Not sure what I was thinking, but doing anything after
releasing a refcount is suicidal or/and embarrassing.

By the time we set skb->fclone to SKB_FCLONE_FREE, another cpu
could have released last reference and freed whole skb.

We potentially corrupt memory or trap if CONFIG_DEBUG_PAGEALLOC is set.

Reported-by: Chris Mason <clm@fb.com>
Fixes: ce1a4ea3f1258 ("net: avoid one atomic operation in skb_clone()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

if ->encapsulation is set we have to use inner_tcp_hdrlen and add the
size of the inner network headers too.

This is 'mostly harmless'; tbf might send skb that is slightly over
quota or drop skb even if it would have fit.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull percpu consistent-ops changes from Tejun Heo:
 "Way back, before the current percpu allocator was implemented, static
  and dynamic percpu memory areas were allocated and handled separately
  and had their own accessors.  The distinction has been gone for many
  years now; however, the now duplicate two sets of accessors remained
  with the pointer based ones - this_cpu_*() - evolving various other
  operations over time.  During the process, we also accumulated other
  inconsistent operations.

  This pull request contains Christoph's patches to clean up the
  duplicate accessor situation.  __get_cpu_var() uses are replaced with
  with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().

  Unfortunately, the former sometimes is tricky thanks to C being a bit
  messy with the distinction between lvalues and pointers, which led to
  a rather ugly solution for cpumask_var_t involving the introduction of
  this_cpu_cpumask_var_ptr().

  This converts most of the uses but not all.  Christoph will follow up
  with the remaining conversions in this merge window and hopefully
  remove the obsolete accessors"

* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
  irqchip: Properly fetch the per cpu offset
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
  ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
  Revert "powerpc: Replace __get_cpu_var uses"
  percpu: Remove __this_cpu_ptr
  clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
  sparc: Replace __get_cpu_var uses
  avr32: Replace __get_cpu_var with __this_cpu_write
  blackfin: Replace __get_cpu_var uses
  tile: Use this_cpu_ptr() for hardware counters
  tile: Replace __get_cpu_var uses
  powerpc: Replace __get_cpu_var uses
  alpha: Replace __get_cpu_var
  ia64: Replace __get_cpu_var uses
  s390: cio driver &__get_cpu_var replacements
  s390: Replace __get_cpu_var uses
  mips: Replace __get_cpu_var uses
  MIPS: Replace __get_cpu_var uses in FPU emulator.
  arm: Replace __this_cpu_ptr with raw_cpu_ptr
  ...

This is illegal to use atomic_set(&page->_count, ...) even if we 'own'
the page. Other entities in the kernel need to use get_page_unless_zero()
to get a reference to the page before testing page properties, so we could
loose a refcount increment.

The only case it is valid is when page->_count is 0

Fixes: 540eb7bf0bbed ("net: Update alloc frag to reduce get/put page usage and recycle pages")
Signed-off-by: Eric Dumaze <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch fix following warning.
Warning(.//net/core/skbuff.c:4142): No description found for parameter 'header_len'
Warning(.//net/core/skbuff.c:4142): No description found for parameter 'data_len'
Warning(.//net/core/skbuff.c:4142): No description found for parameter 'max_page_order'
Warning(.//net/core/skbuff.c:4142): No description found for parameter 'errcode'
Warning(.//net/core/skbuff.c:4142): No description found for parameter 'gfp_mask'

Acutually the descriptions exist, but missing "@" in front.

This problem start to happen when following commit was merged
into Linus's tree during 3.18-rc1 merge period.
commit 2e4e44107176d552f8bb1bb76053e850e3809841
net: add alloc_skb_with_frags() helper

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Its unfortunate we have to walk again skb list to find the tail
after segmentation, even if data is probably hot in cpu caches.

skb_segment() can store the tail of the list into segs->prev,
and validate_xmit_skb_list() can immediately get the tail.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

The following patchset contains another batch with Netfilter/IPVS updates
for net-next, they are:

1) Add abstracted ICMP codes to the nf_tables reject expression. We
   introduce four reasons to reject using ICMP that overlap in IPv4
   and IPv6 from the semantic point of view. This should simplify the
   maintainance of dual stack rule-sets through the inet table.

2) Move nf_send_reset() functions from header files to per-family
   nf_reject modules, suggested by Patrick McHardy.

3) We have to use IS_ENABLED(CONFIG_BRIDGE_NETFILTER) everywhere in the
   code now that br_netfilter can be modularized. Convert remaining spots
   in the network stack code.

4) Use rcu_barrier() in the nf_tables module removal path to ensure that
   we don't leave object that are still pending to be released via
   call_rcu (that may likely result in a crash).

5) Remove incomplete arch 32/64 compat from nft_compat. The original (bad)
   idea was to probe the word size based on the xtables match/target info
   size, but this assumption is wrong when you have to dump the information
   back to userspace.

6) Allow to filter from prerouting and postrouting in the nf_tables bridge.
   In order to emulate the ebtables NAT chains (which are actually simple
   filter chains with no special semantics), we have support filtering from
   this hooks too.

7) Add explicit module dependency between xt_physdev and br_netfilter.
   This provides a way to detect if the user needs br_netfilter from
   the configuration path. This should reduce the breakage of the
   br_netfilter modularization.

8) Cleanup coding style in ip_vs.h, from Simon Horman.

9) Fix crash in the recently added nf_tables masq expression. We have
   to register/unregister the notifiers to clean up the conntrack table
   entries from the module init/exit path, not from the rule addition /
   deletion path. From Arturo Borrero.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

SKB_FCLONE_UNAVAILABLE has overloaded meaning depending on type of skb.
1: If skb is allocated from head_cache, it indicates fclone is not available.
2: If skb is a companion fclone skb (allocated from fclone_cache), it indicates
it is available to be used.

To avoid confusion for case 2 above, this patch  replaces
SKB_FCLONE_UNAVAILABLE with SKB_FCLONE_FREE where appropriate. For fclone
companion skbs, this indicates it is free for use.

SKB_FCLONE_UNAVAILABLE will now simply indicate skb is from head_cache and
cannot / will not have a companion fclone.

Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

skb_gro_receive() is only called from tcp_gro_receive() which is
not in a module.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:
	drivers/net/usb/r8152.c
	net/netfilter/nfnetlink.c

Both r8152 and nfnetlink conflicts were simple overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>