Commit Graph

119968 Commits

Author SHA1 Message Date
Ingo Molnar
a098397d56 atlx: fix warning in drivers/net/atlx/atl2.c
fix this warning:

  drivers/net/atlx/atl2.c: In function ‘atl2_request_irq’:
  drivers/net/atlx/atl2.c:644: warning: unused variable ‘err’

'err' is unused in the !CONFIG_PCI_MSI case.

Instead of further increasing the #ifdeffery in this function,
restructure the code a bit and get rid of the #ifdef. This
relies on the fact that pci_enable_msi() will always fail in
the !CONFIG_PCI_MSI case.

There should be no change in driver behavior.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 17:00:05 -08:00
Ingo Molnar
45555c0ed4 bluetooth: fix warning in net/bluetooth/rfcomm/sock.c
fix this warning:

  net/bluetooth/rfcomm/sock.c: In function ‘rfcomm_sock_ioctl’:
  net/bluetooth/rfcomm/sock.c:795: warning: unused variable ‘sk’

perhaps BT_DEBUG() should be improved to do printf format checking
instead of the #ifdef, but that looks quite intrusive: each bluetooth
.c file undefines the macro.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:59:21 -08:00
Ingo Molnar
ff0db0490a sunrpc: fix warning in net/sunrpc/xprtrdma/verbs.c
fix this warning:

  net/sunrpc/xprtrdma/verbs.c: In function ‘rpcrdma_conn_upcall’:
  net/sunrpc/xprtrdma/verbs.c:279: warning: unused variable ‘addr’

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:58:42 -08:00
Ingo Molnar
e14bec2e2b ax25: fix warning in net/ax25/sysctl_net_ax25.c
fix this warning:

  net/ax25/sysctl_net_ax25.c:27: warning: ‘min_ds_timeout’ defined but not used
  net/ax25/sysctl_net_ax25.c:27: warning: ‘max_ds_timeout’ defined but not used

These are only used in the CONFIG_AX25_DAMA_SLAVE case.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:58:19 -08:00
Ingo Molnar
e6a176228a mlx4: fix warning in drivers/net/mlx4/mcg.c
fix warning:

  drivers/net/mlx4/mcg.c: In function ‘mlx4_multicast_attach’:
  drivers/net/mlx4/mcg.c:217: warning: integer overflow in expression

there was no real danger of overflow here though.

md5:
   db8eb55620f886c03854a2abb2ce6c3f  mcg.o.before.asm
   db8eb55620f886c03854a2abb2ce6c3f  mcg.o.after.asm

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:57:59 -08:00
Ingo Molnar
3ed7cc0f8b dccp: fix warning in net/dccp/options.c
this warning:

  net/dccp/options.c: In function ‘dccp_parse_options’:
  net/dccp/options.c:67: warning: ‘value’ may be used uninitialized in this function

is a bogus GCC warning. The compiler does not recognize the relation
between "value" and "mandatory" variables: the code flow can ever reach
the "out_invalid_option:" label if 'mandatory' is set to 1, and when
'mandatory' is non-zero, we'll always have 'value' initialized.

Help out the compiler by annotating the variable.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:57:30 -08:00
Ingo Molnar
b71e839f9a cassini: fix warning in drivers/net/cassini.c
this warning:

  drivers/net/cassini.c: In function ‘cas_rx_ringN’:
  drivers/net/cassini.c:2350: warning: ‘skb’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between cas_rx_process_pkt() and 'skb'.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:57:05 -08:00
Ingo Molnar
b58515be97 mlx4: fix error path in drivers/net/mlx4/en_rx.c
this warning:

  drivers/net/mlx4/en_rx.c: In function ‘mlx4_en_activate_rx_rings’:
  drivers/net/mlx4/en_rx.c:412: warning: ‘err’ may be used uninitialized in this function

Triggers because 'err' is uninitialized in the following input
conditions: priv->rx_ring_num is zero and mlx4_en_fill_rx_buffers()
fails.

But even if ->rx_ring_num is nonzero, 'err' will be zero if
mlx4_en_fill_rx_buffers() fails and mlx4_en_activate_rx_rings() returns
success - incorrectly.

So it's best to keep the error code uptodate on mlx4_en_fill_rx_buffers()
calls as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:53:32 -08:00
Ingo Molnar
4174439ef5 z85230: fix warning in drivers/net/wan/z85230.c
this warning:

  drivers/net/wan/z85230.c: In function ‘z8530_interrupt’:
  drivers/net/wan/z85230.c:713: warning: ‘intr’ may be used uninitialized in this function

is clearly bogus - annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:53:08 -08:00
Ingo Molnar
ef0cd87ef6 sis900: fix warning in drivers/net/sis900.c
this warning:

  drivers/net/sis900.c: In function ‘sis900_timer’:
  drivers/net/sis900.c:1280: warning: ‘speed’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between sis900_read_mode(), 'speed' and 'duplex'.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:52:13 -08:00
Ingo Molnar
180b65df7b fix warning in fs/dlm/netlink.c
this warning:

  fs/dlm/netlink.c: In function ‘dlm_timeout_warn’:
  fs/dlm/netlink.c:131: warning: ‘send_skb’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between prepare_data() and send_skb.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:51:45 -08:00
Ingo Molnar
d3f644da90 dsa: fix warning in net/dsa/mv88e6060.c
this warning:

  net/dsa/mv88e6060.c: In function ‘mv88e6060_poll_link’:
  net/dsa/mv88e6060.c:225: warning: ‘port_status’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between 'link' and 'port_status'.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:51:13 -08:00
Ingo Molnar
2a9e79782d dsa: fix warning in net/dsa/mv88e6xxx.c
this warning:

  net/dsa/mv88e6xxx.c: In function ‘mv88e6xxx_poll_link’:
  net/dsa/mv88e6xxx.c:361: warning: ‘port_status’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between 'link' and 'port_status'.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:50:49 -08:00
Ingo Molnar
55205d400e ipv6: fix warning in net/ipv6/ip6_flowlabel.c
this warning:

  net/ipv6/ip6_flowlabel.c: In function ‘ipv6_flowlabel_opt’:
  net/ipv6/ip6_flowlabel.c:467: warning: ‘err’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between fl_create() and 'err'.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:50:30 -08:00
Ingo Molnar
dc0a0011cf pkt_sched: fix warning in net/sched/sch_hfsc.c
this warning:

  net/sched/sch_hfsc.c: In function ‘hfsc_enqueue’:
  net/sched/sch_hfsc.c:1577: warning: ‘err’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between hfsc_classify(), 'cl' and 'err'.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:50:02 -08:00
Ingo Molnar
ed72b9c6e0 sunrpc: fix warning in net/sunrpc/xprtrdma/svc_rdma_transport.c
this warning:

  net/sunrpc/xprtrdma/svc_rdma_transport.c: In function ‘svc_rdma_accept’:
  net/sunrpc/xprtrdma/svc_rdma_transport.c:830: warning: ‘dma_mr_acc’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) flow connection
between need_dma_mr and dma_mr_acc.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:49:37 -08:00
Ingo Molnar
be5a3c62c8 qla3xxx: fix warning in drivers/net/qla3xxx.c
this warning:

  drivers/net/qla3xxx.c: In function ‘ql3xxx_probe’:
  drivers/net/qla3xxx.c:3912: warning: ‘pci_using_dac’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between 'pci_using_dac' and 'err'.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:49:07 -08:00
Ingo Molnar
f166400bd4 niu: fix another warning in drivers/net/niu.c
this warning:

  drivers/net/niu.c: In function ‘esr_reset’:
  drivers/net/niu.c:741: warning: ‘reset’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between:

 - esr_read_reset() and 'reset'

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:48:42 -08:00
Ingo Molnar
51e0f058c4 niu: fix warnings in drivers/net/niu.c
these warnings:

  drivers/net/niu.c: In function ‘serdes_init_niu_1g_serdes’:
  drivers/net/niu.c:451: warning: ‘sig’ may be used uninitialized in this function
  drivers/net/niu.c: In function ‘serdes_init_niu_10g_serdes’:
  drivers/net/niu.c:550: warning: ‘sig’ may be used uninitialized in this function

triggers because GCC does not recognize that the max_retry loop
always initializes 'sig', due to max_retry != 0.

Annotate them.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:48:12 -08:00
Ingo Molnar
2e6a684b84 s2io: fix warning in drivers/net/s2io.c
this warning:

  drivers/net/s2io.c: In function ‘rx_intr_handler’:
  drivers/net/s2io.c:7369: warning: ‘lro’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) error flow
between:

 - s2io_club_tcp_session()and 'lro'

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:47:35 -08:00
Daniel Lezcano
09bb52175b netns: filter out uevent not belonging to init_net
This patch will filter out the uevent not related to the init_net.
Without this patch if a network device is created in a network
namespace with the same name as one network device belonging to the
initial network namespace (eg. eth0), when the network namespace
will die and the network device will be destroyed, an event will
be sent and catched by the udevd daemon. That will result to have
the real network device to be shutdown because the udevd/uevent are
not namespace aware.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:46:37 -08:00
Robert Olsson
cb13fc209f ixgbe: Naming interrupt vectors
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Acked-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:44:39 -08:00
Robert Olsson
70340d728f niu: Naming interrupt vectors.
A patch to put names on the niu interrupt vectors according the syntax below.
 This is needed to assign correct affinity.

 > So on a multiqueue card with 2 RX queues and 2 TX queues we'd
 > have names like:
 >
 > 	eth0-rx-0
 > 	eth0-rx-1
 > 	eth0-tx-0
 > 	eth0-tx-1

Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Tested-by: Jesper Dangaard Brouer <jdb@comx.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 16:44:38 -08:00
Ilpo Järvinen
9f782db3f5 tcp: skb_shift cannot cache frag ptrs past pskb_expand_head
Since pskb_expand_head creates copy of the shared area we
cannot keep any frag ptr past de-cloning. This fixes the
tcpdump recvfrom -EFAULT problem.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 13:57:01 -08:00
Jarek Poplawski
f6486d40b3 pkt_sched: sch_api: Remove qdisc_list_lock
After implementing qdisc->ops->peek() there is no more calling
qdisc_tree_decrease_qlen() without rtnl_lock(), so qdisc_list_lock
added by commit: f6e0b239a2 "pkt_sched:
Fix qdisc list locking" can be removed.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 13:56:06 -08:00
Eric Dumazet
723b46108f net: udp_unhash() can test if sk is hashed
Impact: Optimization

Like done in inet_unhash(), we can avoid taking a chain lock if
socket is not hashed in udp_unhash()

Triggered by close(socket(AF_INET, SOCK_DGRAM, 0));

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 13:55:15 -08:00
Eric Dumazet
5bc0b3bfa7 net: Make sure BHs are disabled in sock_prot_inuse_add()
prot->destroy is not called with BH disabled. So we must add
explicit BH disable around call to sock_prot_inuse_add()
in sctp_destroy_sock()

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 13:53:27 -08:00
Ilpo Järvinen
8eecaba900 tcp: tcp_limit_reno_sacked can become static
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 13:45:29 -08:00
David S. Miller
2f9889a20c Revert "hso: Fix crashes on close."
This reverts commit 4a3e818181.

On request from Alan Cox.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 03:53:09 -08:00
David S. Miller
ab153d84d9 Revert "hso: Fix free of mutexes still in use."
This reverts commit 52429eb216.

On request from Alan Cox.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 03:52:46 -08:00
David S. Miller
cd90ee1799 Revert "hso: Add TIOCM ioctl handling."
This reverts commit 7ea3a9ad9b.

On request from Alan Cox.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 03:52:17 -08:00
Alexey Dobriyan
fb7e06748c xfrm: remove useless forward declarations
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 01:05:54 -08:00
Alexey Dobriyan
6daad37230 ah4/ah6: remove useless NULL assignments
struct will be kfreed in a moment, so...

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 01:05:09 -08:00
Alexander Duyck
69d728baf6 igb: loopback bits not correctly cleared from RCTL register
This change forces the bits to 0 by using an &= operation with an inverted
mask of all options instead of using an |= with a value of 0.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 01:04:03 -08:00
Alexander Duyck
9b07f3d315 igb: remove unneeded bit refrence when enabling jumbo frames
There is a reference to a Buffer Size extention bit that is unneded by
82575/82576 hardware.  Since it is not needed it should be removed from the
code.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 01:03:26 -08:00
Jeff Kirsher
7a6b6f515f DCB: fix kconfig option
Since the netlink option for DCB is necessary to actually be useful,
simplified the Kconfig option.  In addition, added useful help text for the
Kconfig option.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 01:02:08 -08:00
Harvey Harrison
411c41eea5 aoe: remove private mac address format function
Add %pm to omit the colons when printing a mac address.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:40:37 -08:00
Denis Joseph Barrow
9c8f92aed1 hso: Hook up ->reset_resume
Made usb_drivers reset_resume function point to hso_resume this 
fixes problems a usb reset is done when the network interface
is left idle for a few minutes. Possibly reset_resume should
initialise hardware more but this works in the common case.

Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:36:10 -08:00
Denis Joseph Barrow
7ea3a9ad9b hso: Add TIOCM ioctl handling.
Makes TIOCM ioctls for Data Carrier Detect & related functions
work like /drivers/serial/serial-core.c potentially needed 
for pppd & similar user programs.   

Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:35:26 -08:00
Denis Joseph Barrow
52429eb216 hso: Fix free of mutexes still in use.
A new structure hso_mutex_table had to be declared statically
& used as as hso_device mutex_lock(&serial->parent->mutex) etc
is freed in hso_serial_open & hso_serial_close by kref_put while
the mutex is still in use.

This is a substantial change but should make the driver much stabler.

Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:33:13 -08:00
Denis Joseph Barrow
89930b7b5e hso: Fix URB submission -EINVAL.
Added check for IFF_UP in hso_resume, this should eliminate -EINVAL (-22)
errors caused from urb's being submitted twice, once by hso_resume
& once in hso_net_open, if suspend/resume USB power saving  mode is enabled

Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:30:48 -08:00
Denis Joseph Barrow
4a3e818181 hso: Fix crashes on close.
Moved serial_open_count in hso_serial_open to
prevent crashes owing to the serial structure being made NULL
when hso_serial_close is called even though hso_serial_open
returned -ENODEV, Alan Cox pointed out this happens,
also put in sanity check in hso_serial_close
to check for a valid serial structure which should prevent
the most reproducable crash in the driver when the hso device
is disconnected while in use.

Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:27:50 -08:00
Denis Joseph Barrow
bab04c3adb hso: Add new usb device id's.
Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:26:12 -08:00
Stephen Hemminger
47fd5b8373 netdev: add HAVE_NET_DEVICE_OPS
As a concession to vendors who have to deal with one source for different
kernel versions, add a HAVE_NET_DEVICE_OPS so they don't end up hard
coding ifdef against kernel version.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:20:43 -08:00
Ilpo Järvinen
0ace285605 tcp: handle shift/merge of cloned skbs too
This caused me to get repeatably:

  tcpdump: pcap_loop: recvfrom: Bad address

Happens occassionally when I tcpdump my for-looped test xfers:
  while [ : ]; do echo -n "$(date '+%s.%N') "; ./sendfile; sleep 20; done

Rest of the relevant commands:
  ethtool -K eth0 tso off
  tc qdisc add dev eth0 root netem drop 4%
  tcpdump -n -s0 -i eth0 -w sacklog.all

Running net-next under kvm, connection goes to the same host
(basically just out of kvm). The connection itself works ok
and data gets sent without corruption even with a large
number of tests while tcpdump fails usually within less than
5 tests.

Whether it only happens because of this change or not, I
don't know for sure but it's the only thing with which
I've seen that error. The non-cloned variant works w/o it
for much longer time. I'm yet to debug where the error
actually comes from.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-24 21:30:21 -08:00
Ilpo Järvinen
111cc8b913 tcp: add some mibs to track collapsing
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-24 21:27:22 -08:00
Ilpo Järvinen
92ee76b6d9 tcp: Make shifting not clear the hints
The earlier version was just very basic one which is "playing
safe" by always clearing the hints. However, clearing of a hint
is extremely costly operation with large windows, so it must be
avoided at all cost whenever possible, there is a way with
shifting too achieve not-clearing.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-24 21:26:56 -08:00
Ilpo Järvinen
832d11c5cd tcp: Try to restore large SKBs while SACK processing
During SACK processing, most of the benefits of TSO are eaten by
the SACK blocks that one-by-one fragment SKBs to MSS sized chunks.
Then we're in problems when cleanup work for them has to be done
when a large cumulative ACK comes. Try to return back to pre-split
state already while more and more SACK info gets discovered by
combining newly discovered SACK areas with the previous skb if
that's SACKed as well.

This approach has a number of benefits:

1) The processing overhead is spread more equally over the RTT
2) Write queue has less skbs to process (affect everything
   which has to walk in the queue past the sacked areas)
3) Write queue is consistent whole the time, so no other parts
   of TCP has to be aware of this (this was not the case with
   some other approach that was, well, quite intrusive all
   around).
4) Clean_rtx_queue can release most of the pages using single
   put_page instead of previous PAGE_SIZE/mss+1 calls

In case a hole is fully filled by the new SACK block, we attempt
to combine the next skb too which allows construction of skbs
that are even larger than what tso split them to and it handles
hole per on every nth patterns that often occur during slow start
overshoot pretty nicely. Though this to be really useful also
a retransmission would have to get lost since cumulative ACKs
advance one hole at a time in the most typical case.

TODO: handle upwards only merging. That should be rather easy
when segment is fully sacked but I'm leaving that as future
work item (it won't make very large difference anyway since
this current approach already covers quite a lot of normal
cases).

I was earlier thinking of some sophisticated way of tracking
timestamps of the first and the last segment but later on
realized that it won't be that necessary at all to store the
timestamp of the last segment. The cases that can occur are
basically either:
  1) ambiguous => no sensible measurement can be taken anyway
  2) non-ambiguous is due to reordering => having the timestamp
     of the last segment there is just skewing things more off
     than does some good since the ack got triggered by one of
     the holes (besides some substle issues that would make
     determining right hole/skb even harder problem). Anyway,
     it has nothing to do with this change then.

I choose to route some abnormal looking cases with goto noop,
some could be handled differently (eg., by stopping the
walking at that skb but again). In general, they either
shouldn't happen at all or are rare enough to make no difference
in practice.

In theory this change (as whole) could cause some macroscale
regression (global) because of cache misses that are taken over
the round-trip time but it gets very likely better because of much
less (local) cache misses per other write queue walkers and the
big recovery clearing cumulative ack.

Worth to note that these benefits would be very easy to get also
without TSO/GSO being on as long as the data is in pages so that
we can merge them. Currently I won't let that happen because
DSACK splitting at fragment that would mess up pcounts due to
sk_can_gso in tcp_set_skb_tso_segs. Once DSACKs fragments gets
avoided, we have some conditions that can be made less strict.

TODO: I will probably have to convert the excessive pointer
passing to struct sacktag_state... :-)

My testing revealed that considerable amount of skbs couldn't
be shifted because they were cloned (most likely still awaiting
tx reclaim)...

[The rest is considering future work instead since I got
repeatably EFAULT to tcpdump's recvfrom when I added
pskb_expand_head to deal with clones, so I separated that
into another, later patch]

...To counter that, I gave up on the fifth advantage:

5) When growing previous SACK block, less allocs for new skbs
   are done, basically a new alloc is needed only when new hole
   is detected and when the previous skb runs out of frags space

...which now only happens of if reclaim is fast enough to dispose
the clone before the SACK block comes in (the window is RTT long),
otherwise we'll have to alloc some.

With clones being handled I got these numbers (will be somewhat
worse without that), taken with fine-grained mibs:

                  TCPSackShifted 398
                   TCPSackMerged 877
            TCPSackShiftFallback 320
      TCPSACKCOLLAPSEFALLBACKGSO 0
  TCPSACKCOLLAPSEFALLBACKSKBBITS 0
  TCPSACKCOLLAPSEFALLBACKSKBDATA 0
    TCPSACKCOLLAPSEFALLBACKBELOW 0
    TCPSACKCOLLAPSEFALLBACKFIRST 1
 TCPSACKCOLLAPSEFALLBACKPREVBITS 318
      TCPSACKCOLLAPSEFALLBACKMSS 1
   TCPSACKCOLLAPSEFALLBACKNOHEAD 0
    TCPSACKCOLLAPSEFALLBACKSHIFT 0
          TCPSACKCOLLAPSENOOPSEQ 0
  TCPSACKCOLLAPSENOOPSMALLPCOUNT 0
     TCPSACKCOLLAPSENOOPSMALLLEN 0
             TCPSACKCOLLAPSEHOLE 12

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-24 21:20:15 -08:00
Ilpo Järvinen
f58b22fd3c tcp: make tcp_sacktag_one able to handle partial skb too
This is preparatory work for SACK combiner patch which may
have to count TCP state changes for only a part of the skb
because it will intentionally avoids splitting skb to SACKed
and not sacked parts.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-24 21:14:43 -08:00
Ilpo Järvinen
adb92db857 tcp: Make SACK code to split only at mss boundaries
Sadly enough, this adds possible divide though we try to avoid
it by checking one mss as common case.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-24 21:13:50 -08:00