We tried very hard to remove all possible dev_hold()/dev_put() pairs in
network stack, using RCU conversions.

There is still an unavoidable device refcount change for every dst we
create/destroy, and this can slow down some workloads (routers or some
app servers, mmap af_packet)

We can switch to a percpu refcount implementation, now dynamic per_cpu
infrastructure is mature. On a 64 cpus machine, this consumes 256 bytes
per device.

On x86, dev_hold(dev) code :

before
        lock    incl 0x280(%ebx)
after:
        movl    0x260(%ebx),%eax
        incl    fs:(%eax)

Stress bench :

(Sending 160.000.000 UDP frames,
IP route cache disabled, dual E5540 @2.53GHz,
32bit kernel, FIB_TRIE)

Before:

real    1m1.662s
user    0m14.373s
sys     12m55.960s

After:

real    0m51.179s
user    0m15.329s
sys     10m15.942s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This  omits the redundant "DCCP:" in warning messages, since DCCP_WARN() already
echoes the function name, avoiding messages like

   kernel: [10988.766503] dccp_close: DCCP: ABORT -- 209 bytes unread
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

This schedules an Ack when receiving a timestamp, exploiting the
existing inet_csk_schedule_ack() function, saving one case in the
`dccp_ack_pending()' function.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

This patch generalises the task of determining data loss from RFC 4340, 7.7.1.

Let S_A, S_B be sequence numbers such that S_B is "after" S_A, and let
N_B be the NDP count of packet S_B. Then, using modulo-2^48 arithmetic,
 D = S_B - S_A - 1  is an upper bound of the number of lost data packets,
 D - N_B            is an approximation of the number of lost data packets
                    (there are cases where this is not exact).

The patch implements this as
 dccp_loss_count(S_A, S_B, N_B) := max(S_B - S_A - 1 - N_B, 0)
Signed-off-by: Ivo Calado <ivocalado@embedded.ufcg.edu.br>
Signed-off-by: Erivaldo Xavier <desadoc@gmail.com>
Signed-off-by: Leandro Sales <leandroal@gmail.com>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

This removes the argument `more' from ccid_hc_tx_packet_sent, since it was
nowhere used in the entire code.

(Btw, this argument was not even used in the original KAME code where the
 function initially came from; compare the variable moreToSend in the
 freebsd61-dccp-kame-28.08.2006.patch kept by Emmanuel Lochin.)
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

After moving the assignment of GAR/ISS from dccp_connect_init() to
dccp_transmit_skb(), the former function becomes very small, so that
a merger with dccp_connect() suggests itself.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

This fixes a problem and a potential loophole with regard to seqno/ackno
validity: currently the initial adjustments to AWL/SWL are only performed
once at the begin of the connection, during the handshake.

Since the Sequence Window feature is always greater than Wmin=32 (7.5.2),
it is however necessary to perform these adjustments at least for the first
W/W' (variables as per 7.5.1) packets in the lifetime of a connection.

This requirement is complicated by the fact that W/W' can change at any time
during the lifetime of a connection.

Therefore it is better to perform that safety check each time SWL/AWL are
updated, as implemented by the patch.

A second problem solved by this patch is that the remote/local Sequence Window
feature values (which set the bounds for AWL/SWL/SWH) are undefined until the
feature negotiation has completed.

During the initial handshake we have more stringent sequence number protection;
the changes added by this patch effect that {A,S}W{L,H} are within the correct
bounds at the instant that feature negotiation completes (since the SeqWin
feature activation handlers call dccp_update_gsr/gss()).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

To prevent unnecessary error message.  pci_save_state() is also moved to
the end of ->probe() so that all PCI config, including AER state, will be
saved.

Update version to 2.0.18.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Reviewed-by: Benjamin Li <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

- Improved flow control and simplified interface
- Use hardware RSS indirection table instead of the slower firmware-
  based table
- Lower latency interrupt on 5709
Signed-off-by: Michael Chan <mchan@broadcom.com>
Reviewed-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Le mardi 12 octobre 2010 à 00:02 +0200, Eric Dumazet a écrit :
> Here is the followup patch.
>
> Thanks !
>

Oops, this was an old version, the up2date ones also took care of "used"
field.

I guess its time for a sleep, sorry again.

[PATCH net-next V2] neigh: reorder struct neighbour fields

(refcnt) and (ha_lock, ha, used, dev, output, ops, primary_key) should
be placed on a separate cache lines.

refcnt can be often written, while other fields are mostly read.

This gave me good result on stress test :

before:

real    0m45.570s
user    0m15.525s
sys     9m56.669s

After:

real    0m41.841s
user    0m15.261s
sys     8m45.949s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

struct dst_ops tracks number of allocated dst in an atomic_t field,
subject to high cache line contention in stress workload.

Switch to a percpu_counter, to reduce number of time we need to dirty a
central location. Place it on a separate cache line to avoid dirtying
read only fields.

Stress test :

(Sending 160.000.000 UDP frames,
IP route cache disabled, dual E5540 @2.53GHz,
32bit kernel, FIB_TRIE, SLUB/NUMA)

Before:

real    0m51.179s
user    0m15.329s
sys     10m15.942s

After:

real	0m45.570s
user	0m15.525s
sys	9m56.669s

With a small reordering of struct neighbour fields, subject of a
following patch, (to separate refcnt from other read mostly fields)

real	0m41.841s
user	0m15.261s
sys	8m45.949s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add a seqlock in struct neighbour to protect neigh->ha[], and avoid
dirtying neighbour in stress situation (many different flows / dsts)

Dirtying takes place because of read_lock(&n->lock) and n->used writes.

Switching to a seqlock, and writing n->used only on jiffies changes
permits less dirtying.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:
	net/core/ethtool.c

Several other ethtool functions leave heap uncleared (potentially) by
drivers. Some interfaces appear safe (eeprom, etc), in that the sizes
are well controlled. In some situations (e.g. unchecked error conditions),
the heap will remain unchanged in areas before copying back to userspace.
Note that these are less of an issue since these all require CAP_NET_ADMIN.

Cc: stable@kernel.org
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stanse found that pch_gbe_xmit_frame uses skb after it is freed. Fix
that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Masayuki Ohtake <masa-korg@dsn.okisemi.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stanse found that i2400m_rx frees skb, but still uses skb->len even
though it has skb_len defined. So use skb_len properly in the code.

And also define it unsinged int rather than size_t to solve
compilation warnings.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Cc: linux-wimax@intel.com
Acked-by: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stanse found that ia_init_one locks a spinlock and inside of that it
calls ia_start which calls:
* request_irq
* tx_init which does kmalloc(GFP_KERNEL)

Both of them can thus sleep and result in a deadlock. I don't see a
reason to have a per-device spinlock there which is used only there
and inited right before the lock location. So remove it completely.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Chas Williams <chas@cmf.nrl.navy.mil>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stanse found that mpc_push frees skb and then it dereferences it. It
is a typo, new_skb should be dereferenced there.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stanse found we do in console_show:
  kfree_skb(skb);
  return skb->len;
which is not good. Fix that by remembering the len and use it in the
function instead.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Chas Williams <chas@cmf.nrl.navy.mil>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When a new dst is used to send a frame, neigh_resolve_output() tries to
associate an struct hh_cache to this dst, calling neigh_hh_init() with
the neigh rwlock write locked.

Most of the time, hh_cache is already known and linked into neighbour,
so we find it and increment its refcount.

This patch changes the logic so that we call neigh_hh_init() with
neighbour lock read locked only, so that fast path can be run in
parallel by concurrent cpus.

This brings part of the speedup we got with commit c7d4426a
(introduce DST_NOCACHE flag) for non cached dsts, even for cached ones,
removing one of the contention point that routers hit on multiqueue
enabled machines.

Further improvements would need to use a seqlock instead of an rwlock to
protect neigh->ha[], to not dirty neigh too often and remove two atomic
ops.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

with hardware slow in negotiation, the system did freeze
while trying to mount root on nfs at boot time.

the link state has not been initialised so network stack
tried to start transmission right away. this caused instant
retries, as the driver solely stated business upon link down,
rendering the system unusable.

notify carrier off initially to prevent transmission until
phylib will report link up.
Signed-off-by: Oskar Schirmer <oskar@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

While parsing the GetValuebyClass command frame, we could potentially write
passed the skb->data pointer.

Cc: stable@kernel.org
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>

Cc: stable@kernel.org
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>

Test whether index exceeds fw->size before reading the element
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>

The code intends to lock the irnet_socket, so adding a mutex to it allows
for a complet BKL removal.
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>

Most of the times, lock_kernel() was pointless or could simply be replaced
by lock_sock().
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>

sundance get_stats() should not be run concurrently, add a lock to avoid
potential losses.

Note: Remove unused rx_lock field
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Simplify: ((a && !b) || (!a && b)) => (a != b)
Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Simplify: ((a && b) || (!a && !b)) => (a == b)
Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Acked-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use DMA API as PCI equivalents will be deprecated. This change also
allow to allocate with GFP_KERNEL where possible.
Tested-by: Neal Becker <ndbecker2@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We have fedora bug report where driver fail to initialize after
suspend/resume because of memory allocation errors:
https://bugzilla.redhat.com/show_bug.cgi?id=629158

To fix use GFP_KERNEL allocation where possible.
Tested-by: Neal Becker <ndbecker2@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The rx->count reference is used to track reference counts to the
number of rx-queue kobjects created for the device.  This patch
eliminates initialization of the counter in netif_alloc_rx_queues
and instead increments the counter each time a kobject is created.
This is now symmetric with the decrement that is done when an object is
released.
Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There are a bunch of issues that need to be fixed, including:
 - GFP_KERNEL allocations from atomic context
   (and GFP_ATOMIC in process context),
 - abuse of the setsockopt() call convention,
 - unprotected/unlocked static variables...

IMHO, we will need to alter the userspace ABI when we fix it. So mark
the configuration option as EXPERIMENTAL for the time being (or should
it be BROKEN instead?).
Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The current code works like this:

  int garbage, status;
  socklen_t len = sizeof(status);

  /* enable pipe */
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &garbage, sizeof(garbage));
  /* disable pipe */
  setsockopt(fd, SOL_PNPIPE, PNPIPE_DISABLE, &garbage, sizeof(garbage));
  /* get status */
  getsockopt(fd, SOL_PNPIPE, PNPIPE_INQ, &status, &len);

...which does not follow the usual socket option pattern. This patch
merges all three "options" into a single gettable&settable option,
before Linux 2.6.37 gets out:

  int status;
  socklen_t len = sizeof(status);

  /* enable pipe */
  status = 1;
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, sizeof(status));
  /* disable pipe */
  status = 0;
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, sizeof(status));
  /* get status */
  getsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, &len);

This also fixes the error code from EFAULT to ENOTCONN.
Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Cc: Kumar Sanghvi <kumar.sanghvi@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

As it currently is, the new code path is not compatible with existing
Nokia modems. This would break existing userspace for Nokia modem, such
as the existing oFono ISI driver.
Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>