When queueing a skb to socket, we can immediately release its dst if
target socket do not use IP_CMSG_PKTINFO.
tcp_data_queue() can drop dst too.
This to benefit from a hot cache line and avoid the receiver, possibly
on another cpu, to dirty this cache line himself.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit 95766fff ([UDP]: Add memory accounting.),
each received packet needs one extra sock_lock()/sock_release() pair.
This added latency because of possible backlog handling. Then later,
ticket spinlocks added yet another latency source in case of DDOS.
This patch introduces lock_sock_bh() and unlock_sock_bh()
synchronization primitives, avoiding one atomic operation and backlog
processing.
skb_free_datagram_locked() uses them instead of full blown
lock_sock()/release_sock(). skb is orphaned inside locked section for
proper socket memory reclaim, and finally freed outside of it.
UDP receive path now take the socket spinlock only once.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts two commits:
fda48a0d7a
tcp: bind() fix when many ports are bound
and a follow-on fix for it:
6443bb1fc2
ipv6: Fix inet6_csk_bind_conflict()
It causes problems with binding listening sockets when time-wait
sockets from a previous instance still are alive.
It's too late to keep fiddling with this so late in the -rc
series, and we'll deal with it in net-next-2.6 instead.
Signed-off-by: David S. Miller <davem@davemloft.net>
Current socket backlog limit is not enough to really stop DDOS attacks,
because user thread spend many time to process a full backlog each
round, and user might crazy spin on socket lock.
We should add backlog size and receive_queue size (aka rmem_alloc) to
pace writers, and let user run without being slow down too much.
Introduce a sk_rcvqueues_full() helper, to avoid taking socket lock in
stress situations.
Under huge stress from a multiqueue/RPS enabled NIC, a single flow udp
receiver can now process ~200.000 pps (instead of ~100 pps before the
patch) on a 8 core machine.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Idea from Eric Dumazet.
As for placement inside of struct sock, I tried to choose a place
that otherwise has a 32-bit hole on 64-bit systems.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
RFC 1122 says the following:
...
Keep-alive packets MUST only be sent when no data or
acknowledgement packets have been received for the
connection within an interval.
...
The acknowledgement packet is reseting the keepalive
timer but the data packet isn't. This patch fixes it by
checking the timestamp of the last received data packet
too when the keepalive timer expires.
Signed-off-by: Flavio Leitner <fleitner@redhat.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ipmr /proc interface (ip_mr_cache) can't be extended to dump routes
from any tables but the main table in a backwards compatible fashion since
the output format ends in a variable amount of output interfaces.
Introduce a new netlink interface to dump multicast routes from all tables,
similar to the netlink interface for regular routes.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Decouple rtnetlink address families from real address families in socket.h to
be able to add rtnetlink interfaces to code that is not a real address family
without increasing AF_MAX/NPROTO.
This will be used to add support for multicast route dumping from all tables
as the proc interface can't be extended to support anything but the main table
without breaking compatibility.
This partialy undoes the patch to introduce independant families for routing
rules and converts ipmr routing rules to a new rtnetlink family. Similar to
that patch, values up to 127 are reserved for real address families, values
above that may be used arbitrarily.
Signed-off-by: Patrick McHardy <kaber@trash.net>
fib_rules_register() duplicates the template passed to it without modification,
mark the argument as const. Additionally the templates are only needed when
instantiating a new namespace, so mark them as __net_initdata, which means
they can be discarded when CONFIG_NET_NS=n.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Port autoselection done by kernel only works when number of bound
sockets is under a threshold (typically 30000).
When this threshold is over, we must check if there is a conflict before
exiting first loop in inet_csk_get_port()
Change inet_csk_bind_conflict() to forbid two reuse-enabled sockets to
bind on same (address,port) tuple (with a non ANY address)
Same change for inet6_csk_bind_conflict()
Reported-by: Gaspar Chilingarov <gasparch@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Account for TSO segments of an skb in TCP_MIB_OUTSEGS counter. Without
doing this, the counter can be off by orders of magnitude from the
actual number of segments sent.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Sparse can help us find endianness bugs, but we need to make some
cleanups to be able to more easily spot real bugs.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define a new function to return the waitqueue of a "struct sock".
static inline wait_queue_head_t *sk_sleep(struct sock *sk)
{
return sk->sk_sleep;
}
Change all read occurrences of sk_sleep by a call to this function.
Needed for a future RCU conversion. sk_sleep wont be a field directly
available.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements receive flow steering (RFS). RFS steers
received packets for layer 3 and 4 processing to the CPU where
the application for the corresponding flow is running. RFS is an
extension of Receive Packet Steering (RPS).
The basic idea of RFS is that when an application calls recvmsg
(or sendmsg) the application's running CPU is stored in a hash
table that is indexed by the connection's rxhash which is stored in
the socket structure. The rxhash is passed in skb's received on
the connection from netif_receive_skb. For each received packet,
the associated rxhash is used to look up the CPU in the hash table,
if a valid CPU is set then the packet is steered to that CPU using
the RPS mechanisms.
The convolution of the simple approach is that it would potentially
allow OOO packets. If threads are thrashing around CPUs or multiple
threads are trying to read from the same sockets, a quickly changing
CPU value in the hash table could cause rampant OOO packets--
we consider this a non-starter.
To avoid OOO packets, this solution implements two types of hash
tables: rps_sock_flow_table and rps_dev_flow_table.
rps_sock_table is a global hash table. Each entry is just a CPU
number and it is populated in recvmsg and sendmsg as described above.
This table contains the "desired" CPUs for flows.
rps_dev_flow_table is specific to each device queue. Each entry
contains a CPU and a tail queue counter. The CPU is the "current"
CPU for a matching flow. The tail queue counter holds the value
of a tail queue counter for the associated CPU's backlog queue at
the time of last enqueue for a flow matching the entry.
Each backlog queue has a queue head counter which is incremented
on dequeue, and so a queue tail counter is computed as queue head
count + queue length. When a packet is enqueued on a backlog queue,
the current value of the queue tail counter is saved in the hash
entry of the rps_dev_flow_table.
And now the trick: when selecting the CPU for RPS (get_rps_cpu)
the rps_sock_flow table and the rps_dev_flow table for the RX queue
are consulted. When the desired CPU for the flow (found in the
rps_sock_flow table) does not match the current CPU (found in the
rps_dev_flow table), the current CPU is changed to the desired CPU
if one of the following is true:
- The current CPU is unset (equal to RPS_NO_CPU)
- Current CPU is offline
- The current CPU's queue head counter >= queue tail counter in the
rps_dev_flow table. This checks if the queue tail has advanced
beyond the last packet that was enqueued using this table entry.
This guarantees that all packets queued using this entry have been
dequeued, thus preserving in order delivery.
Making each queue have its own rps_dev_flow table has two advantages:
1) the tail queue counters will be written on each receive, so
keeping the table local to interrupting CPU s good for locality. 2)
this allows lockless access to the table-- the CPU number and queue
tail counter need to be accessed together under mutual exclusion
from netif_receive_skb, we assume that this is only called from
device napi_poll which is non-reentrant.
This patch implements RFS for TCP and connected UDP sockets.
It should be usable for other flow oriented protocols.
There are two configuration parameters for RFS. The
"rps_flow_entries" kernel init parameter sets the number of
entries in the rps_sock_flow_table, the per rxqueue sysfs entry
"rps_flow_cnt" contains the number of entries in the rps_dev_flow
table for the rxqueue. Both are rounded to power of two.
The obvious benefit of RFS (over just RPS) is that it achieves
CPU locality between the receive processing for a flow and the
applications processing; this can result in increased performance
(higher pps, lower latency).
The benefits of RFS are dependent on cache hierarchy, application
load, and other factors. On simple benchmarks, we don't necessarily
see improvement and sometimes see degradation. However, for more
complex benchmarks and for applications where cache pressure is
much higher this technique seems to perform very well.
Below are some benchmark results which show the potential benfit of
this patch. The netperf test has 500 instances of netperf TCP_RR
test with 1 byte req. and resp. The RPC test is an request/response
test similar in structure to netperf RR test ith 100 threads on
each host, but does more work in userspace that netperf.
e1000e on 8 core Intel
No RFS or RPS 104K tps at 30% CPU
No RFS (best RPS config): 290K tps at 63% CPU
RFS 303K tps at 61% CPU
RPC test tps CPU% 50/90/99% usec latency Latency StdDev
No RFS/RPS 103K 48% 757/900/3185 4472.35
RPS only: 174K 73% 415/993/2468 491.66
RFS 223K 73% 379/651/1382 315.61
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As Herbert Xu said: we should be able to simply replace ipfragok
with skb->local_df. commit f88037(sctp: Drop ipfargok in sctp_xmit function)
has droped ipfragok and set local_df value properly.
The patch kills the ipfragok parameter of .queue_xmit().
Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Paris got following trace with a linux-next kernel
[ 14.203970] BUG: using smp_processor_id() in preemptible [00000000]
code: avahi-daemon/2093
[ 14.204025] caller is netif_rx+0xfa/0x110
[ 14.204035] Call Trace:
[ 14.204064] [<ffffffff81278fe5>] debug_smp_processor_id+0x105/0x110
[ 14.204070] [<ffffffff8142163a>] netif_rx+0xfa/0x110
[ 14.204090] [<ffffffff8145b631>] ip_dev_loopback_xmit+0x71/0xa0
[ 14.204095] [<ffffffff8145b892>] ip_mc_output+0x192/0x2c0
[ 14.204099] [<ffffffff8145d610>] ip_local_out+0x20/0x30
[ 14.204105] [<ffffffff8145d8ad>] ip_push_pending_frames+0x28d/0x3d0
[ 14.204119] [<ffffffff8147f1cc>] udp_push_pending_frames+0x14c/0x400
[ 14.204125] [<ffffffff814803fc>] udp_sendmsg+0x39c/0x790
[ 14.204137] [<ffffffff814891d5>] inet_sendmsg+0x45/0x80
[ 14.204149] [<ffffffff8140af91>] sock_sendmsg+0xf1/0x110
[ 14.204189] [<ffffffff8140dc6c>] sys_sendmsg+0x20c/0x380
[ 14.204233] [<ffffffff8100ad82>] system_call_fastpath+0x16/0x1b
While current linux-2.6 kernel doesnt emit this warning, bug is latent
and might cause unexpected failures.
ip_dev_loopback_xmit() runs in process context, preemption enabled, so
must call netif_rx_ni() instead of netif_rx(), to make sure that we
process pending software interrupt.
Same change for ip6_dev_loopback_xmit()
Reported-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix an oversight in ipmr_destroy_unres() - the net pointer is
unconditionally initialized to NULL, resulting in a NULL pointer
dereference later on.
Fix by adding a net pointer to struct mr_table and using it in
ipmr_destroy_unres().
Signed-off-by: Patrick McHardy <kaber@trash.net>
The patch to convert struct mfc_cache to list_heads (ipv4: ipmr: convert
struct mfc_cache to struct list_head) introduced a bug when adding new
cache entries that don't match any unresolved entries.
The unres queue is searched for a matching entry, which is then resolved.
When no matching entry is present, the iterator points to the head of the
list, but is treated as a matching entry. Use a seperate variable to
indicate that a matching entry was found.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Followup of commit 634a4b20
Allow tnode_get_child_rcu() to be called either under rcu_read_lock()
protection or with RTNL held.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds support for multiple independant multicast routing instances,
named "tables".
Userspace multicast routing daemons can bind to a specific table instance by
issuing a setsockopt call using a new option MRT_TABLE. The table number is
stored in the raw socket data and affects all following ipmr setsockopt(),
getsockopt() and ioctl() calls. By default, a single table (RT_TABLE_DEFAULT)
is created with a default routing rule pointing to it. Newly created pimreg
devices have the table number appended ("pimregX"), with the exception of
devices created in the default table, which are named just "pimreg" for
compatibility reasons.
Packets are directed to a specific table instance using routing rules,
similar to how regular routing rules work. Currently iif, oif and mark
are supported as keys, source and destination addresses could be supported
additionally.
Example usage:
- bind pimd/xorp/... to a specific table:
uint32_t table = 123;
setsockopt(fd, IPPROTO_IP, MRT_TABLE, &table, sizeof(table));
- create routing rules directing packets to the new table:
# ip mrule add iif eth0 lookup 123
# ip mrule add oif eth0 lookup 123
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that cache entries in unres_queue don't need to be distinguished by their
network namespace pointer anymore, we can remove it from struct mfc_cache
add pass the namespace as function argument to the functions that need it.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The unres_queue is currently shared between all namespaces. Following patches
will additionally allow to create multiple multicast routing tables in each
namespace. Having a single shared queue for all these users seems to excessive,
move the queue and the cleanup timer to the per-namespace data to unshare it.
As a side-effect, this fixes a bug in the seq file iteration functions: the
first entry returned is always from the current namespace, entries returned
after that may belong to any namespace.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Decouple the address family values used for fib_rules from the real
address families in socket.h. This allows to use fib_rules for
code that is not a real address family without increasing AF_MAX/NPROTO.
Values up to 127 are reserved for real address families and map directly
to the corresponding AF value, values starting from 128 are for other
uses. rtnetlink is changed to invoke the AF_UNSPEC dumpit/doit handlers
for these families.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
All fib_rules implementations need to set the family in their ->fill()
functions. Since the value is available to the generic fib_nl_fill_rule()
function, set it there.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Both functions are equivalent, consolidate them since a following patch
needs a third implementation for multicast routing.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
With latest CONFIG_PROVE_RCU stuff, I felt more comfortable to make this
work.
sk->sk_dst_cache is currently protected by a rwlock (sk_dst_lock)
This rwlock is readlocked for a very small amount of time, and dst
entries are already freed after RCU grace period. This calls for RCU
again :)
This patch converts sk_dst_lock to a spinlock, and use RCU for readers.
__sk_dst_get() is supposed to be called with rcu_read_lock() or if
socket locked by user, so use appropriate rcu_dereference_check()
condition (rcu_read_lock_held() || sock_owned_by_user(sk))
This patch avoids two atomic ops per tx packet on UDP connected sockets,
for example, and permits sk_dst_lock to be much less dirtied.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Back in commit 04a0551c87
("loopback: Drop obsolete ip_summed setting") we stopped
setting CHECKSUM_UNNECESSARY in the loopback xmit.
This is because such a setting was a lie since it implies that the
checksum field of the packet is properly filled in.
Instead what happens normally is that CHECKSUM_PARTIAL is set and
skb->csum is calculated as needed.
But this was only happening for TCP data packets (via the
skb->ip_summed assignment done in tcp_sendmsg()). It doesn't
happen for non-data packets like ACKs etc.
Fix this by setting skb->ip_summed in the common non-data packet
constructor. It already is setting skb->csum to zero.
But this reminds us that we still have things like ip_output.c's
ip_dev_loopback_xmit() which sets skb->ip_summed to the value
CHECKSUM_UNNECESSARY, which Herbert's patch teaches us is not
valid. So we'll have to address that at some point too.
Signed-off-by: David S. Miller <davem@davemloft.net>
inet: Remove unused send_check length argument
This patch removes the unused length argument from the send_check
function in struct inet_connection_sock_af_ops.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Yinghai <yinghai.lu@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp: Handle CHECKSUM_PARTIAL for SYNACK packets for IPv4
This patch moves the common code between tcp_v4_send_check and
tcp_v4_gso_send_check into a new function __tcp_v4_send_check.
It then uses the new function in tcp_v4_send_synack so that it
handles CHECKSUM_PARTIAL properly.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Yinghai <yinghai.lu@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 2626419ad5.
It causes regressions for people with IGB cards. Connection
requests don't complete etc. The true cause of the issue is
still not known, but we should sort this out in net-next-2.6
not net-2.6
Signed-off-by: David S. Miller <davem@davemloft.net>
Back in commit 04a0551c87
("loopback: Drop obsolete ip_summed setting") we stopped
setting CHECKSUM_UNNECESSARY in the loopback xmit.
This is because such a setting was a lie since it implies that the
checksum field of the packet is properly filled in.
Instead what happens normally is that CHECKSUM_PARTIAL is set and
skb->csum is calculated as needed.
But this was only happening for TCP data packets (via the
skb->ip_summed assignment done in tcp_sendmsg()). It doesn't
happen for non-data packets like ACKs etc.
Fix this by setting skb->ip_summed in the common non-data packet
constructor. It already is setting skb->csum to zero.
But this reminds us that we still have things like ip_output.c's
ip_dev_loopback_xmit() which sets skb->ip_summed to the value
CHECKSUM_UNNECESSARY, which Herbert's patch teaches us is not
valid. So we'll have to address that at some point too.
Signed-off-by: David S. Miller <davem@davemloft.net>
Commits 5051ebd275 and
5051ebd275 ("ipv[46]: udp: optimize unicast RX
path") broke some programs.
After upgrading a L2TP server to 2.6.33 it started to fail, tunnels going up an
down, after the 10th tunnel came up. My modified rp-l2tp uses a global
unconnected socket bound to (INADDR_ANY, 1701) and one connected socket per
tunnel after parameter negotiation.
After ten sockets were open and due to mixed parameters to
udp[46]_lib_lookup2() kernel started to drop packets.
Signed-off-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
__xfrm_lookup() is called for each packet transmitted out of
system. The xfrm_find_bundle() does a linear search which can
kill system performance depending on how many bundles are
required per policy.
This modifies __xfrm_lookup() to store bundles directly in
the flow cache. If we did not get a hit, we just create a new
bundle instead of doing slow search. This means that we can now
get multiple xfrm_dst's for same flow (on per-cpu basis).
Signed-off-by: Timo Teras <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (37 commits)
smc91c92_cs: fix the problem of "Unable to find hardware address"
r8169: clean up my printk uglyness
net: Hook up cxgb4 to Kconfig and Makefile
cxgb4: Add main driver file and driver Makefile
cxgb4: Add remaining driver headers and L2T management
cxgb4: Add packet queues and packet DMA code
cxgb4: Add HW and FW support code
cxgb4: Add register, message, and FW definitions
netlabel: Fix several rcu_dereference() calls used without RCU read locks
bonding: fix potential deadlock in bond_uninit()
net: check the length of the socket address passed to connect(2)
stmmac: add documentation for the driver.
stmmac: fix kconfig for crc32 build error
be2net: fix bug in vlan rx path for big endian architecture
be2net: fix flashing on big endian architectures
be2net: fix a bug in flashing the redboot section
bonding: bond_xmit_roundrobin() fix
drivers/net: Add missing unlock
net: gianfar - align BD ring size console messages
net: gianfar - initialize per-queue statistics
...
When ip_append() fails because of socket limit or memory shortage,
increment ICMP_MIB_OUTERRORS counter, so that "netstat -s" can report
these errors.
LANG=C netstat -s | grep "ICMP messages failed"
0 ICMP messages failed
For IPV6, implement ICMP6_MIB_OUTERRORS counter as well.
# grep Icmp6OutErrors /proc/net/dev_snmp6/*
/proc/net/dev_snmp6/eth0:Icmp6OutErrors 0
/proc/net/dev_snmp6/lo:Icmp6OutErrors 0
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Converts the list and the core manipulating with it to be the same as uc_list.
+uses two functions for adding/removing mc address (normal and "global"
variant) instead of a function parameter.
+removes dev_mcast.c completely.
+exposes netdev_hw_addr_list_* macros along with __hw_addr_* functions for
manipulation with lists on a sandbox (used in bonding and 80211 drivers)
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The check if error signaling is wanted (inet->recverr != 0) is done by
the caller: raw.c:raw_err() and udp.c:__udp4_lib_err(), so there is no
need to check this condition again.
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
check the length of the socket address passed to connect(2).
Check the length of the socket address passed to connect(2). If the
length is invalid, -EINVAL will be returned.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
----
net/bluetooth/l2cap.c | 3 ++-
net/bluetooth/rfcomm/sock.c | 3 ++-
net/bluetooth/sco.c | 3 ++-
net/can/bcm.c | 3 +++
net/ieee802154/af_ieee802154.c | 3 +++
net/ipv4/af_inet.c | 5 +++++
net/netlink/af_netlink.c | 3 +++
7 files changed, 20 insertions(+), 3 deletions(-)
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_read_sock() can have a eat skbs without immediately advancing copied_seq.
This can cause a panic in tcp_collapse() if it is called as a result
of the recv_actor dropping the socket lock.
A userspace program that splices data from a socket to either another
socket or to a file can trigger this bug.
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
