Commit Graph

164 Commits

Author SHA1 Message Date
Hans Petter Selasky
f0188618f2 Fix multiple incorrect SYSCTL arguments in the kernel:
- Wrong integer type was specified.

- Wrong or missing "access" specifier. The "access" specifier
sometimes included the SYSCTL type, which it should not, except for
procedural SYSCTL nodes.

- Logical OR where binary OR was expected.

- Properly assert the "access" argument passed to all SYSCTL macros,
using the CTASSERT macro. This applies to both static- and dynamically
created SYSCTLs.

- Properly assert the the data type for both static and dynamic
SYSCTLs. In the case of static SYSCTLs we only assert that the data
pointed to by the SYSCTL data pointer has the correct size, hence
there is no easy way to assert types in the C language outside a
C-function.

- Rewrote some code which doesn't pass a constant "access" specifier
when creating dynamic SYSCTL nodes, which is now a requirement.

- Updated "EXAMPLES" section in SYSCTL manual page.

MFC after:	3 days
Sponsored by:	Mellanox Technologies
2014-10-21 07:31:21 +00:00
Adrian Chadd
bba61d1a89 Set the DROP_EN bit before the RX queue is brought up and active.
He noticed issues setting this bit in SRRCTL after the queue was up,
so doing it from the sysctl handler isn't enough and may not actually
work correctly.

This commit doesn't remove the sysctl path or try to change its
behaviour.  I'll talk with others about how to finish fixing that
before I tackle that.

PR:		kern/194311
Submitted by:	luigi
MFC after:	3 days
Sponsored by:	Norse Corp, Inc
2014-10-15 01:22:56 +00:00
Gleb Smirnoff
058a38660e Convert to if_get_counter(). 2014-09-28 07:29:45 +00:00
Gleb Smirnoff
5fe12776aa Mechanically switch ixv(4) to if_inc_counter(). 2014-09-28 07:19:32 +00:00
Adrian Chadd
e45d876dd7 The error bits are not valid with EOP=0; so intermediary fragments should
not be discarded.

Submitted by:	Marc De La Gueronniere <mdelagueronniere@verisign.com>
MFC after:	1 week
Sponsored by:	Verisign, Inc.
2014-09-15 20:54:12 +00:00
Adrian Chadd
5894690d0d Fix a double-free of mbufs in rx_ixgbe_discard().
fmp->buf at the free point is already part of the chain being freed,
so double-freeing is counter-productive.

Submitted by:	Marc De La Gueronniere <mdelagueronniere@verisign.com>
MFC after:	1 week
Sponsored by:	Verisign, Inc.
2014-09-15 20:50:26 +00:00
Christian Brueffer
380064c8dc Use the right constants in comparisons. This is currently a nop, as
MIN_RXD == MIN_TXD and MAX_RXD == MAX_TXD.

Reviewed by:	Eric Joyner @ Intel
MFC after:	1 week
2014-09-08 19:24:25 +00:00
Gleb Smirnoff
1bffa9511f Use define from if_var.h to access a field inside struct if_data,
that resides in struct ifnet.

Sponsored by:	Nginx, Inc.
2014-08-30 19:55:54 +00:00
Alexander V. Chernikov
ea463f2dc0 * Add SIOCGI2C driver ioctl used to retrieve i2c info.
* Convert ixgbe to use this ioctl
* Convert ifconfig to use generic i2c handler for  "ix" interfaces.

Approved by:	Eric Joyner (ixgbe part)
MFC after:	2 weeks
Sponsored by:	Yandex LLC
2014-08-29 18:02:58 +00:00
Luigi Rizzo
4bf50f18eb Update to the current version of netmap.
Mostly bugfixes or features developed in the past 6 months,
so this is a 10.1 candidate.

Basically no user API changes (some bugfixes in sys/net/netmap_user.h).

In detail:

1. netmap support for virtio-net, including in netmap mode.
  Under bhyve and with a netmap backend [2] we reach over 1Mpps
  with standard APIs (e.g. libpcap), and 5-8 Mpps in netmap mode.

2. (kernel) add support for multiple memory allocators, so we can
  better partition physical and virtual interfaces giving access
  to separate users. The most visible effect is one additional
  argument to the various kernel functions to compute buffer
  addresses. All netmap-supported drivers are affected, but changes
  are mechanical and trivial

3. (kernel) simplify the prototype for *txsync() and *rxsync()
  driver methods. All netmap drivers affected, changes mostly mechanical.

4. add support for netmap-monitor ports. Think of it as a mirroring
  port on a physical switch: a netmap monitor port replicates traffic
  present on the main port. Restrictions apply. Drive carefully.

5. if_lem.c: support for various paravirtualization features,
  experimental and disabled by default.
  Most of these are described in our ANCS'13 paper [1].
  Paravirtualized support in netmap mode is new, and beats the
  numbers in the paper by a large factor (under qemu-kvm,
  we measured gues-host throughput up to 10-12 Mpps).

A lot of refactoring and additional documentation in the files
in sys/dev/netmap, but apart from #2 and #3 above, almost nothing
of this stuff is visible to other kernel parts.

Example programs in tools/tools/netmap have been updated with bugfixes
and to support more of the existing features.

This is meant to go into 10.1 so we plan an MFC before the Aug.22 deadline.

A lot of this code has been contributed by my colleagues at UNIPI,
including Giuseppe Lettieri, Vincenzo Maffione, Stefano Garzarella.

MFC after:	3 days.
2014-08-16 15:00:01 +00:00
Steven Hartland
d7b5bae512 Renamed hw.ixgbe.unsupported_sfp -> hw.ix.unsupported_sfp
This now matches all other ixgbe sysctl / tunables.

Sponsored by:	Multiplay
2014-08-14 13:25:05 +00:00
Adrian Chadd
ce44e5f776 Add the UDP hash -> RSS mbuf hash type for the ixgbe(4) driver. 2014-07-20 08:43:53 +00:00
Adrian Chadd
e3af537e75 Teach ixgbe(4) about rss_gethashconfig().
If RSS is enabled, ixgbe(4) will query the RSS API for the types of hashes
which should be used.  It'll then only enable hashes that are exposed via
the RSS layer.

This way it won't try to do things like enable UDP hashing if RSS explicitly
states that it isn't supported in lookups.

Tested:

* 82599EB ixgbe(4) NIC
2014-07-20 07:45:48 +00:00
Adrian Chadd
e965b0dcd1 Disable the ixgbe(4) UDP 4-tuple hashing for the time being.
A mix of fragmented and non-fragmented UDP in a single stream will end up
being hashed differently, resulting in out-of-order behaviour in the receive
path.

This was done in the linux e1000 driver in 2011.

Discussed with:	jfv
2014-07-20 07:43:41 +00:00
Adrian Chadd
c64a6bc62d Correctly program the RSS redirection table entries.
Without this, the RSS bucket assignments aren't correct - they're
DCBA instead of ABCD in each DWORD.

Tested:	82599EB ixgbe(4), TCP and UDP RSS
2014-07-20 04:11:18 +00:00
Hiren Panchasara
2814ea66e3 Fix a typo.
PR:		191898
Submitted by:	vsjcfm@gmail.com
2014-07-17 06:21:58 +00:00
Adrian Chadd
8c0d2adf3f Initialise these variables so gcc doesn't complain.
Submitted by:	luigi
2014-06-30 23:34:36 +00:00
Adrian Chadd
7063e348ab Add initial RSS awareness to the ixgbe(4) driver.
The ixgbe(4) hardware is capable of RSS hashing RX packets and doing RSS
queue selection for up to 8 queues.

However, even if multi-queue is enabled for ixgbe(4), the RX path doesn't use
the RSS flowid from the received descriptor.  It just uses the MSIX queue id.

This patch does a handful of things if RSS is enabled:

* Instead of using a random key at boot, fetch the RSS key from the RSS code
  and program that in to the RSS redirection table.

  That whole chunk of code should be double checked for endian correctness.

* Use the RSS queue mapping to CPU ID to figure out where to thread pin
  the RX swi thread and the taskqueue threads for each queue.

* The software queue is now really an "RSS bucket".

* When programming the RSS indirection table, use the RSS code to
  figure out which RSS bucket each slot in the indirection table maps
  to.

* When transmitting, use the flowid RSS mapping if the mbuf has
  an RSS aware hash.  The existing method wasn't guaranteed to align
  correctly with the destination RSS bucket (and thus CPU ID.)

This code warns if the number of RSS buckets isn't the same as the
automatically configured number of hardware queues.  The administrator
will have to tweak one of them for better performance.

There's currently no way to re-balance the RSS indirection table after
startup.  I'll worry about that later.

Additionally, it may be worthwhile to always use the full 32 bit flowid if
multi-queue is enabled.  It'll make things like lagg(4) behave better with
respect to traffic distribution.
2014-06-30 04:38:29 +00:00
Hans Petter Selasky
af3b2549c4 Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
Glen Barber
37a107a407 Revert r267961, r267973:
These changes prevent sysctl(8) from returning proper output,
such as:

 1) no output from sysctl(8)
 2) erroneously returning ENOMEM with tools like truss(1)
    or uname(1)
 truss: can not get etype: Cannot allocate memory
2014-06-27 22:05:21 +00:00
Hans Petter Selasky
3da1cf1e88 Extend the meaning of the CTLFLAG_TUN flag to automatically check if
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after:	2 weeks
Sponsored by:	Mellanox Technologies
2014-06-27 16:33:43 +00:00
John Baldwin
46e89834dc - Don't compare bus_dma map pointers for static DMA allocations against
NULL to determine if bus_dmamap_unload() or bus_dmamem_free() should be
  called.  Instead, check the associated bus and virtual addresses.
- Don't clear static DMA maps to NULL.

Reviewed by:	jfv
2014-06-12 11:15:19 +00:00
Luigi Rizzo
c7156fe92f make sure if_transmit returns 0 if the mbuf is enqueued.
ixgbe/ixv.c still needs a similar fix but it takes a little
more restructuring of the code.

MFC after:	3 days
2014-06-06 20:49:56 +00:00
Gleb Smirnoff
b245f96c44 Since 32-bit if_baudrate isn't enough to describe a baud rate of a 10 Gbit
interface, in the r241616 a crutch was provided. It didn't work well, and
finally we decided that it is time to break ABI and simply make if_baudrate
a 64-bit value. Meanwhile, the entire struct if_data was reviewed.

o Remove the if_baudrate_pf crutch.

o Make all fields of struct if_data fixed machine independent size. The
  notion of data (packet counters, etc) are by no means MD. And it is a
  bug that on amd64 we've got a 64-bit counters, while on i386 32-bit,
  which at modern speeds overflow within a second.

  This also removes quite a lot of COMPAT_FREEBSD32 code.

o Give 16 bit for the ifi_datalen field. This field was provided to
  make future changes to if_data less ABI breaking. Unfortunately the
  8 bit size of it had effectively limited sizeof if_data to 256 bytes.

o Give 32 bits to ifi_mtu and ifi_metric.
o Give 64 bits to the rest of fields, since they are counters.

__FreeBSD_version bumped.

Discussed with:	emax
Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2014-03-13 03:42:24 +00:00
Luigi Rizzo
17885a7bfd It is 2014 and we have a new version of netmap.
Most relevant features:

- netmap emulation on any NIC, even those without native netmap support.

  On the ixgbe we have measured about 4Mpps/core/queue in this mode,
  which is still a lot more than with sockets/bpf.

- seamless interconnection of VALE switch, NICs and host stack.

  If you disable accelerations on your NIC (say em0)

        ifconfig em0 -txcsum -txcsum

  you can use the VALE switch to connect the NIC and the host stack:

        vale-ctl -h valeXX:em0

  allowing sharing the NIC with other netmap clients.

- THE USER API HAS SLIGHTLY CHANGED (head/cur/tail pointers
  instead of pointers/count as before). This was unavoidable to support,
  in the future, multiple threads operating on the same rings.
  Netmap clients require very small source code changes to compile again.
      On the plus side, the new API should be easier to understand
  and the internals are a lot simpler.

The manual page has been updated extensively to reflect the current
features and give some examples.

This is the result of work of several people including Giuseppe Lettieri,
Vincenzo Maffione, Michio Honda and myself, and has been financially
supported by EU projects CHANGE and OPENLAB, from NetApp University
Research Fund, NEC, and of course the Universita` di Pisa.
2014-01-06 12:53:15 +00:00
Gleb Smirnoff
f56831a217 Fix build broken in r259644.
Submitted by:	tuexen
Pointy hat to:	glebius
2013-12-20 13:18:50 +00:00
Gleb Smirnoff
46bf53de69 ixgbe(4) takes packet counters from hardware in ixgbe_update_stats_counters(),
so we don't need to do a per packet increment, which trashes cache line.

Submitted by:	oleg
2013-12-20 10:57:47 +00:00
Oleg Bulyzhin
ba36d317f6 - Fix link loss on vlan reconfiguration.
- Fix issues with 'vlanhwfilter'.

MFC after:	1 week
Silence from:	jfv 5 weeks
2013-11-05 09:46:01 +00:00
Luigi Rizzo
ce3ee1e7c4 update to the latest netmap snapshot.
This includes the following:
- use separate memory regions for VALE ports
- locking fixes
- some simplifications in the NIC-specific routines
- performance improvements for the VALE switch
- some new features in the pkt-gen test program
- documentation updates

There are small API changes that require programs to be recompiled
(NETMAP_API has been bumped so you will detect old binaries at runtime).

In particular:
- struct netmap_slot now is 16 bytes to support an extra pointer,
  which may save one data copy when using VALE ports or VMs;
- the struct netmap_if has two extra fields;

MFC after:	3 days
2013-11-01 21:21:14 +00:00
Gleb Smirnoff
76039bc84f The r48589 promised to remove implicit inclusion of if_var.h soon. Prepare
to this event, adding if_var.h to files that do need it. Also, include
all includes that now are included due to implicit pollution via if_var.h

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2013-10-26 17:58:36 +00:00
Gleb Smirnoff
4cdc1f5421 There are some high performance NICs that count statistics in hardware,
and there are ifnets, that do that via counter(9). Provide a flag that
would skip cache line trashing '+=' operation in ether_input().

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
Reviewed by:	melifaro, adrian
Approved by:	re (marius)
2013-10-09 19:04:40 +00:00
Hiren Panchasara
5b9d734b08 Expose system level ixgbe sysctls.
Device level sysctls are already exposed as dev.ix.<device>

Fixing the case where number of queues for igb is auto-tuned and
hw.igb.num_queues does not return current/updated value.

Reviewed by:	jfv
Approved by:	re (delphij)
MFC after:	2 weeks
2013-10-05 19:17:56 +00:00
Andre Oppermann
1b4381afbb Restructure the mbuf pkthdr to make it fit for upcoming capabilities and
features.  The changes in particular are:

o Remove rarely used "header" pointer and replace it with a 64bit protocol/
  layer specific union PH_loc for local use.  Protocols can flexibly overlay
  their own 8 to 64 bit fields to store information while the packet is
  worked on.

o Mechanically convert IP reassembly, IGMP/MLD and ATM to use pkthdr.PH_loc
  instead of pkthdr.header.

o Extend csum_flags to 64bits to allow for additional future offload
  information to be carried (e.g. iSCSI, IPsec offload, and others).

o Move the RSS hash type enumerator from abusing m_flags to its own 8bit
  rsstype field.  Adjust accessor macros.

o Add cosqos field to store Class of Service / Quality of Service information
  with the packet.  It is not yet supported in any drivers but allows us to
  get on par with Cisco/Juniper in routing applications (plus MPLS QoS) with
  a modernized ALTQ.

o Add four 8 bit fields l[2-5]hlen to store the relative header offsets
  from the start of the packet.  This is important for various offload
  capabilities and to relieve the drivers from having to parse the packet
  and protocol headers to find out location of checksums and other
  information.  Header parsing in drivers is a lot of copy-paste and
  unhandled corner cases which we want to avoid.

o Add another flexible 64bit union to map various additional persistent
  packet information, like ether_vtag, tso_segsz and csum fields.
  Depending on the csum_flags settings some fields may have different usage
  making it very flexible and adaptable to future capabilities.

o Restructure the CSUM flags to better signify their outbound (down the
  stack) and inbound (up the stack) use.  The CSUM flags used to be a bit
  chaotic and rather poorly documented leading to incorrect use in many
  places.  Bring clarity into their use through better naming.
  Compatibility mappings are provided to preserve the API.  The drivers
  can be corrected one by one and MFC'd without issue.

o The size of pkthdr stays the same at 48/56bytes (32/64bit architectures).

Sponsored by:	The FreeBSD Foundation
2013-08-24 19:51:18 +00:00
Scott Long
c68534f1d5 Update PCI drivers to no longer look at the MEMIO-enabled bit in the PCI
command register.  The lazy BAR allocation code in FreeBSD sometimes
disables this bit when it detects a range conflict, and will re-enable
it on demand when a driver allocates the BAR.  Thus, the bit is no longer
a reliable indication of capability, and should not be checked.  This
results in the elimination of a lot of code from drivers, and also gives
the opportunity to simplify a lot of drivers to use a helper API to set
the busmaster enable bit.

This changes fixes some recent reports of disk controllers and their
associated drives/enclosures disappearing during boot.

Submitted by:	jhb
Reviewed by:	jfv, marius, achadd, achim
MFC after:	1 day
2013-08-12 23:30:01 +00:00
Jack F Vogel
4dc63104ae Improve the MSIX setup code in the drivers, thanks to Marius for
the changes. Make sure that pci_alloc_msix() does give us the vectors
we need and fall back to MSI when it doesn't, also release any that
were allocated when insufficient.

MFC after: 3 days
2013-08-12 22:54:38 +00:00
Jack F Vogel
d0913b7f25 Make the various driver MSIX setup routines fallback to MSI more
gracefully. This change was suggested by Marius Strobl, thank you.

PR: kern/181016
MFC after: ASAP
2013-08-06 21:01:38 +00:00
Jack F Vogel
7301d64aba Correct a fat-finger in the last delta.
MFC after: ASAP
2013-08-05 16:16:50 +00:00
Jack F Vogel
cbe75ae8f5 A number of important fixes:
- mbuf reused after an RX_COPY optimized operation can sometimes have
    a bogus cached address, resulting in TCP hangs. Add critical save points
    to the cached address. Thanks to Michael and the team at Verisign for
    finding this problem.
  - A couple more spots where the rxbuf->flags member should be cleared just
    to be sure no incorrect RX_COPY state is left around. Thanks to Adrian
    for tracking these down.
  - Remove the rearm_queues function from the driver, this was found to be
    responsible for some out-of-order packets by Verisign, and was always a
    bandaid, with the other fixes in this delta the bandaid can finally be
    removed.
  - In the other/link interrupt handler the entire state of the EICS register
    was being writen back into EICR (which clears causes and thus re-enables
    those interrupts), this was wrong, so now mask off the queue portion of
    the register value, so we only clear the other/link interrupt we intend.
    Marc from Verisign found this.
  - Make the SFP+ unsupported option tuneable now, by customer request.
  - Finally, just a couple of minor DEBUG string fixes.

I want to call out and thank all the participants in the 10G community/Intel
calls for helping track down these problems and make the driver better for
everyone!

MFC after:	3 days, these are critical fixes for 9.2!
2013-08-01 20:10:16 +00:00
Jack F Vogel
bae4b87e8a Opps, need to change the VF code as well.
MFC after:	ASAP
2013-07-12 21:21:15 +00:00
Jack F Vogel
ee738eea01 Remove the conditional define around the option headers,
when building the driver as a module the result of the present
system results in INET and INET6 being undefined, and will cause
the panic in ixgbe_tso_setup(). The Makefile in the module directory
now renders the conditional in the source unnecessary and wrong.

MFC after: ASAP - the panic as a module must not get into 9.2
2013-07-12 21:14:42 +00:00
Jack F Vogel
3f80cc03fd Fix my last commit, flags rather than flag... duh.
MFC after: 2 days
2013-07-11 03:44:06 +00:00
Jack F Vogel
804d70535a Fix to a panic found internally, bad pointer during rxeof
processing. Thanks for John Baldwin for catching this. Not
clearing the flag member of the rxbuf could result in a NULL
mbuf pointer being used.

MFC after:	2 days (this needs to get into 9.2!)
2013-07-10 23:14:24 +00:00
Jack F Vogel
fd75b91d13 Add quad port probe support, this gives the admin proper information about the slot
(which should be a PCIE Gen 3 slot for this adapter) by looking back thru the PCI
parent devices to the slot device.

The fix above also corrects the bandwidth display to GT/s rather than the
incorrect Gb/s

Next, allow the use of ALTQ if you select the compile option IXGBE_LEGACY_TX.

Allow the use of 'unsupported' optic modules by a compile option as well.

Add a phy reset capability into the stop code, this is so a static configured
driver will still behave properly when taken down (not being able to unload it).

This revision synchronizes the shared code with Intel internal current code,
and note that it now includes DCB supporting code, this was necessitated by
some internal changes with the code, but it also will provide the opportunity
to develop this feature in the core driver down the road.

I have edited the README to get rid of some of the worse anachronisms in it
as well, its by no means as robust as I might wish at this point however.

Oh, I also have included some conditional stuff in the code so it will be
compatible in both the 9.X and 10 environments.

Performance has been a focus in recent changes and I believe this revision
driver will perform very well in most workloads.

MFC after: 2 weeks
2013-06-18 21:28:19 +00:00
Luigi Rizzo
d61ba75247 use netmap_rx_irq() / netmap_tx_irq() to handle interrupts in
netmap mode, removing the logic from individual drivers.

(note: if_lem.c not updated yet due to some other pending modifications)
2013-04-30 16:18:29 +00:00
Jack F Vogel
7bdac10465 Two small fixes:
Set promiscuous code was unconditionally turning off multicast when
  turning off promiscuous mode, this should only be done when there are
  less than MAX groups. Thanks to Mike Karels for this correction.

  Second, the overtmp interrupt setup/detection was wrong, correcting it.

MFC after:	one week
2013-03-29 18:03:00 +00:00
Jack F Vogel
facc592d88 Fix a small, but important bug, a task drain was mistakenly
being compiled only when setting LEGACY_TX, this means you would
not get the drain when needed on detach!!

Thanks to Bryan Venteicher (bryanv@freebsd.org) for catching this
little gremlin!! :)
2013-03-04 23:15:07 +00:00
Jack F Vogel
0ecc2ff0e8 First, sync to internal shared code, and then
Fixes:
	- flow control - don't override user value on re-init
	- fix to make 1G optics work correctly
	- change to interrupt enabling - some bits were incorrect
	  for certain hardware.
	- certain stats fixes, remove a duplicate increment of
	  ierror, thanks to Scott Long for pointing these out.
	- shared code link interface changed, requiring some
	  core code changes to accomodate this.
	- add an m_adj() to ETHER_ALIGN on the recieve side, this
	  was requested by Mike Karels, thanks Mike.
	- Multicast code corrections also thanks to Mike Karels.
2013-03-04 23:07:40 +00:00
Dag-Erling Smørgrav
cdc1296734 revert 247035 2013-02-20 21:16:50 +00:00
Dag-Erling Smørgrav
c9263bd288 Reduce excessive nesting. 2013-02-20 12:59:21 +00:00
Randall Stewart
ded5ea6a25 This fixes a out-of-order problem with several
of the newer drivers. The basic problem was
that the driver was pulling the mbuf off the
drbr ring and then when sending with xmit(), encounting
a full transmit ring. Thus the lower layer
xmit() function would return an error, and the
drivers would then append the data back on to the ring.
For TCP this is a horrible scenario sure to bring
on a fast-retransmit.

The fix is to use drbr_peek() to pull the data pointer
but not remove it from the ring. If it fails then
we either call the new drbr_putback or drbr_advance
method. Advance moves it forward (we do this sometimes
when the xmit() function frees the mbuf). When
we succeed we always call advance. The
putback will always copy the mbuf back to the top
of the ring. Note that the putback *cannot* be used
with a drbr_dequeue() only with drbr_peek(). We most
of the time, in putback, would not need to copy it
back since most likey the mbuf is still the same, but
sometimes xmit() functions will change the mbuf via
a pullup or other call. So the optimial case for
the single consumer is to always copy it back. If
we ever do a multiple_consumer (for lagg?) we
will  need a test and atomic in the put back possibly
a seperate putback_mc() in the ring buf.

Reviewed by:	jhb@freebsd.org, jlv@freebsd.org
2013-02-07 15:20:54 +00:00