;
+}
+
int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
{
struct net_devmem_dmabuf_binding *binding;
+ struct net_device *bind_dev;
struct netdev_nl_sock *priv;
struct net_device *netdev;
struct device *dma_dev;
@@ -1171,22 +1205,41 @@ int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
goto err_unlock_netdev;
}
- dma_dev = netdev_queue_get_dma_dev(netdev, 0, NETDEV_QUEUE_TYPE_TX);
- binding = net_devmem_bind_dmabuf(netdev, dma_dev, DMA_TO_DEVICE,
- dmabuf_fd, priv, info->extack);
+ bind_dev = netdev_find_netmem_tx_dev(netdev);
+ if (!bind_dev) {
+ err = -EOPNOTSUPP;
+ NL_SET_ERR_MSG(info->extack,
+ "No DMA-capable device found for netmem TX");
+ goto err_unlock_netdev;
+ }
+
+ if (bind_dev != netdev)
+ netdev_lock(bind_dev);
+
+ dma_dev = netdev_queue_get_dma_dev(bind_dev, 0, NETDEV_QUEUE_TYPE_TX);
+
+ binding = net_devmem_bind_dmabuf(bind_dev,
+ bind_dev != netdev ? netdev : NULL,
+ dma_dev, DMA_TO_DEVICE, dmabuf_fd,
+ priv, info->extack);
if (IS_ERR(binding)) {
err = PTR_ERR(binding);
- goto err_unlock_netdev;
+ goto err_unlock_bind_dev;
}
nla_put_u32(rsp, NETDEV_A_DMABUF_ID, binding->id);
genlmsg_end(rsp, hdr);
+ if (bind_dev != netdev)
+ netdev_unlock(bind_dev);
netdev_unlock(netdev);
mutex_unlock(&priv->lock);
return genlmsg_reply(rsp, info);
+err_unlock_bind_dev:
+ if (bind_dev != netdev)
+ netdev_unlock(bind_dev);
err_unlock_netdev:
netdev_unlock(netdev);
err_unlock_sock:
--
2.53.0-Meta
^ permalink raw reply related
* [PATCH net-next v3 2/8] net: netkit: declare NETMEM_TX_NO_DMA mode
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
In-Reply-To: <20260507-tcp-dm-netkit-v3-0-52821445867c@meta.com>
From: Bobby Eshleman <bobbyeshleman@meta.com>
Some virtual devices like netkit (or ifb) never DMA and never touch frag
contents, they just forward the skb to another device. They are unable
to forward unreadable skbs, however, because they fail to pass TX
validation checks on dev->netmem_tx. The existing two-state
NETMEM_TX_NONE / NETMEM_TX_DMA doesn't give the TX validator enough
information to differentiate devices that will attempt DMA on the
unreadable skb from those that will simply route it untouched.
Add a third mode to the enum so drivers can indicate 1) if they have
netmem TX support, and 2) if they do, whether they are DMA-capable:
NETMEM_TX_NO_DMA - pass-through, device never DMAs
Widen dev->netmem_tx from a 1-bit field to 2 bits to fit the new value,
and declare netkit as NETMEM_TX_NO_DMA. Devmem TX support over these
devices comes in a follow-up patch.
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v3:
- net_cachelines/net_device.rst: align the netmem_tx row's type column
with the rest of the table by using "unsigned_long:2" instead of
"unsigned long:2"
- Split this into a distinct patch (Jakub)
---
Documentation/networking/net_cachelines/net_device.rst | 2 +-
Documentation/networking/netmem.rst | 3 +++
Documentation/translations/zh_CN/networking/netmem.rst | 3 +++
drivers/net/netkit.c | 1 +
include/linux/netdevice.h | 7 ++++---
5 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
index 1c19bb7705df..7b3392553fd6 100644
--- a/Documentation/networking/net_cachelines/net_device.rst
+++ b/Documentation/networking/net_cachelines/net_device.rst
@@ -10,7 +10,7 @@ Type Name fastpath_tx_acce
=================================== =========================== =================== =================== ===================================================================================
unsigned_long:32 priv_flags read_mostly __dev_queue_xmit(tx)
unsigned_long:1 lltx read_mostly HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx)
-unsigned long:1 netmem_tx:1; read_mostly
+unsigned_long:2 netmem_tx:2; read_mostly
char name[16]
struct netdev_name_node* name_node
struct dev_ifalias* ifalias
diff --git a/Documentation/networking/netmem.rst b/Documentation/networking/netmem.rst
index 5ccadba4f373..217869d1108d 100644
--- a/Documentation/networking/netmem.rst
+++ b/Documentation/networking/netmem.rst
@@ -99,3 +99,6 @@ Driver TX Requirements
appropriate mode:
- `NETMEM_TX_DMA`: for physical devices that perform DMA.
+
+ - `NETMEM_TX_NO_DMA`: for virtual or passthrough devices that do
+ not DMA, but still support handling of netmem-backed skbs.
diff --git a/Documentation/translations/zh_CN/networking/netmem.rst b/Documentation/translations/zh_CN/networking/netmem.rst
index 9c84423b7528..320f3eacf51b 100644
--- a/Documentation/translations/zh_CN/networking/netmem.rst
+++ b/Documentation/translations/zh_CN/networking/netmem.rst
@@ -92,3 +92,6 @@ dma-mapping API 去处理。
2. 驱动程序应将 `netdev->netmem_tx` 设置为适当的模式：
- `NETMEM_TX_DMA`：适用于执行 DMA 的物理设备。
+
+ - `NETMEM_TX_NO_DMA`：适用于不执行 DMA 的虚拟或透传设备，但仍支持
+ 处理 netmem 支持的 skb。
diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c
index 5e2eecc3165d..0ad6a806d7d5 100644
--- a/drivers/net/netkit.c
+++ b/drivers/net/netkit.c
@@ -466,6 +466,7 @@ static void netkit_setup(struct net_device *dev)
dev->priv_flags |= IFF_NO_QUEUE;
dev->priv_flags |= IFF_DISABLE_NETPOLL;
dev->lltx = true;
+ dev->netmem_tx = NETMEM_TX_NO_DMA;
dev->netdev_ops = &netkit_netdev_ops;
dev->ethtool_ops = &netkit_ethtool_ops;
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 580bccb118a0..11d68e75eb4f 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1791,6 +1791,7 @@ enum netdev_stat_type {
enum netmem_tx_mode {
NETMEM_TX_NONE, /* no netmem TX support */
NETMEM_TX_DMA, /* DMA-capable netmem TX (real HW) */
+ NETMEM_TX_NO_DMA, /* no DMA, e.g. passthrough for virtual devs */
};
enum netdev_reg_state {
@@ -1814,8 +1815,8 @@ enum netdev_reg_state {
* @lltx: device supports lockless Tx. Deprecated for real HW
* drivers. Mainly used by logical interfaces, such as
* bonding and tunnels
- * @netmem_tx: device netmem TX mode (NETMEM_TX_NONE or
- * NETMEM_TX_DMA).
+ * @netmem_tx: device netmem TX mode (NETMEM_TX_NONE, NETMEM_TX_DMA,
+ * or NETMEM_TX_NO_DMA).
*
* @name: This is the first field of the "visible" part of this structure
* (i.e. as seen by users in the "Space.c" file). It is the name
@@ -2138,7 +2139,7 @@ struct net_device {
struct_group(priv_flags_fast,
unsigned long priv_flags:32;
unsigned long lltx:1;
- unsigned long netmem_tx:1;
+ unsigned long netmem_tx:2;
);
const struct net_device_ops *netdev_ops;
const struct header_ops *header_ops;
--
2.53.0-Meta
^ permalink raw reply related
* [PATCH net-next v3 1/8] net: convert netmem_tx flag to enum
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
In-Reply-To: <20260507-tcp-dm-netkit-v3-0-52821445867c@meta.com>
From: Bobby Eshleman <bobbyeshleman@meta.com>
Devices that support netmem TX previously set dev->netmem_tx = true.
This was checked in validate_xmit_unreadable_skb() to drop unreadable
skbs (skbs with dmabuf-backed frags) before they reach drivers that
would mishandle them or devices that would not have the iommu mappings
for them.
A subsequent patch will introduce a third state for virtual devices
that forward unreadable skbs without ever performing DMA on them. To
prepare for that, convert the boolean dev->netmem_tx into an enum:
NETMEM_TX_NONE - no netmem TX support (drop unreadable skbs)
NETMEM_TX_DMA - full support, device does DMA
Update the existing NIC drivers (bnxt, gve, mlx5, fbnic) and the
validators in net/core to use the new enum. No functional change.
Acked-by: Harshitha Ramamurthy <hramamurthy@google.com>
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v3:
- Split NO_DMA changes into subsequent commit (Jakub)
- Move !netdev->netmem_tx -> netdev->netmem_tx ==
NETMEM_TX_NONE conversions to this patch (Jakub)
Changes in v2:
- Squash driver conversion patches (2-5) into patch 1 (Jakub)
---
Documentation/networking/netmem.rst | 5 ++++-
Documentation/translations/zh_CN/networking/netmem.rst | 4 +++-
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 +-
drivers/net/ethernet/google/gve/gve_main.c | 2 +-
drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 2 +-
drivers/net/ethernet/meta/fbnic/fbnic_netdev.c | 2 +-
include/linux/netdevice.h | 8 +++++++-
net/core/dev.c | 2 +-
net/core/netdev-genl.c | 2 +-
9 files changed, 20 insertions(+), 9 deletions(-)
diff --git a/Documentation/networking/netmem.rst b/Documentation/networking/netmem.rst
index b63aded46337..5ccadba4f373 100644
--- a/Documentation/networking/netmem.rst
+++ b/Documentation/networking/netmem.rst
@@ -95,4 +95,7 @@ Driver TX Requirements
netdev@, or reach out to the maintainers and/or almasrymina@google.com for
help adding the netmem API.
-2. Driver should declare support by setting `netdev->netmem_tx = true`
+2. Driver should declare support by setting `netdev->netmem_tx` to the
+ appropriate mode:
+
+ - `NETMEM_TX_DMA`: for physical devices that perform DMA.
diff --git a/Documentation/translations/zh_CN/networking/netmem.rst b/Documentation/translations/zh_CN/networking/netmem.rst
index fe351a240f02..9c84423b7528 100644
--- a/Documentation/translations/zh_CN/networking/netmem.rst
+++ b/Documentation/translations/zh_CN/networking/netmem.rst
@@ -89,4 +89,6 @@ dma-mapping API 去处理。
使用某个还不存在的 netmem API，你可以自行添加并提交到 netdev@，也可以联系维护
人员或者发送邮件至 almasrymina@google.com 寻求帮助。
-2. 驱动程序应通过设置 netdev->netmem_tx = true 来表明自身支持 netmem 功能。
+2. 驱动程序应将 `netdev->netmem_tx` 设置为适当的模式：
+
+ - `NETMEM_TX_DMA`：适用于执行 DMA 的物理设备。
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 8c55874f44ca..ed9c22dc4a5a 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -17120,7 +17120,7 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
dev->queue_mgmt_ops = &bnxt_queue_mgmt_ops_unsupp;
if (BNXT_SUPPORTS_QUEUE_API(bp))
dev->queue_mgmt_ops = &bnxt_queue_mgmt_ops;
- dev->netmem_tx = true;
+ dev->netmem_tx = NETMEM_TX_DMA;
rc = register_netdev(dev);
if (rc)
diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c
index 424d973c97f2..dd2b8f087163 100644
--- a/drivers/net/ethernet/google/gve/gve_main.c
+++ b/drivers/net/ethernet/google/gve/gve_main.c
@@ -2894,7 +2894,7 @@ static int gve_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
goto abort_with_wq;
if (!gve_is_gqi(priv) && !gve_is_qpl(priv))
- dev->netmem_tx = true;
+ dev->netmem_tx = NETMEM_TX_DMA;
err = register_netdev(dev);
if (err)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 5a46870c4b74..fc49aae38807 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -5924,7 +5924,7 @@ static void mlx5e_build_nic_netdev(struct net_device *netdev)
netdev->priv_flags |= IFF_UNICAST_FLT;
- netdev->netmem_tx = true;
+ netdev->netmem_tx = NETMEM_TX_DMA;
netif_set_tso_max_size(netdev, GSO_MAX_SIZE);
mlx5e_set_xdp_feature(priv);
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
index c406a3b56b37..138e522ef9b9 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
@@ -752,7 +752,7 @@ struct net_device *fbnic_netdev_alloc(struct fbnic_dev *fbd)
netdev->netdev_ops = &fbnic_netdev_ops;
netdev->stat_ops = &fbnic_stat_ops;
netdev->queue_mgmt_ops = &fbnic_queue_mgmt_ops;
- netdev->netmem_tx = true;
+ netdev->netmem_tx = NETMEM_TX_DMA;
fbnic_set_ethtool_ops(netdev);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0e1e581efc5a..580bccb118a0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1788,6 +1788,11 @@ enum netdev_stat_type {
NETDEV_PCPU_STAT_DSTATS, /* struct pcpu_dstats */
};
+enum netmem_tx_mode {
+ NETMEM_TX_NONE, /* no netmem TX support */
+ NETMEM_TX_DMA, /* DMA-capable netmem TX (real HW) */
+};
+
enum netdev_reg_state {
NETREG_UNINITIALIZED = 0,
NETREG_REGISTERED, /* completed register_netdevice */
@@ -1809,7 +1814,8 @@ enum netdev_reg_state {
* @lltx: device supports lockless Tx. Deprecated for real HW
* drivers. Mainly used by logical interfaces, such as
* bonding and tunnels
- * @netmem_tx: device support netmem_tx.
+ * @netmem_tx: device netmem TX mode (NETMEM_TX_NONE or
+ * NETMEM_TX_DMA).
*
* @name: This is the first field of the "visible" part of this structure
* (i.e. as seen by users in the "Space.c" file). It is the name
diff --git a/net/core/dev.c b/net/core/dev.c
index 06c195906231..fbe4c328a367 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3996,7 +3996,7 @@ static struct sk_buff *validate_xmit_unreadable_skb(struct sk_buff *skb,
if (likely(skb_frags_readable(skb)))
goto out;
- if (!dev->netmem_tx)
+ if (dev->netmem_tx == NETMEM_TX_NONE)
goto out_free;
shinfo = skb_shinfo(skb);
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index b8f6076d8007..4d2c49371cdb 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -1164,7 +1164,7 @@ int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
goto err_unlock_netdev;
}
- if (!netdev->netmem_tx) {
+ if (netdev->netmem_tx == NETMEM_TX_NONE) {
err = -EOPNOTSUPP;
NL_SET_ERR_MSG(info->extack,
"Driver does not support netmem TX");
--
2.53.0-Meta
^ permalink raw reply related
* [PATCH net-next v3 0/8] net: devmem: support devmem with netkit devices
From: Bobby Eshleman @ 2026-05-08 2:27 UTC (permalink / raw)
To: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan, Alex Shi,
Yanteng Si, Dongliang Mu, Michael Chan, Pavan Chebbi,
Joshua Washington, Harshitha Ramamurthy, Saeed Mahameed,
Tariq Toukan, Mark Bloch, Leon Romanovsky, Alexander Duyck,
kernel-team, Daniel Borkmann, Nikolay Aleksandrov, Shuah Khan
Cc: dw, sdf.kernel, mohsin.bashr, willemb, jiang.kun2, xu.xin16,
wang.yaxin, netdev, linux-doc, linux-kernel, linux-rdma, bpf,
linux-kselftest, Stanislav Fomichev, Mina Almasry, netdev,
linux-doc, linux-kernel, linux-rdma, bpf, linux-kselftest,
Bobby Eshleman
This series enables TCP devmem TX through netkit devices.
Netkit now supports queue leasing. A physical NIC's RX queue can be
leased to a netkit guest interface inside a container namespace. This
gives the container a devmem-capable data path on the RX side (bind-rx,
etc...). On the TX side, the container process binds to its netkit guest
interface and sends traffic that netkit redirects (via BPF or ip
forwarding) to the physical NIC for DMA.
Two things in the existing devmem TX path prevent this from working:
1. validate_xmit_unreadable_skb() requires dev->netmem_tx before it will
forward a dmabuf-backed (unreadable) skb. This protects skbs from
landing on devices that don't have the IOMMU mappings for the backing
dmabuf or that don't speak netmem. Netkit, however, does not support
DMA, doesn't attempt to read unreadable skb pages and so doesn't
break netmem (it is pure skb routing and redirection). It is
functionally capable of routing unreadable skbs, but there is no way
for the TX validation pathway to distinguish between a device that
will actually attempt DMA-ing the skb and another device
(like netkit) that does not DMA but also does not break
netmem.
2. bind_tx_doit uses the bound device as the DMA device. When the user
binds devmem TX to the netkit guest, the bind handler attempts to
create DMA mappings against netkit, which has no DMA capability and
no IOMMU mappings.
This series solves these problems as follows:
1. Extend netmem_tx to two bits, assigned to one of three values:
NETMEM_TX_NONE - netmem not supported
NETMEM_TX_DMA - netmem supported and performs DMA
NETMEM_TX_NO_DMA - netmem supported, but does not DMA
With these bits, phys devices can set NETMEM_TX_DMA and devices like
netkit set NETMEM_TX_NO_DMA. The validation TX path ensures that any
DMA-capable netdev exactly matches the bound device, guaranteeing the
correct mapping of the bound dmabuf. The validation TX path also
allows devices with NETMEM_TX_NO_DMA to pass, knowing these devices
will not misuse netmem or run into IOMMU faults. After redirection or
routing and the skb finally makes its way through the stack to a
physical device's TX path, the above NETMEM_TX_DMA check is performed
again to guarantee the device has the appropriate binding/mappings.
2. On TX bind, the bind handler recognizes NETMEM_TX_NO_DMA devices and
finds the phys TX device and binds to that instead. For the netkit
case, if it has been leased a queue from a DMA-capable device
already, then the bind action is performed on the DMA-capable device
instead and the dmabuf is mapped correctly.
---
Changes in v3:
- Fix validate_xmit_unreadable_skb() logic for non-devmem
unreadable niovs (should not be dropped) (Sashiko)
- Simplify lock handling in bind_tx, no premature release (Jakub)
- split NO_DMA changes into separate patch (Jakub)
- fixed some pylint issues, one required an additional patch ("selftests:
drv-net: make attr _nk_guest_ifname public") to rename a variable from
private to public
- see per-patch changelist for more detailed changes
- Link to v2: https://lore.kernel.org/r/20260504-tcp-dm-netkit-v2-0-56d52ac72fd4@meta.com
Changes in v2:
- Squash driver conversion patches (2-5) into patch 1 (Jakub)
- In validate_xmit_unreadable_skb() to check netmem_tx mode before inspecting
frags (Jakub)
- Lock bind_dev around netdev_queue_get_dma_dev() when bind_dev != netdev to
fix lockdep (Sashiko)
- Move require_devmem() into individual test functions so KsftSkipEx goes up to
ksft_run() (Sashiko)
- Add nk_devmem.py to TEST_PROGS in Makefile (Sashiko)
- Link to v1:
https://lore.kernel.org/all/20260428-tcp-dm-netkit-v1-0-719280eba4d2@meta.com/
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Bobby Eshleman (8):
net: convert netmem_tx flag to enum
net: netkit: declare NETMEM_TX_NO_DMA mode
net: devmem: support TX over NETMEM_TX_NO_DMA devices
selftests: drv-net: ncdevmem: add -n flag to skip NIC configuration
selftests: drv-net: make attr _nk_guest_ifname public
selftests: drv-net: refactor devmem command builders into lib module
selftests: drv-net: add primary_rx_redirect support to NetDrvContEnv
selftests: drv-net: add netkit devmem tests
.../networking/net_cachelines/net_device.rst | 2 +-
Documentation/networking/netmem.rst | 8 +-
.../translations/zh_CN/networking/netmem.rst | 7 +-
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 +-
drivers/net/ethernet/google/gve/gve_main.c | 2 +-
drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 2 +-
drivers/net/ethernet/meta/fbnic/fbnic_netdev.c | 2 +-
drivers/net/netkit.c | 1 +
include/linux/netdevice.h | 11 +-
net/core/dev.c | 5 +-
net/core/devmem.c | 6 +-
net/core/devmem.h | 9 +-
net/core/netdev-genl.c | 65 +++++-
tools/testing/selftests/drivers/net/hw/Makefile | 1 +
tools/testing/selftests/drivers/net/hw/devmem.py | 77 ++------
.../selftests/drivers/net/hw/lib/py/devmem.py | 218 +++++++++++++++++++++
tools/testing/selftests/drivers/net/hw/ncdevmem.c | 58 +++---
.../testing/selftests/drivers/net/hw/nk_devmem.py | 55 ++++++
.../drivers/net/hw/nk_primary_rx_redirect.bpf.c | 39 ++++
.../testing/selftests/drivers/net/hw/nk_qlease.py | 8 +-
tools/testing/selftests/drivers/net/lib/py/env.py | 109 ++++++++---
21 files changed, 549 insertions(+), 138 deletions(-)
---
base-commit: 790ead9394860e7d70c5e0e50a35b243e909a618
change-id: 20260423-tcp-dm-netkit-2bd78b638d30
Best regards,
--
Bobby Eshleman <bobbyeshleman@meta.com>
^ permalink raw reply
* Re: [net-next v39] mctp pcc: Implement MCTP over PCC Transport
From: Jeremy Kerr @ 2026-05-08 2:06 UTC (permalink / raw)
To: Adam Young, Adam Young, Matt Johnston, Andrew Lunn,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: netdev, linux-kernel, Sudeep Holla, Huisong Li
In-Reply-To: <3ca74f8c-fa9f-4a26-a54a-90ab4fa652cb@amperemail.onmicrosoft.com>
Hi Adam,
> > This reads as if you're not updating stats at all, but you do so in
> > mctp_pcc_tx_prepare(). I don't think this comment is necessary - if
> > you really want to mention this, add a comment on the
> > dev_dstats_tx_add() to indicate why you're calling it early.
>
> This comment is in prep for a fairly large change in the PCC layer to
> address it.
>
> This statistic should be reported in tx_done, but cannot be done safely
> yet. The fix is to get tx_done out of a hard-irq handler. I will submit
> that as a follow on changes to mailbox/pcc.c and mctp-pc.c
That's all good, especially if there's a fix coming, but my suggestion
still stands - it would make more sense to comment the stats update in
_prepare(), rather than the absence of a stats update in _done().
Cheers,
Jeremy
^ permalink raw reply
* [PATCH v4 5/5] net/sched: netem: add per-impairment extended statistics
From: Stephen Hemminger @ 2026-05-08 1:55 UTC (permalink / raw)
To: netdev
Cc: jhs, Stephen Hemminger, Jiri Pirko, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Simon Horman, open list
In-Reply-To: <20260508015940.554462-1-stephen@networkplumber.org>
Adds new counters that keep track of when netem applied
impairments (delay, loss, corruption, duplication, reordering).
Add a struct tc_netem_xstats reported via TCA_STATS_APP so that
userspace (tc -s qdisc show) can display per-impairment counters.
The READ_ONCE/WRITE_ONCE pairing here matches the model used
elsewhere for xstats in the qdisc layer.
Also fixes a pre-existing accounting bug: ECN CE-marked packets
were being counted as drops (that is not what other qdisc's do).
Instead, now that there is a proper ecn_marked counter,
the spurious qdisc_qstats_drop() call can be removed.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
Note to reviewers. The READ_ONCE/WRITE_ONCE pattern is allowed.
For some reason current AI prompts are obsessed with complaining
about 64 bit torn read/write on these, since the counters are
informational only, any such complaints are false positive.
Addition to iproute2 will be sent seperately.
include/uapi/linux/pkt_sched.h | 9 +++++++++
net/sched/sch_netem.c | 37 ++++++++++++++++++++++++++++++++--
2 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h
index 66e8072f44df..1c84c8076e22 100644
--- a/include/uapi/linux/pkt_sched.h
+++ b/include/uapi/linux/pkt_sched.h
@@ -569,6 +569,15 @@ struct tc_netem_gemodel {
#define NETEM_DIST_SCALE 8192
#define NETEM_DIST_MAX 16384
+struct tc_netem_xstats {
+ __u64 delayed; /* packets delayed */
+ __u64 dropped; /* packets dropped by loss model */
+ __u64 corrupted; /* packets with bit errors injected */
+ __u64 duplicated; /* duplicate packets generated */
+ __u64 reordered; /* packets sent out of order */
+ __u64 ecn_marked; /* packets ECN CE-marked (not dropped)*/
+};
+
/* DRR */
enum {
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 37df05bf43ee..6d8f4c4cedf3 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -152,6 +152,14 @@ struct netem_sched_data {
u8 state;
} clg;
+ /* Impairment counters */
+ u64 delayed;
+ u64 dropped;
+ u64 corrupted;
+ u64 duplicated;
+ u64 ecn_marked;
+ u64 reordered;
+
/* Cold tail: slot reschedule config and the watchdog timer. */
struct tc_netem_slot slot_config;
struct qdisc_watchdog watchdog;
@@ -462,17 +470,21 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
skb->prev = NULL;
/* Random duplication */
- if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng))
+ if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng)) {
++count;
+ WRITE_ONCE(q->duplicated, q->duplicated + 1);
+ }
/* Drop packet? */
if (loss_event(q)) {
if (q->ecn && INET_ECN_set_ce(skb))
- qdisc_qstats_drop(sch); /* mark packet */
+ WRITE_ONCE(q->ecn_marked, q->ecn_marked + 1);
else
--count;
}
+
if (count == 0) {
+ WRITE_ONCE(q->dropped, q->dropped + 1);
qdisc_qstats_drop(sch);
__qdisc_drop(skb, to_free);
return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
@@ -523,6 +535,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
if (skb->len) {
u32 offset = get_random_u32_below(skb->len);
skb->data[offset] ^= 1 << get_random_u32_below(8);
+ WRITE_ONCE(q->corrupted, q->corrupted + 1);
}
}
@@ -604,12 +617,16 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
cb->time_to_send = now + delay;
++q->counter;
+ if (delay)
+ WRITE_ONCE(q->delayed, q->delayed + 1);
+
tfifo_enqueue(skb, sch);
} else {
/*
* Do re-ordering by putting one out of N packets at the front
* of the queue.
*/
+ WRITE_ONCE(q->reordered, q->reordered + 1);
cb->time_to_send = ktime_get_ns();
q->counter = 0;
@@ -1350,6 +1367,21 @@ static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
return -1;
}
+static int netem_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
+{
+ struct netem_sched_data *q = qdisc_priv(sch);
+ struct tc_netem_xstats st = {
+ .delayed = READ_ONCE(q->delayed),
+ .dropped = READ_ONCE(q->dropped),
+ .corrupted = READ_ONCE(q->corrupted),
+ .duplicated = READ_ONCE(q->duplicated),
+ .reordered = READ_ONCE(q->reordered),
+ .ecn_marked = READ_ONCE(q->ecn_marked),
+ };
+
+ return gnet_stats_copy_app(d, &st, sizeof(st));
+}
+
static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
struct sk_buff *skb, struct tcmsg *tcm)
{
@@ -1412,6 +1444,7 @@ static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
.destroy = netem_destroy,
.change = netem_change,
.dump = netem_dump,
+ .dump_stats = netem_dump_stats,
.owner = THIS_MODULE,
};
MODULE_ALIAS_NET_SCH("netem");
--
2.53.0
^ permalink raw reply related
* [PATCH v4 4/5] net/sched: netem: handle multi-segment skb in corruption
From: Stephen Hemminger @ 2026-05-08 1:55 UTC (permalink / raw)
To: netdev
Cc: jhs, Stephen Hemminger, Jiri Pirko, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Simon Horman, open list
In-Reply-To: <20260508015940.554462-1-stephen@networkplumber.org>
The packet corruption code only flipped bits in the linear
header portion of the skb, skipping corruption when
skb_headlen() was zero.
Linearize the whole skb if necessary before corruption.
Extends d64cb81dcbd5 ("net/sched: sch_netem: fix out-of-bounds access
in packet corruption") with a more general solution.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
net/sched/sch_netem.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 53bdfa77ee2d..37df05bf43ee 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -513,16 +513,17 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
qdisc_qstats_drop(sch);
goto finish_segs;
}
- if (skb->ip_summed == CHECKSUM_PARTIAL &&
- skb_checksum_help(skb)) {
+ if (skb_linearize(skb) ||
+ (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))) {
qdisc_drop(skb, sch, to_free);
skb = NULL;
goto finish_segs;
}
- if (skb_headlen(skb))
- skb->data[get_random_u32_below(skb_headlen(skb))] ^=
- 1 << get_random_u32_below(8);
+ if (skb->len) {
+ u32 offset = get_random_u32_below(skb->len);
+ skb->data[offset] ^= 1 << get_random_u32_below(8);
+ }
}
if (unlikely(sch->q.qlen >= sch->limit)) {
--
2.53.0
^ permalink raw reply related
* [PATCH v4 3/5] net/sched: netem: replace pr_info with netlink extack error messages
From: Stephen Hemminger @ 2026-05-08 1:55 UTC (permalink / raw)
To: netdev
Cc: jhs, Stephen Hemminger, Jiri Pirko, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Simon Horman, open list
In-Reply-To: <20260508015940.554462-1-stephen@networkplumber.org>
Use netlink extack to report errors instead of sending them
to the kernel log with pr_info(). The error message can them be seen
with tc commands; and avoids log spam.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
net/sched/sch_netem.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 2b0b5c032e70..53bdfa77ee2d 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -921,7 +921,8 @@ static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
}
-static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
+static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr,
+ struct netlink_ext_ack *extack)
{
const struct nlattr *la;
int rem;
@@ -934,7 +935,8 @@ static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
const struct tc_netem_gimodel *gi = nla_data(la);
if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
- pr_info("netem: incorrect gi model size\n");
+ NL_SET_ERR_MSG_ATTR(extack, la,
+ "netem: incorrect gi model size");
return -EINVAL;
}
@@ -953,7 +955,8 @@ static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
const struct tc_netem_gemodel *ge = nla_data(la);
if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
- pr_info("netem: incorrect ge model size\n");
+ NL_SET_ERR_MSG_ATTR(extack, la,
+ "netem: incorrect ge model size");
return -EINVAL;
}
@@ -967,7 +970,8 @@ static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
}
default:
- pr_info("netem: unknown loss type %u\n", type);
+ NL_SET_ERR_MSG_ATTR_FMT(extack, la,
+ "netem: unknown loss type %u", type);
return -EINVAL;
}
}
@@ -990,19 +994,21 @@ static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
};
static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
- const struct nla_policy *policy, int len)
+ const struct nla_policy *policy, int len,
+ struct netlink_ext_ack *extack)
{
int nested_len = nla_len(nla) - NLA_ALIGN(len);
if (nested_len < 0) {
- pr_info("netem: invalid attributes len %d\n", nested_len);
+ NL_SET_ERR_MSG_FMT(extack, "netem: invalid attributes len %d < %d",
+ nla_len(nla), NLA_ALIGN(len));
return -EINVAL;
}
if (nested_len >= nla_attr_size(0))
return nla_parse_deprecated(tb, maxtype,
nla_data(nla) + NLA_ALIGN(len),
- nested_len, policy, NULL);
+ nested_len, policy, extack);
memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
return 0;
@@ -1057,7 +1063,7 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt,
int ret;
qopt = nla_data(opt);
- ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
+ ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt), extack);
if (ret < 0)
return ret;
@@ -1097,7 +1103,7 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt,
old_loss_model = q->loss_model;
if (tb[TCA_NETEM_LOSS]) {
- ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
+ ret = get_loss_clg(q, tb[TCA_NETEM_LOSS], extack);
if (ret) {
q->loss_model = old_loss_model;
q->clg = old_clg;
@@ -1193,8 +1199,6 @@ static int netem_init(struct Qdisc *sch, struct nlattr *opt,
prandom_seed_state(&q->prng.prng_state, q->prng.seed);
ret = netem_change(sch, opt, extack);
- if (ret)
- pr_info("netem: change failed\n");
return ret;
}
--
2.53.0
^ permalink raw reply related
* [PATCH v4 2/5] net/sched: netem: remove useless VERSION
From: Stephen Hemminger @ 2026-05-08 1:55 UTC (permalink / raw)
To: netdev
Cc: jhs, Stephen Hemminger, Jiri Pirko, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Simon Horman, open list
In-Reply-To: <20260508015940.554462-1-stephen@networkplumber.org>
The version printed was never updated and kernel version is
better indication of what is fixed or not.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
net/sched/sch_netem.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 616d33879fdc..2b0b5c032e70 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -27,8 +27,6 @@
#include <net/pkt_sched.h>
#include <net/inet_ecn.h>
-#define VERSION "1.3"
-
/* Network Emulation Queuing algorithm.
====================================
@@ -1413,16 +1411,15 @@ static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
};
MODULE_ALIAS_NET_SCH("netem");
-
static int __init netem_module_init(void)
{
- pr_info("netem: version " VERSION "\n");
return register_qdisc(&netem_qdisc_ops);
}
static void __exit netem_module_exit(void)
{
unregister_qdisc(&netem_qdisc_ops);
}
+
module_init(netem_module_init)
module_exit(netem_module_exit)
MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related
* [PATCH v4 1/5] net/sched: netem: reorder struct netem_sched_data
From: Stephen Hemminger @ 2026-05-08 1:55 UTC (permalink / raw)
To: netdev
Cc: jhs, Stephen Hemminger, Jiri Pirko, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Simon Horman, open list
In-Reply-To: <20260508015940.554462-1-stephen@networkplumber.org>
The current layout of struct netem_sched_data can be improved
by optimizing cache locality, compacting data types (use u8
for enum) and eliminating unused elements.
Reorganize the struct as follows:
- Cacheline 0 holds the tfifo state (t_root/t_head/t_tail/t_len),
counter, and the unconditional enqueue scalars
latency/jitter/rate/gap/loss.
- Cacheline 1 holds the remaining zero-check scalars
(duplicate/reorder/corrupt/ecn), all five crndstate correlation
structures, and loss_model.
- Cacheline 2 holds prng, delay_dist, the slot dequeue state,
slot_dist, and the inner classful qdisc pointer.
- Rate-shaping fields, q->limit (config-only; the fast path reads
sch->limit), and the CLG Markov state move to the warm tail.
- tc_netem_slot slot_config and qdisc_watchdog (only consulted on
slot reschedule and watchdog wake) move to the cold tail.
Also reorder struct clgstate to place the u8 state member after the
u32 transition probabilities. This removes the 3-byte interior hole
without changing the struct's size.
Should have no functional change.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
net/sched/sch_netem.c | 123 +++++++++++++++++++++---------------------
1 file changed, 63 insertions(+), 60 deletions(-)
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index bc18e1976b6e..616d33879fdc 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -71,89 +71,92 @@ struct disttable {
s16 table[] __counted_by(size);
};
-struct netem_sched_data {
- /* internal t(ime)fifo qdisc uses t_root and sch->limit */
- struct rb_root t_root;
-
- /* a linear queue; reduces rbtree rebalancing when jitter is low */
- struct sk_buff *t_head;
- struct sk_buff *t_tail;
-
- u32 t_len;
-
- /* optional qdisc for classful handling (NULL at netem init) */
- struct Qdisc *qdisc;
-
- struct qdisc_watchdog watchdog;
+/* Loss models */
+enum {
+ CLG_RANDOM,
+ CLG_4_STATES,
+ CLG_GILB_ELL,
+};
- s64 latency;
- s64 jitter;
+/* States in GE model */
+enum {
+ GOOD_STATE = 1,
+ BAD_STATE,
+};
- u32 loss;
- u32 ecn;
- u32 limit;
- u32 counter;
- u32 gap;
- u32 duplicate;
- u32 reorder;
- u32 corrupt;
- u64 rate;
- s32 packet_overhead;
- u32 cell_size;
- struct reciprocal_value cell_size_reciprocal;
- s32 cell_overhead;
+/* States in 4 state model */
+enum {
+ TX_IN_GAP_PERIOD = 1,
+ TX_IN_BURST_PERIOD,
+ LOST_IN_GAP_PERIOD,
+ LOST_IN_BURST_PERIOD,
+};
+struct netem_sched_data {
+ /* Cacheline 0: tfifo state and per-packet enqueue/dequeue scalars. */
+ struct rb_root t_root;
+ struct sk_buff *t_head;
+ struct sk_buff *t_tail;
+ u32 t_len;
+ u32 counter;
+ s64 latency;
+ s64 jitter;
+ u64 rate;
+ u32 gap;
+ u32 loss;
+
+ /* Cacheline 1: zero-check scalars and correlation states. */
+ u32 duplicate;
+ u32 reorder;
+ u32 corrupt;
+ u32 ecn;
struct crndstate {
u32 last;
u32 rho;
} delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
+ u8 loss_model;
- struct prng {
+ /* Cacheline 2: PRNG, distribution tables, slot dequeue state etc. */
+ struct prng {
u64 seed;
struct rnd_state prng_state;
} prng;
+ struct disttable *delay_dist;
+ struct slotstate {
+ u64 slot_next;
+ s32 packets_left;
+ s32 bytes_left;
+ } slot;
+ struct disttable *slot_dist;
+ struct Qdisc *qdisc;
- struct disttable *delay_dist;
-
- enum {
- CLG_RANDOM,
- CLG_4_STATES,
- CLG_GILB_ELL,
- } loss_model;
-
- enum {
- TX_IN_GAP_PERIOD = 1,
- TX_IN_BURST_PERIOD,
- LOST_IN_GAP_PERIOD,
- LOST_IN_BURST_PERIOD,
- } _4_state_model;
-
- enum {
- GOOD_STATE = 1,
- BAD_STATE,
- } GE_state_model;
+ /*
+ * Warm: rate-shaping parameters (only read when rate != 0) and
+ * configuration-only fields. The fast path reads sch->limit, not
+ * q->limit.
+ */
+ s32 packet_overhead;
+ u32 cell_size;
+ struct reciprocal_value cell_size_reciprocal;
+ s32 cell_overhead;
+ u32 limit;
/* Correlated Loss Generation models */
struct clgstate {
- /* state of the Markov chain */
- u8 state;
-
/* 4-states and Gilbert-Elliot models */
u32 a1; /* p13 for 4-states or p for GE */
u32 a2; /* p31 for 4-states or r for GE */
u32 a3; /* p32 for 4-states or h for GE */
u32 a4; /* p14 for 4-states or 1-k for GE */
u32 a5; /* p23 used only in 4-states */
- } clg;
- struct tc_netem_slot slot_config;
- struct slotstate {
- u64 slot_next;
- s32 packets_left;
- s32 bytes_left;
- } slot;
+ /* state of the Markov chain */
+ u8 state;
+ } clg;
- struct disttable *slot_dist;
+ /* Cold tail: slot reschedule config and the watchdog timer. */
+ struct tc_netem_slot slot_config;
+ struct qdisc_watchdog watchdog;
};
/* Time stamp put into socket buffer control block
--
2.53.0
^ permalink raw reply related
* [PATCH v4 0/5] net/sched: netem: fixes and improvements
From: Stephen Hemminger @ 2026-05-08 1:55 UTC (permalink / raw)
To: netdev; +Cc: jhs, Stephen Hemminger
This is a collection of improvements to netem found while
investigating the fixes now in net tree.
v4 - address Sashiko review feedback
Stephen Hemminger (5):
net/sched: netem: reorder struct netem_sched_data
net/sched: netem: remove useless VERSION
net/sched: netem: replace pr_info with netlink extack error messages
net/sched: netem: handle multi-segment skb in corruption
net/sched: netem: add per-impairment extended statistics
include/uapi/linux/pkt_sched.h | 9 ++
net/sched/sch_netem.c | 202 ++++++++++++++++++++-------------
2 files changed, 129 insertions(+), 82 deletions(-)
--
2.53.0
^ permalink raw reply
* Re: [PATCH v2 0/7] seg6: add SRv6 Mobile User Plane (RFC 9433) behaviors
From: Andrea Mayer @ 2026-05-08 1:32 UTC (permalink / raw)
To: Yuya Kusakabe
Cc: Jakub Kicinski, David S. Miller, Eric Dumazet, Paolo Abeni,
Simon Horman, Shuah Khan, Jonathan Corbet, Shuah Khan,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org,
Justin Iurman, stefano.salsano, Andrea Mayer
In-Reply-To: <20260504182833.344d7b33@kernel.org>
On Mon, 4 May 2026 18:28:33 -0700
Jakub Kicinski <kuba@kernel.org> wrote:
> On Tue, 5 May 2026 10:22:58 +0900 Yuya Kusakabe wrote:
> > Just to confirm the workflow you'd prefer: should I repost the
> > current series immediately as [PATCH RFC net-next v3 ...], or wait
> > for technical review on v2 to land and fold it into a v3 RFC?
>
> Let's wait for reviews (adding Justin to CC as well FWIW)
Hi Yuya,
just a heads-up: I am going through the series (kernel and iproute2)
and will send detailed comments within the next few days. It is a
substantial addition so I want to take the time to review it properly.
Thanks,
Andrea
^ permalink raw reply
* [syzbot] [wireless?] WARNING in wiphy_register (5)
From: syzbot @ 2026-05-08 0:30 UTC (permalink / raw)
To: johannes, linux-kernel, linux-wireless, netdev, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 2281958e6007 Merge tag 'wireless-next-2026-05-06' of https..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=139f656a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f2b487b72ffad035
dashboard link: https://syzkaller.appspot.com/bug?extid=2002864e6c6895cb0ac3
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1452fb48580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=179f656a580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4df17f60254b/disk-2281958e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1e93157edd25/vmlinux-2281958e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/60dbf6a0a81c/bzImage-2281958e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2002864e6c6895cb0ac3@syzkaller.appspotmail.com
------------[ cut here ]------------
(wiphy->interface_modes & BIT(NL80211_IFTYPE_NAN_DATA)) && (!wiphy->nan_capa.phy.ht.ht_supported || wiphy->n_radio > 1)
WARNING: net/wireless/core.c:885 at wiphy_register+0x58a/0x2fe0 net/wireless/core.c:884, CPU#0: syz.0.17/5835
Modules linked in:
CPU: 0 UID: 0 PID: 5835 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:wiphy_register+0x58a/0x2fe0 net/wireless/core.c:884
Code: 00 00 e8 49 8f d4 f6 90 0f 0b 90 e9 67 0a 00 00 e8 3b 8f d4 f6 e9 59 0a 00 00 e8 31 8f d4 f6 e9 eb 00 00 00 e8 27 8f d4 f6 90 <0f> 0b 90 e9 45 0a 00 00 44 89 f8 24 06 0f b6 d8 31 ff 89 de e8 0d
RSP: 0018:ffffc90003236860 EFLAGS: 00010293
RAX: ffffffff8af13fe2 RBX: 0000000000000004 RCX: ffff88802ed60000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: ffffc900032369f0 R08: ffff8880582b0faf R09: 1ffff1100b0561f5
R10: dffffc0000000000 R11: ffffed100b0561f6 R12: ffff8880582b0740
R13: dffffc0000000000 R14: ffffffff8d002990 R15: ffff8880582b0804
FS: 0000555593855500(0000) GS:ffff888125289000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007eff2e872700 CR3: 0000000075672000 CR4: 00000000003526f0
Call Trace:
<TASK>
ieee80211_register_hw+0x3c53/0x4910 net/mac80211/main.c:1627
mac80211_hwsim_new_radio+0x3327/0x57e0 drivers/net/wireless/virtual/mac80211_hwsim_main.c:6047
hwsim_new_radio_nl+0xe20/0x26e0 drivers/net/wireless/virtual/mac80211_hwsim_main.c:6832
genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2551
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1895
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x972/0x9f0 net/socket.c:2698
___sys_sendmsg+0x2a5/0x360 net/socket.c:2752
__sys_sendmsg net/socket.c:2784 [inline]
__do_sys_sendmsg net/socket.c:2789 [inline]
__se_sys_sendmsg net/socket.c:2787 [inline]
__x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2787
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7eff2e99cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd72c5edf8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007eff2ec15fa0 RCX: 00007eff2e99cdd9
RDX: 0000000000000000 RSI: 0000200000000100 RDI: 0000000000000003
RBP: 00007eff2ea32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007eff2ec15fac R14: 00007eff2ec15fa0 R15: 00007eff2ec15fa0
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply
* [PATCH net] sctp: revalidate list cursor after sctp_sendmsg_to_asoc() in SCTP_SENDALL
From: joycathacker @ 2026-05-08 0:14 UTC (permalink / raw)
To: marcelo.leitner, lucien.xin
Cc: davem, edumazet, kuba, pabeni, horms, linux-sctp, netdev,
linux-kernel, security, Ben Morris, stable
From: Ben Morris <bmorris@anthropic.com>
The SCTP_SENDALL path in sctp_sendmsg() iterates ep->asocs with
list_for_each_entry_safe(), which caches the next entry in @tmp before
the loop body runs. The body calls sctp_sendmsg_to_asoc(), which may
drop the socket lock inside sctp_wait_for_sndbuf().
While the lock is dropped, another thread can SCTP_SOCKOPT_PEELOFF the
association cached in @tmp, migrating it to a new endpoint via
sctp_sock_migrate() (list_del_init() + list_add_tail() to
newep->asocs), and optionally close the new socket which frees the
association via kfree_rcu(). The cached @tmp can also be freed by a
network ABORT for that association, processed in softirq while the
lock is dropped.
sctp_wait_for_sndbuf() revalidates @asoc (the current entry) on re-lock
via the "sk != asoc->base.sk" and "asoc->base.dead" checks, but nothing
revalidates @tmp. After a successful return, the iterator advances to
the stale @tmp, yielding either a use-after-free (if the peeled socket
was closed) or a list-walk onto the new endpoint's list head (type
confusion of &newep->asocs as a struct sctp_association *).
Both are reachable from CapEff=0; the type-confusion path gives
controlled indirect call via the outqueue.sched->init_sid pointer.
Fix by re-deriving @tmp from @asoc after sctp_sendmsg_to_asoc()
returns. @asoc is known to still be on ep->asocs at that point: the
only callers that list_del an association from ep->asocs are
sctp_association_free() (which sets asoc->base.dead) and
sctp_assoc_migrate() (which changes asoc->base.sk), and
sctp_wait_for_sndbuf() checks both under the lock before any
successful return; a tripped check propagates as err < 0 and the loop
bails before the re-derive.
The SCTP_ABORT path in sctp_sendmsg_check_sflags() returns 0 and the
loop hits 'continue' before sctp_sendmsg_to_asoc() is ever called, so
the @tmp cached by list_for_each_entry_safe() still covers the
lock-held free that ba59fb027307 ("sctp: walk the list of asoc
safely") was added for.
Fixes: 4910280503f3 ("sctp: add support for snd flag SCTP_SENDALL process in sendmsg")
Cc: stable@vger.kernel.org
Assisted-by: claude:mythos
Signed-off-by: Ben Morris <bmorris@anthropic.com>
---
net/sctp/socket.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 58d0d9747f0b..1d2568bb6bc2 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1986,6 +1986,15 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
goto out_unlock;
iov_iter_revert(&msg->msg_iter, err);
+
+ /* sctp_sendmsg_to_asoc() may have released the socket
+ * lock (sctp_wait_for_sndbuf), during which other
+ * associations on ep->asocs could have been peeled
+ * off or freed. @asoc itself is revalidated by the
+ * base.dead and base.sk checks in sctp_wait_for_sndbuf,
+ * so re-derive the cached cursor from it.
+ */
+ tmp = list_next_entry(asoc, asocs);
}
goto out_unlock;
--
2.43.0
^ permalink raw reply related
* Re: [PATCH net] rtnetlink: add RTEXT_FILTER_TERSE_DUMP support
From: Kuniyuki Iwashima @ 2026-05-08 0:02 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Simon Horman,
David Ahern, netdev, eric.dumazet
In-Reply-To: <20260507174547.4125412-1-edumazet@google.com>
On Thu, May 7, 2026 at 10:45 AM Eric Dumazet <edumazet@google.com> wrote:
>
> iproute2 can spend considerable amount of time in ll_init_map()
> or ll_link_get() to dump verbose netdev attributes, contributing
> to RTNL pressure.
>
> Add RTEXT_FILTER_TERSE_DUMP new flag so that rtnl_fill_ifinfo()
> limits its output to:
>
> - struct nlmsghdr
> - IFLA_IFNAME
> - IFLA_PROP_LIST
>
> We can later avoid using RTNL when RTEXT_FILTER_TERSE_DUMP
> is requested, as none of these attributes need RTNL.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
^ permalink raw reply
* Re: [Intel-wired-lan] [PATCH net-next] e1000e: ethtool: add get_channels support
From: Jacob Keller @ 2026-05-07 23:49 UTC (permalink / raw)
To: Jakub Kicinski, Jon Kohler
Cc: Tony Nguyen, Przemek Kitszel, Andrew Lunn, David S. Miller,
Eric Dumazet, Paolo Abeni, intel-wired-lan@lists.osuosl.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
In-Reply-To: <20260504182635.39e1b7a6@kernel.org>
On 5/4/2026 6:26 PM, Jakub Kicinski wrote:
> On Tue, 5 May 2026 01:12:29 +0000 Jon Kohler wrote:
>>> On May 4, 2026, at 9:06 PM, Jakub Kicinski <kuba@kernel.org> wrote:
>>>
>>> On Tue, 5 May 2026 00:59:40 +0000 Jon Kohler wrote:
>> [...]
>> [...]
>> [...]
>>>>
>>>> Perhaps, but I’m not sure that is a guarantee. A good relevant example
>>>> is when I added get_channels support to enic, which supports all sorts
>>>> of channels, so I don’t think EOPNOTSUP can be 100% consider reliable
>>>> in that case. Meaning, if it just so happens that the original author(s)
>>>> didn't put in get_channels, that doesn’t necessarily mean there is only
>>>> one queue.
>>>>
>>>> And in this case, there is an "other" queue as as well too, as far as
>>>> I can tell, so the output is at least semi-interesting.
>>>
>>> Sorry I wasn't clear enough - if you have an actual, real life use case
>>> why you need queue count of 1 to be explicitly reported - please explain
>>> it and put it in the commit message.
>>>
>>> If you don't - please don't send patches for the sake of it.
>>
>> Ah, ok, sorry I misread your message, this isn’t a patch for the sake of
>> a patch. Long story short, we’ve got a user space part of our control plane
>> that reads in the output of ethtool -l as part of some broader queue
>> management code. On systems with an e1000e device present, this specific
>> component goes into a crash loop as it expects all NIC(s) to at least
>> give it some sort of output.
>>
>> That crash loop is easy enough to fix to ignore unsupported outputs;
>> however, my thought here is a simply defense in depth fixup, especially
>> since the kernel patch is quite trivial.
>
> Got it, thanks for explaining.
>
> My concern is that if we are expected to always report channel counts
> we're signing up for a major whack-a-mole with the existing drivers.
> Most drivers don't implement it. The networking stack does report
> the number of queues the device asked for via rtnetlink:
>
> ip -j -d li show dev $ifc | jq '.[].num_rx_queues'
>
> but in your case I'd personally lean towards user space fix.
Yea, unless we wanted to modify the core ethtool logic so that a driver
without .get_channels would report a single queue.. but I don't know if
that's very accurate.
Still, I think in this case it makes sense to just fix the userspace to
handle EOPNOTSUPP instead of assuming it will be available.
Thanks,
Jake
^ permalink raw reply
page: next (older) | prev (newer) | latest
- recent:[subjects (threaded)|topics (new)|topics (active)]
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox