- Specify BUS_DMA_NOWAIT for bus_dmamap_load() on rx refill, since
callbacks are not supposed to be used.
- Match tso/non-tso tags to corresponding tx map operations. Create
separate tso maps for tx descriptors. In particular, do not use
non-tso tag to load, unload, or destroy a map created with tso tag.
- Add missed bus_dmamap_sync() calls.
Submitted by: marius.
Reported and tested by: pho
Reviewed by: marius
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
iflib_init_locked() assumes that iflib_stop() has been called, however,
it is not called for suspend. iflib_if_init_locked() calls stop then init,
so fixes the problem.
This was causing errors after a resume from suspend.
PR: 224059
Reported by: zeising
MFC after: 1 week
Sponsored by: Limelight Networks
r336560 was supposed to restore pre-r323954 behaviour when tx_abdicate is
not set (the default case). However, it appears that rather than the drainage
check being made conditional on tx_abdicate being set, it was duplicated
so it occured twice if tx_abdicate was set and once if it was not.
Now when !tx_abdicate, drainage is only checked if the doorbell isn't
pending.
Reported by: lev
MFC after: 1 week
Sponsored by: Limelight Networks
- Remove the complex mechanism to choose between using busdma
and raw pmap_kextract at runtime. The reduced complexity makes
the code easier to read and maintain.
- Fix a bug in the small packet receive path where clusters were
repeatedly mapped but never unmapped. We now store the cluster's
bus address and avoid re-mapping the cluster each time a small
packet is received.
This patch fixes bugs I've seen where ixl(4) will not even
respond to ping without seeing DMAR faults.
I see a small improvement (14%) on packet forwarding tests using
a Haswell based Xeon E5-2697 v3. Olivier sees a small
regression (-3% to -6%) with lower end hardware.
Reviewed by: mmacy
Not objected to by: sbruno
MFC after: 8 weeks
Sponsored by: Netflix, Inc
Differential Revision: https://reviews.freebsd.org/D17901
iflib_stop() was not resetting the rxq completion queue state variables.
This meant that for any driver that has receive completion queues, after a
reinit, iflib would start asking what's available on the rx side starting at
whatever the completion queue index was prior to the stop, instead of at 0.
Submitted by: pkelsey
Reported by: pkelsey
MFC after: 3 days
Sponsored by: Limelight Networks
Ensure that any time CSUM_IP_TSO or CSUM_IP6_TSO is set that the corresponding
CSUM_IP6?_TCP / CSUM_IP flags are also set.
Rather than requireing drivers to bake-in an understanding that TSO implies
checksum offloads, make it explicit.
This change requires us to move the IFLIB_NEED_ZERO_CSUM implementation to
ensure it's zeroed for TSO.
Reported by: Jacob Keller <jacob.e.keller@intel.com>
MFC after: 1 week
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D17801
r333502 removed initialization of ifc_nhwtxqs, and it's not clear
there's a need to copy it into the struct iflib_ctx at all. Use
ctx->ifc_sctx->isc_ntxqs instead.
Further, iflib_stop() did not clear the last ring in the case where
isc_nfl != isc_nrxqs (such as when IFLIB_HAS_RXCQ is set). Use
ctx->ifc_sctx->isc_nrxqs here instead of isc_nfl.
Reported by: pkelsey
Reviewed by: pkelsey
MFC after: 3 days
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D17979
r338838 attempted to fix issues with rxcsum and rxcsum6.
However, the rxcsum bits were set as though if_setcapenablebit() was
being called, not if_togglecapenable() which is in use. As a result,
it was not possible to disable rxcsum when rxcsum6 was supported.
PR: 233004
Reported by: lev
Reviewed by: lev
MFC after: 3 days
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D17881
That commit is causing kernel panics in em(4), so this will be reverted
until those are fixed.
Reported by: ae@, pho@, et al
Sponsored by: Intel Corporation
The taskqgroup_detach function does not check if task is already enqueued when
detaching it. This may lead to kernel panic if enqueued task starts after
context state lock is destroyed. Ensure that the already enqueued admin tasks
are executed before detaching them.
The issue was discovered during validation of D16429. Unloading of if_ixlv
followed by immediate removal of VFs with iovctl -D may lead to panic on
NODEBUG kernel.
As well, check if iflib is in detach before enqueueing new admin or iov
tasks, to prevent new tasks from executing while the taskqgroup tasks
are being drained.
Submitted by: Krzysztof Galazka <krzysztof.galazka@intel.com>
Reviewed by: shurd@, erj@
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D17404
Finishes the conversion of the 40Gb Intel Ethernet drivers to iflib(9) for
FreeBSD 12.0, and fixes numerous bugs in both ixl(4) and iavf(4).
This commit also re-adds the VF driver to GENERIC since it now compiles and
functions.
The VF driver name was changed from ixlv(4) to iavf(4) because the VF driver is
now intended to be used with future products, not just with Fortville/Fort Park
VFs.
A man page update that documents these drivers is forthcoming in a separate
commit.
Reviewed by: sbruno@, kbowling@
Tested by: jeffrey.e.pieper@intel.com
Approved by: re (gjb@)
Relnotes: yes
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D16429
Various capabilities were not being handled correctly in the
SIOCSIFCAP handler. Specifically:
IFCAP_RXCSUM and IFCAP_RXCSUM_IPV6 could be set even if not supported
It was impossible to disable IFCAP_RXCSUM and/or IFCAP_RXCSUM_IPV6 via
ifconfig since it does ioctl() per command-line flag rather than combine
them into a single call.
IFCAP_VLAN_HWCSUM could not be modified via the ioctl()
Setting any combination of the three IFCAP_WOL flags would set only
IFCAP_WOL_MCAST | IFCAP_WOL_MAGIC. For example, setting only
IFCAP_WOL_UCAST would result in both IFCAP_WOL_MCAST and IFCAP_WOL_MAGIC
being enabled, but IFCAP_WOL_UCAST would not be enabled.
Because if_vlancap() was called before if_togglecapenable(), vlan flags
were sometimes not applied correctly.
Interfaces were being unnecessarily stopped and restarted for WoL
PR: 231151
Submitted by: Kaho Toshikazu <kaho@elam.kais.kyoto-u.ac.jp>
Reported by: Shirkdog <mshirk@daemon-security.com>
Reviewed by: galladin
Approved by: re (gjb)
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D17158
Remove sysctls:
txq_drain_encapfail - now a duplicate of encap_txd_encap_fail
intr_link - was never incremented
intr_msix - was never incremented
rx_zero_len - was never incremented
The following were not incremented in all code-paths that apply:
m_pullups, mbuf_defrag, rxd_flush, tx_encap, rx_intr_enables, tx_frees,
encap_txd_encap_fail.
Fixes:
Replace the broken collapse_pkthdr() implementation with an MPASS().
fl_refills and fl_refills_large were not incremented when using netmap.
Reviewed by: gallatin
Approved by: re (marius)
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16733
The MP ring may have txq pointers enqueued. Previously, these were
passed to m_free() when IFC_QFLUSH was set. This patch checks for
the value and doesn't call m_free().
Reviewed by: gallatin
Approved by: re (gjb)
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16882
Since r336313, TSO support for LEM-class devices is removed again as it
was before the conversion of {l,}em(4) to iflib(4) in r311849 and as a
result, isc_tx_tso_segments_max is 0 for LEM-class devices now. Thus,
inappropriate watermarks were used for this class.
This is really only a band-aid, though, because so far iflib(9) doesn't
fully take into account that DMA engines can support different maxima
of segments for transfers of TSO and non-TSO packets. For example, the
DESC_RECLAIMABLE macro is based on isc_tx_nsegments while MAX_TX_DESC
used isc_tx_tso_segments_max only. For most in-tree consumers that
doesn't make a difference as the maxima are the same for both kinds of
transfers (that is, apart from the fact that TSO may require up to 2
sentinel descriptors but also not with every MAC supported). However,
isc_tx_nsegments is 8 but isc_tx_tso_segments_max is 85 by default
with ixl(4).
tests for avail > 0, avail can never be 0 within that loop. Thus, move
decrementing avail and budget_left into the loop and before the code which
checks for additional descriptors having become available in case all the
previous ones have been processed but there still is budget left so the
latter code works as expected. [1]
- In iflib_{busdma_load_mbuf_sg,parse_header}(), remove dead stores to m
and n respectively. [2, 3]
- In collapse_pkthdr(), ensure that m_next isn't NULL before dereferencing
it. [4]
- Remove a duplicate assignment of segs in iflib_encap().
Reported by: Coverity
CID: 1356027 [1], 1356047 [2], 1368205 [3], 1356028 [4]
r323954 changed the mp ring behaviour when 64-bit atomics were
available to abdicate the TX ring rather than having one become a
consumer thereby running to completion on TX. The consumer of the mp
ring was then triggered in the tx task rather than blocking the TX call.
While this significantly lowered the number of RX drops in small-packet
forwarding, it also negatively impacts TX performance.
With this change, the default behaviour is reverted, causing one TX ring
to become a consumer during the enqueue call. A new sysctl,
dev.X.Y.iflib.tx_abdicate is added to control this behaviour.
Reviewed by: gallatin
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16302
Use the timer to poll for TX completions when there are
outstanding TX slots. Track when the last driver timer was called
to prevent overcalling it. Also clean up some kring vs NIC ring
usage.
Reviewed by: marius, Johannes Lundberg <johalun0@gmail.com>
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16300
- Ever since the workaround for the silicon bug of TSO4 causing MAC hangs
was committed in r295133, CSUM_TSO always got disabled unconditionally
by em(4) on the first invocation of em_init_locked(). However, even with
that problem fixed, it turned out that for at least e. g. 82579 not all
necessary TSO workarounds are in place, still causing MAC hangs even at
Gigabit speed. Thus, for stable/11, TSO usage was deliberately disabled
in r323292 (r323293 for stable/10) for the EM-class by default, allowing
users to turn it on if it happens to work with their particular EM MAC
in a Gigabit-only environment.
In head, the TSO workaround for speeds other than Gigabit was lost with
the conversion to iflib(9) in r311849 (possibly along with another one
or two TSO workarounds). Yet at the same time, for EM-class MACs TSO4
got enabled by default again, causing device hangs. Therefore, change the
default for this hardware class back to have TSO4 off, allowing users
to turn it on manually if it happens to work in their environment as
we do in stable/{10,11}. An alternative would be to add a whitelist of
EM-class devices where TSO4 actually is reliable with the workarounds in
place, but given that the advantage of TSO at Gigabit speed is rather
limited - especially with the overhead of these workarounds -, that's
really not worth it. [1]
This change includes the addition of an isc_capabilities to struct
if_softc_ctx so iflib(9) can also handle interface capabilities that
shouldn't be enabled by default which is used to handle the default-off
capabilities of e1000 as suggested by shurd@ and moving their handling
from em_setup_interface() to em_if_attach_pre() accordingly.
- Although 82543 support TSO4 in theory, the former lem(4) didn't have
support for TSO4, presumably because TSO4 is even more broken in the
LEM-class of MACs than the later EM ones. Still, TSO4 for LEM-class
devices was enabled as part of the conversion to iflib(9) in r311849,
causing device hangs. So revert back to the pre-r311849 behavior of
not supporting TSO4 for LEM-class at all, which includes not creating
a TSO DMA tag in iflib(9) for devices not having IFCAP_TSO4 set. [2]
- In fact, the FreeBSD TCP stack can handle a TSO size of IP_MAXPACKET
(65535) rather than FREEBSD_TSO_SIZE_MAX (65518). However, the TSO
DMA must have a maxsize of the maximum TSO size plus the size of a
VLAN header for software VLAN tagging. The iflib(9) converted em(4),
thus, first correctly sets scctx->isc_tx_tso_size_max to EM_TSO_SIZE
in em_if_attach_pre(), but later on overrides it with IP_MAXPACKET
in em_setup_interface() (apparently, left-over from pre-iflib(9)
times). So remove the later and correct iflib(9) to correctly cap
the maximum TSO size reported to the stack at IP_MAXPACKET. While at
it, let iflib(9) use if_sethwtsomax*().
This change includes the addition of isc_tso_max{seg,}size DMA engine
constraints for the TSO DMA tag to struct if_shared_ctx and letting
iflib_txsd_alloc() automatically adjust the maxsize of that tag in case
IFCAP_VLAN_MTU is supported as requested by shurd@.
- Move the if_setifheaderlen(9) call for adjusting the maximum Ethernet
header length from {ixgbe,ixl,ixlv,ixv,em}_setup_interface() to iflib(9)
so adjustment is automatically done in case IFCAP_VLAN_MTU is supported.
As a consequence, this adjustment now is also done in case of bnxt(4)
which missed it previously.
- Move the reduction of the maximum TSO segment count reported to the
stack by the number of m_pullup(9) calls (which in the worst case,
can add another mbuf and, thus, the requirement for another DMA
segment each) in the transmit path for performance reasons from
em_setup_interface() to iflib_txsd_alloc() as these pull-ups are now
done in iflib_parse_header() rather than in the no longer existing
em_xmit(). Moreover, this optimization applies to all drivers using
iflib(9) and not just em(4); all in-tree iflib(9) consumers still
have enough room to handle full size TSO packets. Also, reduce the
adjustment to the maximum number of m_pullup(9)'s now performed in
iflib_parse_header().
- Prior to the conversion of em(4)/igb(4)/lem(4) and ixl(4) to iflib(9)
in r311849 and r335338 respectively, these drivers didn't enable
IFCAP_VLAN_HWFILTER by default due to VLAN events not being passed
through by lagg(4). With iflib(9), IFCAP_VLAN_HWFILTER was turned on
by default but also lagg(4) was fixed in that regard in r203548. So
just remove the now redundant and defunct IFCAP_VLAN_HWFILTER handling
in {em,ixl,ixlv}_setup_interface().
- Nuke other redundant IFCAP_* setting in {em,ixl,ixlv}_setup_interface()
which is (more completely) already done in {em,ixl,ixlv}_if_attach_pre()
now.
- Remove some redundant/dead setting of scctx->isc_tx_csum_flags in
em_if_attach_pre().
- Remove some IFCAP_* duplicated either directly or indirectly (e. g.
via IFCAP_HWCSUM) in {EM,IGB,IXL}_CAPS.
- Don't bother to fiddle with IFCAP_HWSTATS in ixgbe(4)/ixgbev(4) as
iflib(9) adds that capability unconditionally.
- Remove some unused macros from em(4).
- Bump __FreeBSD_version as some of the above changes require the modules
of drivers using iflib(9) to be recompiled.
Okayed by: sbruno@ at 201806 DevSummit Transport Working Group [1]
Reviewed by: sbruno (earlier version), erj
PR: 219428 (part of; comment #10) [1], 220997 (part of; comment #3) [2]
Differential Revision: https://reviews.freebsd.org/D15720
- In iflib_msix_init(), VMMs with broken MSI-X activation are trying
to be worked around by manually enabling PCIM_MSIXCTRL_MSIX_ENABLE
before calling pci_alloc_msix(9). Apart from constituting a layering
violation, this has the problem of leaving PCIM_MSIXCTRL_MSIX_ENABLE
enabled when falling back to MSI or INTx when e. g. MSI-X is black-
listed and initially also when disabled via hw.pci.enable_msix. The
later in turn was incorrectly worked around in r325166.
Since r310806, pci(4) itself has code to deal with broken MSI-X
handling of VMMs, so all of these workarounds in iflib(9) can go,
fixing non-working interrupts when falling back to MSI/INTx. In
any case, possibly further adjustments to broken MSI-X activation
of VMMs like enabling r310806 by default in VM environments need to
be placed into pci(4), not iflib(9). [1]
- Also remove the pci_enable_busmaster(9) call from iflib_msix_init(),
which is already more properly invoked from iflib_device_attach().
- When falling back to MSI/INTx, release the MSI-X BAR resource again.
- When falling back to INTx, ensure scctx->isc_vectors is set to 1 and
not to something higher from a device with more than one MSI message
supported.
- Make the nearby ring_state(s) stuff (static) const.
Discussed with: jhb at BSDCan 2018 [1]
Reviewed by: imp, jhb
Differential Revision: https://reviews.freebsd.org/D15729
This caused issues with PASTE. Just remove the reschedule since the DELAY()
should be enough for use cases such as pkt-gen which were failing before the
change.
Reported by: Michio Honda
Sponsored by: Limelight Networks
ixl(4) (when it switches over to using iflib) devices need the TCP header
length in order to do TCP checksum offload.
Reviewed by: gallatin@, shurd@
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D15558
The *name parameter passed to iflib_irq_alloc_generic and
iflib_softirq_alloc_generic is never modified. Many places in code pass
string literals and thus should not be modified.
Mark the *name parameter as a const char * instead, so that we enforce
that the name is not modified before passing to bus_describe_intr()
Submitted by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed by: kmacy
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D15343
ixl(4)'s nvmupdate utility expects the nvmupdate process to run
while the interface is down; these nvm update commands use the
admin queue, so the admin queue needs to be able to generate
interrupts and be processed while the interface is down.
So add a flag that ixl(4) sets that lets the entire admin task
run even when the interface is marked down/IFF_DRV_RUNNING isn't set.
With this change, nvmupdate should function like it did pre-iflib.
Reviewed by: gallatin@, sbruno@
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D15575
When poll() is called via netmap, txsync is initially called,
and if there are no available buffers to reclaim, it waits for the driver
to notify of new buffers. Since the TX IRQ is generally not used in iflib
drivers, this ends up causing a timeout.
Work around this by having the reclaim DELAY(1) if it's initially unable
to reclaim anything, then schedule the tx task, which will spin by
continuously rescheduling itself until some buffers are reclaimed. In
general, the delay is enough to allow some buffers to be reclaimed, so
spinning is minimized.
Reported by: Johannes Lundberg <johalun0@gmail.com>
Reviewed by: sbruno
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D15455
Part 3 of many ...
The VPC framework relies heavily on cloning pseudo interfaces
(vmnics, vpc switch, vcpswitch port, hostif, vxlan if, etc).
This pulls in that piece. Some ancillary changes get pulled
in as a side effect.
Reviewed by: shurd@
Approved by: sbruno@
Sponsored by: Joyent, Inc.
Differential Revision: https://reviews.freebsd.org/D15347
Print a message when iflib_tx_structures_setup fails, like we do for
iflib_rx_structures_setup.
Now that we always print a message from within
iflib_qset_structures_setup when it fails, stop printing one in
iflib_device_register() at the call site.
Submitted by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed by: gallatin
MFC after: 3 days
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D15300
The canonical check for whether or not a ring is drainable is
TXQ_AVAIL() > MAX_TX_DESC() + 2. Use this same construct here,
in order to avoid a potential off-by-one error where we might otherwise
fail to request an interrupt.
Reviewed by: mmacy
Sponsored by: Netflix
em(4) and igb(4) were tested by me, and ixgbe(4) and bnxt(4) were
tested by sbruno.
Reviewed by: mmacy, shurd
MFC after: 1 month
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D15262
In r301567, code was added to cleanup to prevent memory leaks for the
Tx and Rx ring structs. This code carefully tracked txq and rxq, and
made sure to free them properly during cleanup.
Because we assigned the txq and rxq pointers into the ctx->ifc_txqs and
ctx->ifc_rxqs, we carefully reset these pointers to NULL, so that
cleanup code would not accidentally free the memory twice.
This was changed by r304021 ("Update iflib to support more NIC designs"),
which removed this resetting of the pointers to NULL, because it re-used
the txq and rxq pointers as an index into the queue set array.
Unfortunately, the cleanup code was left alone. Thus, if we fail to
allocate DMA or fail to configure the queues using the drivers ifdi
methods, we will attempt to free txq and rxq. These variables would now
incorrectly point to the wrong location, resulting in a page fault.
There are a number of methods to correct this, but ultimately the root
cause was that we reuse the txq and rxq pointers for two different
purposes.
Instead, when allocating, store the returned pointer directly into
ctx->ifc_txqs and ctx->ifc_rxqs. Then, assign this to txq and rxq as
index pointers before starting the loop to allocate each queue.
Drop the cleanup code for txq and rxq, and only use ctx->ifc_txqs and
ctx->ifc_rxqs.
Thus, we no longer need to free txq or rxq under any error flow, and
intsead rely solely on the pointers stored in ctx->ifc_txqs and
ctx->ifc_rxqs. This prevents the invalid free(), and ensures that we
still properly cleanup after ourselves as before when failing to
allocate.
Submitted by: Jacob Keller
Reviewed by: gallatin, sbruno
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D15285
This pointer was no longer written to as of r315217. Since nothing writes
to the variable, remove it.
Submitted by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed by: gallatin, kmacy, sbruno
Differential Revision: https://reviews.freebsd.org/D15284
Since the move to SMP NIC driver locking has had to go through serious
contortions using mtx around long running hardware operations. This moves
iflib past that.
Individual drivers may now sleep when appropriate.
Submitted by: Matthew Macy <mmacy@mattmacy.io>
Reviewed by: shurd
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D14983
1) Don't give up if m_collapse() fails. Rather than giving up, try
m_defrag() immediately.
2) Fix a leak where, if the NIC driver rejected the defrag'ed chain
as having too many segments, we would fail to free the chain.
Reviewed by: Matthew Macy <mmacy@mattmacy.io> (this version of patch)
Submitted by: Matthew Macy <mmacy@mattmacy.io> (early version of leak fix)
Previously, if there are no threads, all queues which targeted
cores that share an L2 cache were bound to a single core. The intent is
to distribute them across these cores.
Reported by: olivier
Reviewed by: sbruno
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D15120
Add one extra lock initialization to iflib_register() that was missed
in the git<->phab conversion.
Split out flag manipulation from general context manipulation in iflib
To avoid blocking on the context lock in the swi thread and risk potential
deadlocks, this change protects lighter weight updates that only need to
be consistent with each other with their own lock.
Submitted by: Matthew Macy <mmacy@mattmacy.io>
Reviewed by: shurd
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D14967
Changelist:
- Turn tx_rings and rx_rings arrays into arrays of pointers to kring
structs. This patch includes fixes for ixv, ixl, ix, re, cxgbe, iflib,
vtnet and ptnet drivers to cope with the change.
- Generalize the nm_config() callback to accept a struct containing many
parameters.
- Introduce NKR_FAKERING to support buffers sharing (used for netmap
pipes)
- Improved API for external VALE modules.
- Various bug fixes and improvements to the netmap memory allocator,
including support for externally (userspace) allocated memory.
- Refactoring of netmap pipes: now linked rings share the same netmap
buffers, with a separate set of kring pointers (rhead, rcur, rtail).
Buffer swapping does not need to happen anymore.
- Large refactoring of the control API towards an extensible solution;
the goal is to allow the addition of more commands and extension of
existing ones (with new options) without the need of hacks or the
risk of running out of configuration space.
A new NIOCCTRL ioctl has been added to handle all the requests of the
new control API, which cover all the functionalities so far supported.
The netmap API bumps from 11 to 12 with this patch. Full backward
compatibility is provided for the old control command (NIOCREGIF), by
means of a new netmap_legacy module. Many parts of the old netmap.h
header has now been moved to netmap_legacy.h (included by netmap.h).
Approved by: hrs (mentor)
Also, since ifc_nhwrxqs is only used in one place, remove it from the struct.
This was preventing iflib_dma_free() from being called via
iflib_device_detach().
Submitted by: Matthew Macy <mmacy@mattmacy.io>
Reviewed by: shurd
Sponsored by: Limelight Networks
