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sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts. They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve". __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".
Over time, callers had a requirement to not block when fallback options
were available. Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.
This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative. High priority users continue to use
__GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim. __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.
This patch then converts a number of sites
o __GFP_ATOMIC is used by callers that are high priority and have memory
pools for those requests. GFP_ATOMIC uses this flag.
o Callers that have a limited mempool to guarantee forward progress clear
__GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
into this category where kswapd will still be woken but atomic reserves
are not used as there is a one-entry mempool to guarantee progress.
o Callers that are checking if they are non-blocking should use the
helper gfpflags_allow_blocking() where possible. This is because
checking for __GFP_WAIT as was done historically now can trigger false
positives. Some exceptions like dm-crypt.c exist where the code intent
is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
flag manipulations.
o Callers that built their own GFP flags instead of starting with GFP_KERNEL
and friends now also need to specify __GFP_KSWAPD_RECLAIM.
The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.
The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL. They may
now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Minor overlapping changes in net/ipv4/ipmr.c, in 'net' we were
fixing the "BH-ness" of the counter bumps whilst in 'net-next'
the functions were modified to take an explicit 'net' parameter.
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211
Johannes Berg says:
====================
Another set of fixes:
* remove a warning on a check that can trigger without any
errors having happened (Andrei)
* correctly handle deauth request while in the process of
associating (Andrei)
* fix TDLS HT operation (Arik)
* allow changing AID/listen interval during client setup (Ayala)
* be more forgiving with WMM parameters to get HT/VHT in case of
broken APs with bad WMM settings (Emmanuel, myself)
* a number of other fixes (some in documentation)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Channel context driver operations can sleep, so add might_sleep()
and document this.
Signed-off-by: Chaitanya T K <chaitanya.mgit@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The previous patch changed mac80211 to always report an event
after a CQM RSSI reconfiguration. Document that as expected
behaviour in both the cfg80211 and mac80211 API.
Currently, iwlmvm already implements that behaviour; the other
drivers implementing CQM RSSI events may have to be changed.
This behaviour lets userspace know what the current state is
without relying on querying the data which is racy.
Reviewed-by: Sharon, Sara <sara.sharon@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Old logic of updating state-machine is not required since
ad_update_actor_keys() does it implicitly. The only loss is
the notification differentiation between speed vs. duplex
change. Now only one unified notification is printed.
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch fixes following problems :
1) percpu_counter_init() can return an error, therefore
init_frag_mem_limit() must propagate this error so that
inet_frags_init_net() can do the same up to its callers.
2) If ip[46]_frags_ns_ctl_register() fail, we must unwind
properly and free the percpu_counter.
Without this fix, we leave freed object in percpu_counters
global list (if CONFIG_HOTPLUG_CPU) leading to crashes.
This bug was detected by KASAN and syzkaller tool
(http://github.com/google/syzkaller)
Fixes: 6d7b857d541e ("net: use lib/percpu_counter API for fragmentation mem accounting")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Under low memory conditions, tcp_sk_init() and icmp_sk_init()
can both iterate on all possible cpus and call inet_ctl_sock_destroy(),
with eventual NULL pointer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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skb_set_owner_w() is called from various places that assume
skb->sk always point to a full blown socket (as it changes
sk->sk_wmem_alloc)
We'd like to attach skb to request sockets, and in the future
to timewait sockets as well. For these kind of pseudo sockets,
we need to take a traditional refcount and use sock_edemux()
as the destructor.
It is now time to un-inline skb_set_owner_w(), being too big.
Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Bisected-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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When fib_netdev_event calls fib_disable_ip on NETDEV_DOWN event
we should not delete the local routes if the local address
is still present. The confusion comes from the fact that both
fib_netdev_event and fib_inetaddr_event use the NETDEV_DOWN
constant. Fix it by returning back the variable 'force'.
Steps to reproduce:
modprobe dummy
ifconfig dummy0 192.168.168.1 up
ifconfig dummy0 down
ip route list table local | grep dummy | grep host
local 192.168.168.1 dev dummy0 proto kernel scope host src 192.168.168.1
Fixes: 8a3d03166f19 ("net: track link-status of ipv4 nexthops")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Simplify DSA by pushing the switchdev objects for VLAN add and delete
operations down to its drivers. Currently only mv88e6xxx is affected.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The SS_LISTEN socket state is defined by both af_vsock.c and
vmci_transport.c. This is risky since the value could be changed in one
file and the other would be out of sync.
Rename from SS_LISTEN to VSOCK_SS_LISTEN since the constant is not part
of enum socket_state (SS_CONNECTED, ...). This way it is clear that the
constant is vsock-specific.
The big text reflow in af_vsock.c was necessary to keep to the maximum
line length. Text is unchanged except for s/SS_LISTEN/VSOCK_SS_LISTEN/.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/sameo/nfc-next
Samuel Ortiz says:
====================
NFC 4.4 pull request
This is the NFC pull request for 4.4.
It's a bit bigger than usual, the 3 main culprits being:
- A new driver for Intel's Fields Peak NCI chipset. In order to
support this chipset we had to export a few NCI routines and
extend the driver NCI ops to not only support proprietary
commands but also core ones.
- Support for vendor commands for both STM drivers, st-nci
and st21nfca. Those vendor commands allow to run factory tests
through the NFC netlink interface.
- New i2c and SPI support for the Marvell driver, together with
firmware download support for this driver's core.
Besides that we also have:
- A few file renames in the STM drivers, to keep the naming
consistent between drivers.
- Some improvements and fixes on the NCI HCI layer, mostly to
properly reach a secure element over a legacy HCI link.
- A few fixes for the s3fwrn5 and trf7970a drivers.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next
Johan Hedberg says:
====================
pull request: bluetooth-next 2015-10-28
Here are a some more Bluetooth patches for 4.4 which collected up during
the past week. The most important ones are from Kuba Pawlak for fixing
locking issues with SCO sockets. There's also a fix from Alexander Aring
for 6lowpan, a memleak fix from Julia Lawall for the btmrvl driver and
some cleanup patches from Marcel.
Please let me know if there are any issues pulling. Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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This fixes a build error that seems to be toochain
dependent (Not seen with gcc v5.1):
In file included from net/nfc/nci/rsp.c:36:0:
net/nfc/nci/rsp.c: In function ‘nci_rsp_packet’:
include/net/nfc/nci_core.h:355:12: error: inlining failed in call to
always_inline ‘nci_prop_rsp_packet’: function body not available
inline int nci_prop_rsp_packet(struct nci_dev *ndev, __u16 opcode,
Signed-off-by: Robert Dolca <robert.dolca@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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Adding IPv6 for the TSO helper API is trivial:
* Don't play with the id (which doesn't exist in IPv6)
* Correctly update the payload_len (don't include the
length of the IP header itself)
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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In some cases low level drivers might want to update the
SPI transfer clock (e.g. during firmware download).
This patch adds this support. Without any modification the
driver will use the default SPI clock (from pdata or device tree).
Signed-off-by: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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This driver adds the support of I2C-based Marvell NFC controller.
Signed-off-by: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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Export nci_send_frame and nci_send_cmd symbols to allow drivers
to use it. This is needed for example if NCI is used during
firmware download phase.
Signed-off-by: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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In order to manage in a better way the nci poll mode state machine,
add mode parameter to deactivate_target functions.
This way we can manage different target state.
mode parameter make sense only in nci core.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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Add support for proprietary commands useful mainly for
factory testings. Here is a list:
- FACTORY_MODE: Allow to set the driver into a mode where
no secure element are activated. It does not consider any
NFC_ATTR_VENDOR_DATA.
- HCI_CLEAR_ALL_PIPES: Allow to execute a HCI clear all pipes
command. It does not consider any NFC_ATTR_VENDOR_DATA.
- HCI_DM_PUT_DATA: Allow to configure specific CLF registry
like for example RF trimmings or low level drivers
configurations (I2C, SPI, SWP).
- HCI_DM_UPDATE_AID: Allow to configure an AID routing into the
CLF routing table following RF technology, CLF mode or protocol.
- HCI_DM_GET_INFO: Allow to retrieve CLF information.
- HCI_DM_GET_DATA: Allow to retrieve CLF configurable data such as
low level drivers configurations or RF trimmings.
- HCI_DM_DIRECT_LOAD: Allow to load a firmware into the CLF.
A complete packet can be more than 8KB.
- HCI_DM_RESET: Allow to run a CLF reset in order to "commit" CLF
configuration changes without CLF power off.
- HCI_GET_PARAM: Allow to retrieve an HCI CLF parameter (for example
the white list).
- HCI_DM_FIELD_GENERATOR: Allow to generate different kind of RF
technology. When using this command to anti-collision is done.
- HCI_LOOPBACK: Allow to echo a command and test the Dh to CLF
connectivity.
- HCI_DM_VDC_MEASUREMENT_VALUE: Allow to measure the field applied
on the CLF antenna. A value between 0 and 0x0f is returned. 0 is
maximum.
- HCI_DM_FWUPD_START: Allow to put CLF into firmware update mode.
It is a specific CLF command as there is no GPIO for this.
- HCI_DM_FWUPD_END: Allow to complete firmware update.
- HCI_DM_VDC_VALUE_COMPARISON: Allow to compare the field applied
on the CLF antenna to a reference value.
- MANUFACTURER_SPECIFIC: Allow to retrieve manufacturer specific data
received during a NCI_CORE_INIT_CMD.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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The SKB context buffer for HCI request is really not just for requests,
information in their are preserved for the whole HCI layer. So it makes
more sense to actually rename it into bt_cb()->hci and also call it then
struct hci_ctrl.
In addition that allows moving the decoded opcode for outgoing packets
into that struct. So far it was just consuming valuable space from the
main shared items. And opcode are not valid for L2CAP packets.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
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NCI_HCI_IDENTITY_MGMT_GATE might be useful to get information
about hardware or firmware version.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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nci_hci_clear_all_pipes might be use full in some cases
for example after a firmware update.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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This functin takes as a parameter a pointer to the nci_dev
struct and the first byte from the values of the first domain
specific parameter that was used for the connection creation.
Signed-off-by: Robert Dolca <robert.dolca@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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Initially it was used to create hooks in the driver for
proprietary operations. Currently it is being used for hooks
for both proprietary and generic operations.
Signed-off-by: Robert Dolca <robert.dolca@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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The driver may be required to act when some responses or
notifications arrive. For example the NCI core does not have a
handler for NCI_OP_CORE_GET_CONFIG_RSP. The NFCC can send a
config response that has to be read by the driver and the packet
may contain vendor specific data.
The Fields Peak driver needs to take certain actions when a reset
notification arrives (packet also not handled by the nfc core).
The driver handlers do not interfere with the core and they are
called after the core processes the packet.
Signed-off-by: Robert Dolca <robert.dolca@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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This allows sending core commands from the driver. The driver
should be able to send NCI core commands like CORE_GET_CONFIG_CMD.
Signed-off-by: Robert Dolca <robert.dolca@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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Add NCI_OP_CORE_GET_CONFIG_CMD, NCI_OP_CORE_GET_CONFIG_RSP
and NCI_OP_CORE_RESET_NTF.
Signed-off-by: Robert Dolca <robert.dolca@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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FDP driver needs to send the firmware as regular packets
(not fragmented). The driver should have a way to
get the max packet size for a given connection.
Signed-off-by: Robert Dolca <robert.dolca@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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Conflicts:
net/ipv6/xfrm6_output.c
net/openvswitch/flow_netlink.c
net/openvswitch/vport-gre.c
net/openvswitch/vport-vxlan.c
net/openvswitch/vport.c
net/openvswitch/vport.h
The openvswitch conflicts were overlapping changes. One was
the egress tunnel info fix in 'net' and the other was the
vport ->send() op simplification in 'net-next'.
The xfrm6_output.c conflicts was also a simplification
overlapping a bug fix.
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next
Johan Hedberg says:
====================
pull request: bluetooth-next 2015-10-22
Here's probably the last bluetooth-next pull request for 4.4. Among
several other changes it contains the rest of the fixes & cleanups from
the Bluetooth UnplugFest (that didn't need to be hurried to 4.3).
- Refactoring & cleanups to 6lowpan code
- New USB ids for two Atheros controllers and BCM43142A0 from Broadcom
- Fix (quirk) for broken Broadcom BCM2045 controllers
- Support for latest Apple controllers
- Improvements to the vendor diagnostic message support
Please let me know if there are any issues pulling. Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch adds support for MPLS multipath routes.
Includes following changes to support multipath:
- splits struct mpls_route into 'struct mpls_route + struct mpls_nh'
- 'struct mpls_nh' represents a mpls nexthop label forwarding entry
- moves mpls route and nexthop structures into internal.h
- A mpls_route can point to multiple mpls_nh structs
- the nexthops are maintained as a array (similar to ipv4 fib)
- In the process of restructuring, this patch also consistently changes
all labels to u8
- Adds support to parse/fill RTA_MULTIPATH netlink attribute for
multipath routes similar to ipv4/v6 fib
- In this patch, the multipath route nexthop selection algorithm
simply returns the first nexthop. It is replaced by a
hash based algorithm from Robert Shearman in the next patch
- mpls_route_update cleanup: remove 'dev' handling in mpls_route_update.
mpls_route_update though implemented to update based on dev, it was
never used that way. And the dev handling gets tricky with multiple
nexthops. Cannot match against any single nexthops dev. So, this patch
removes the unused 'dev' handling in mpls_route_update.
- dead route/path handling will be implemented in a subsequent patch
Example:
$ip -f mpls route add 100 nexthop as 200 via inet 10.1.1.2 dev swp1 \
nexthop as 700 via inet 10.1.1.6 dev swp2 \
nexthop as 800 via inet 40.1.1.2 dev swp3
$ip -f mpls route show
100
nexthop as to 200 via inet 10.1.1.2 dev swp1
nexthop as to 700 via inet 10.1.1.6 dev swp2
nexthop as to 800 via inet 40.1.1.2 dev swp3
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Acked-by: Robert Shearman <rshearma@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Multiple cpus can process duplicates of incoming ACK messages
matching a SYN_RECV request socket. This is a rare event under
normal operations, but definitely can happen.
Only one must win the race, otherwise corruption would occur.
To fix this without adding new atomic ops, we use logic in
inet_ehash_nolisten() to detect the request was present in the same
ehash bucket where we try to insert the new child.
If request socket was not found, we have to undo the child creation.
This actually removes a spin_lock()/spin_unlock() pair in
reqsk_queue_unlink() for the fast path.
Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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While transitioning to netdev based vport we broke OVS
feature which allows user to retrieve tunnel packet egress
information for lwtunnel devices. Following patch fixes it
by introducing ndo operation to get the tunnel egress info.
Same ndo operation can be used for lwtunnel devices and compat
ovs-tnl-vport devices. So after adding such device operation
we can remove similar operation from ovs-vport.
Fixes: 614732eaa12d ("openvswitch: Use regular VXLAN net_device device").
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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No driver implements port_fdb_getnext anymore, and port_fdb_dump is
preferred anyway, so remove this function from DSA.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Not all switch chips support a Get Next operation to iterate on its FDB.
So add a more simple port_fdb_dump function for them.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next
Johannes Berg says:
====================
Here's another set of patches for the current cycle:
* I merged net-next back to avoid a conflict with the
* cfg80211 scheduled scan API extensions
* preparations for better scan result timestamping
* regulatory cleanups
* mac80211 statistics cleanups
* a few other small cleanups and fixes
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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if_nlmsg_size() overestimates the minimum allocation size of netlink
dump request (when called from rtnl_calcit()) or the size of the
message (when called from rtnl_getlink()). This is because
ext_filter_mask is not supported by rtnl_link_get_af_size() and
rtnl_link_get_size().
The over-estimation is significant when at least one netdev has many
VLANs configured (8 bytes for each configured VLAN).
This patch-set "rightsizes" the protocol specific attribute size
calculation by propagating ext_filter_mask to rtnl_link_get_af_size()
and adding this a argument to get_link_af_size op in rtnl_af_ops.
Bridge module already used filtering aware sizing for notifications.
br_get_link_af_size_filtered() is consistent with the modified
get_link_af_size op so it replaces br_get_link_af_size() in br_af_ops.
br_get_link_af_size() becomes unused and thus removed.
Signed-off-by: Ronen Arad <ronen.arad@intel.com>
Acked-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There's only one user of this helper which can be replaces with a call
to hci_pend_le_action_lookup() and a check for params->explicit_connect.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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Many of the existing LE connection lookups are forced to use
hci_conn_hash_lookup_ba() which doesn't take into account the address
type. What's worse, most of the users don't bother checking that the
returned address type matches what was wanted.
This patch adds a new helper API to look up LE connections based on
their address and address type, paving the way to have the
hci_conn_hash_lookup_ba() users converted to do more precise lookups.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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This patch implements the second half of RACK that uses the the most
recent transmit time among all delivered packets to detect losses.
tcp_rack_mark_lost() is called upon receiving a dubious ACK.
It then checks if an not-yet-sacked packet was sent at least
"reo_wnd" prior to the sent time of the most recently delivered.
If so the packet is deemed lost.
The "reo_wnd" reordering window starts with 1msec for fast loss
detection and changes to min-RTT/4 when reordering is observed.
We found 1msec accommodates well on tiny degree of reordering
(<3 pkts) on faster links. We use min-RTT instead of SRTT because
reordering is more of a path property but SRTT can be inflated by
self-inflicated congestion. The factor of 4 is borrowed from the
delayed early retransmit and seems to work reasonably well.
Since RACK is still experimental, it is now used as a supplemental
loss detection on top of existing algorithms. It is only effective
after the fast recovery starts or after the timeout occurs. The
fast recovery is still triggered by FACK and/or dupack threshold
instead of RACK.
We introduce a new sysctl net.ipv4.tcp_recovery for future
experiments of loss recoveries. For now RACK can be disabled by
setting it to 0.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch is the first half of the RACK loss recovery.
RACK loss recovery uses the notion of time instead
of packet sequence (FACK) or counts (dupthresh). It's inspired by the
previous FACK heuristic in tcp_mark_lost_retrans(): when a limited
transmit (new data packet) is sacked, then current retransmitted
sequence below the newly sacked sequence must been lost,
since at least one round trip time has elapsed.
But it has several limitations:
1) can't detect tail drops since it depends on limited transmit
2) is disabled upon reordering (assumes no reordering)
3) only enabled in fast recovery ut not timeout recovery
RACK (Recently ACK) addresses these limitations with the notion
of time instead: a packet P1 is lost if a later packet P2 is s/acked,
as at least one round trip has passed.
Since RACK cares about the time sequence instead of the data sequence
of packets, it can detect tail drops when later retransmission is
s/acked while FACK or dupthresh can't. For reordering RACK uses a
dynamically adjusted reordering window ("reo_wnd") to reduce false
positives on ever (small) degree of reordering.
This patch implements tcp_advanced_rack() which tracks the
most recent transmission time among the packets that have been
delivered (ACKed or SACKed) in tp->rack.mstamp. This timestamp
is the key to determine which packet has been lost.
Consider an example that the sender sends six packets:
T1: P1 (lost)
T2: P2
T3: P3
T4: P4
T100: sack of P2. rack.mstamp = T2
T101: retransmit P1
T102: sack of P2,P3,P4. rack.mstamp = T4
T205: ACK of P4 since the hole is repaired. rack.mstamp = T101
We need to be careful about spurious retransmission because it may
falsely advance tp->rack.mstamp by an RTT or an RTO, causing RACK
to falsely mark all packets lost, just like a spurious timeout.
We identify spurious retransmission by the ACK's TS echo value.
If TS option is not applicable but the retransmission is acknowledged
less than min-RTT ago, it is likely to be spurious. We refrain from
using the transmission time of these spurious retransmissions.
The second half is implemented in the next patch that marks packet
lost using RACK timestamp.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Kathleen Nichols' algorithm for tracking the minimum RTT of a
data stream over some measurement window. It uses constant space
and constant time per update. Yet it almost always delivers
the same minimum as an implementation that has to keep all
the data in the window. The measurement window is tunable via
sysctl.net.ipv4.tcp_min_rtt_wlen with a default value of 5 minutes.
The algorithm keeps track of the best, 2nd best & 3rd best min
values, maintaining an invariant that the measurement time of
the n'th best >= n-1'th best. It also makes sure that the three
values are widely separated in the time window since that bounds
the worse case error when that data is monotonically increasing
over the window.
Upon getting a new min, we can forget everything earlier because
it has no value - the new min is less than everything else in the
window by definition and it's the most recent. So we restart fresh
on every new min and overwrites the 2nd & 3rd choices. The same
property holds for the 2nd & 3rd best.
Therefore we have to maintain two invariants to maximize the
information in the samples, one on values (1st.v <= 2nd.v <=
3rd.v) and the other on times (now-win <=1st.t <= 2nd.t <= 3rd.t <=
now). These invariants determine the structure of the code
The RTT input to the windowed filter is the minimum RTT measured
from ACK or SACK, or as the last resort from TCP timestamps.
The accessor tcp_min_rtt() returns the minimum RTT seen in the
window. ~0U indicates it is not available. The minimum is 1usec
even if the true RTT is below that.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The hci_conn objects don't have a dedicated lock themselves but rely
on the caller to hold the hci_dev lock for most types of access. The
hci_conn_timeout() function has so far sent certain HCI commands based
on the hci_conn state which has been possible without holding the
hci_dev lock.
The recent changes to do LE scanning before connect attempts added
even more operations to hci_conn and hci_dev from hci_conn_timeout,
thereby exposing potential race conditions with the hci_dev and
hci_conn states.
As an example of such a race, here there's a timeout but an
l2cap_sock_connect() call manages to race with the cleanup routine:
[Oct21 08:14] l2cap_chan_timeout: chan ee4b12c0 state BT_CONNECT
[ +0.000004] l2cap_chan_close: chan ee4b12c0 state BT_CONNECT
[ +0.000002] l2cap_chan_del: chan ee4b12c0, conn f3141580, err 111, state BT_CONNECT
[ +0.000002] l2cap_sock_teardown_cb: chan ee4b12c0 state BT_CONNECT
[ +0.000005] l2cap_chan_put: chan ee4b12c0 orig refcnt 4
[ +0.000010] hci_conn_drop: hcon f53d56e0 orig refcnt 1
[ +0.000013] l2cap_chan_put: chan ee4b12c0 orig refcnt 3
[ +0.000063] hci_conn_timeout: hcon f53d56e0 state BT_CONNECT
[ +0.000049] hci_conn_params_del: addr ee:0d:30:09:53:1f (type 1)
[ +0.000002] hci_chan_list_flush: hcon f53d56e0
[ +0.000001] hci_chan_del: hci0 hcon f53d56e0 chan f4e7ccc0
[ +0.004528] l2cap_sock_create: sock e708fc00
[ +0.000023] l2cap_chan_create: chan ee4b1770
[ +0.000001] l2cap_chan_hold: chan ee4b1770 orig refcnt 1
[ +0.000002] l2cap_sock_init: sk ee4b3390
[ +0.000029] l2cap_sock_bind: sk ee4b3390
[ +0.000010] l2cap_sock_setsockopt: sk ee4b3390
[ +0.000037] l2cap_sock_connect: sk ee4b3390
[ +0.000002] l2cap_chan_connect: 00:02:72:d9:e5:8b -> ee:0d:30:09:53:1f (type 2) psm 0x00
[ +0.000002] hci_get_route: 00:02:72:d9:e5:8b -> ee:0d:30:09:53:1f
[ +0.000001] hci_dev_hold: hci0 orig refcnt 8
[ +0.000003] hci_conn_hold: hcon f53d56e0 orig refcnt 0
Above the l2cap_chan_connect() shouldn't have been able to reach the
hci_conn f53d56e0 anymore but since hci_conn_timeout didn't do proper
locking that's not the case. The end result is a reference to hci_conn
that's not in the conn_hash list, resulting in list corruption when
trying to remove it later:
[Oct21 08:15] l2cap_chan_timeout: chan ee4b1770 state BT_CONNECT
[ +0.000004] l2cap_chan_close: chan ee4b1770 state BT_CONNECT
[ +0.000003] l2cap_chan_del: chan ee4b1770, conn f3141580, err 111, state BT_CONNECT
[ +0.000001] l2cap_sock_teardown_cb: chan ee4b1770 state BT_CONNECT
[ +0.000005] l2cap_chan_put: chan ee4b1770 orig refcnt 4
[ +0.000002] hci_conn_drop: hcon f53d56e0 orig refcnt 1
[ +0.000015] l2cap_chan_put: chan ee4b1770 orig refcnt 3
[ +0.000038] hci_conn_timeout: hcon f53d56e0 state BT_CONNECT
[ +0.000003] hci_chan_list_flush: hcon f53d56e0
[ +0.000002] hci_conn_hash_del: hci0 hcon f53d56e0
[ +0.000001] ------------[ cut here ]------------
[ +0.000461] WARNING: CPU: 0 PID: 1782 at lib/list_debug.c:56 __list_del_entry+0x3f/0x71()
[ +0.000839] list_del corruption, f53d56e0->prev is LIST_POISON2 (00000200)
The necessary fix is unfortunately more complicated than just adding
hci_dev_lock/unlock calls to the hci_conn_timeout() call path.
Particularly, the hci_conn_del() API, which expects the hci_dev lock to
be held, performs a cancel_delayed_work_sync(&hcon->disc_work) which
would lead to a deadlock if the hci_conn_timeout() call path tries to
acquire the same lock.
This patch solves the problem by deferring the cleanup work to a
separate work callback. To protect against the hci_dev or hci_conn
going away meanwhile temporary references are taken with the help of
hci_dev_hold() and hci_conn_get().
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org # 4.3
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Some drivers might have to restore certain settings after the init
procedure has been completed. This driver callback allows them to hook
into that stage. This callback is run just before the controller is
declared as powered up.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
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This macro is used at 802.15.4 6LoWPAN only and can be replaced by
memcmp with the interface broadcast address.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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This patch removes the IPHC related defines for doing bit manipulation
from global 6lowpan header to the iphc file which should the only one
implementation which use these defines.
Also move next header compression defines to their nhc implementation.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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This patch removes the lowpan_fetch_skb_u8 function for getting the iphc
bytes. Instead we using the generic which has a len parameter to tell
the amount of bytes to fetch.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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This patch changes the lowpan_header_decompress function by removing
inklayer related information from parameters. This is currently for
supporting short and extended address for iphc handling in 802154.
We don't support short address handling anyway right now, but there
exists already code for handling short addresses in
lowpan_header_decompress.
The address parameters are also changed to a void pointer, so 6LoWPAN
linklayer specific code can put complex structures as these parameters
and cast it again inside the generic code by evaluating linklayer type
before. The order is also changed by destination address at first and
then source address, which is the same like all others functions where
destination is always the first, memcpy, dev_hard_header,
lowpan_header_compress, etc.
This patch also moves the fetching of iphc values from 6LoWPAN linklayer
specific code into the generic branch.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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