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  1. 01 5月, 2017 1 次提交
  3. 18 4月, 2017 1 次提交
  5. 14 4月, 2017 1 次提交
  7. 02 3月, 2017 1 次提交
  9. 15 12月, 2016 1 次提交
  11. 04 12月, 2016 3 次提交
    • A
      netns: fix net_generic() "id - 1" bloat · 6af2d5ff
      由 Alexey Dobriyan 提交于 
      net_generic() function is both a) inline and b) used ~600 times.

It has the following code inside

		...
	ptr = ng->ptr[id - 1];
		...

"id" is never compile time constant so compiler is forced to subtract 1.
And those decrements or LEA [r32 - 1] instructions add up.

We also start id'ing from 1 to catch bugs where pernet sybsystem id
is not initialized and 0. This is quite pointless idea (nothing will
work or immediate interference with first registered subsystem) in
general but it hints what needs to be done for code size reduction.

Namely, overlaying allocation of pointer array and fixed part of
structure in the beginning and using usual base-0 addressing.

Ids are just cookies, their exact values do not matter, so lets start
with 3 on x86_64.

Code size savings (oh boy): -4.2 KB

As usual, ignore the initial compiler stupidity part of the table.

	add/remove: 0/0 grow/shrink: 12/670 up/down: 89/-4297 (-4208)
	function                                     old     new   delta
	tipc_nametbl_insert_publ                    1250    1270     +20
	nlmclnt_lookup_host                          686     703     +17
	nfsd4_encode_fattr                          5930    5941     +11
	nfs_get_client                              1050    1061     +11
	register_pernet_operations                   333     342      +9
	tcf_mirred_init                              843     849      +6
	tcf_bpf_init                                1143    1149      +6
	gss_setup_upcall                             990     994      +4
	idmap_name_to_id                             432     434      +2
	ops_init                                     274     275      +1
	nfsd_inject_forget_client                    259     260      +1
	nfs4_alloc_client                            612     613      +1
	tunnel_key_walker                            164     163      -1

		...

	tipc_bcbase_select_primary                   392     360     -32
	mac80211_hwsim_new_radio                    2808    2767     -41
	ipip6_tunnel_ioctl                          2228    2186     -42
	tipc_bcast_rcv                               715     672     -43
	tipc_link_build_proto_msg                   1140    1089     -51
	nfsd4_lock                                  3851    3796     -55
	tipc_mon_rcv                                1012     956     -56
	Total: Before=156643951, After=156639743, chg -0.00%
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6af2d5ff
    • A
      netns: add dummy struct inside "struct net_generic" · 9bfc7b99
      由 Alexey Dobriyan 提交于 
      This is precursor to fixing "[id - 1]" bloat inside net_generic().

Name "s" is chosen to complement name "u" often used for dummy unions.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      9bfc7b99
    • A
      netns: publish net_generic correctly · 1a9a0592
      由 Alexey Dobriyan 提交于 
      Publishing net_generic pointer is done with silly mistake: new array is
published BEFORE setting freshly acquired pernet subsystem pointer.

	memcpy
	rcu_assign_pointer
	kfree_rcu
	ng->ptr[id - 1] = data;

This bug was introduced with commit dec827d1
("[NETNS]: The generic per-net pointers.") in the glorious days of
chopping networking stack into containers proper 8.5 years ago (whee...)

How it didn't trigger for so long?
Well, you need quite specific set of conditions:

*) race window opens once per pernet subsystem addition
   (read: modprobe or boot)

*) not every pernet subsystem is eligible (need ->id and ->size)

*) not every pernet subsystem is vulnerable (need incorrect or absense
   of ordering of register_pernet_sybsys() and actually using net_generic())

*) to hide the bug even more, default is to preallocate 13 pointers which
   is actually quite a lot. You need IPv6, netfilter, bridging etc together
   loaded to trigger reallocation in the first place. Trimmed down
   config are OK.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1a9a0592
  13. 18 11月, 2016 2 次提交
    • A
      netns: make struct pernet_operations::id unsigned int · c7d03a00
      由 Alexey Dobriyan 提交于 
      Make struct pernet_operations::id unsigned.

There are 2 reasons to do so:

1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.

2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.

"int" being used as an array index needs to be sign-extended
to 64-bit before being used.

	void f(long *p, int i)
	{
		g(p[i]);
	}

  roughly translates to

	movsx	rsi, esi
	mov	rdi, [rsi+...]
	call 	g

MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.

Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:

	static inline void *net_generic(const struct net *net, int id)
	{
		...
		ptr = ng->ptr[id - 1];
		...
	}

And this function is used a lot, so those sign extensions add up.

Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)

Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]

However, overall balance is in negative direction:

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
	function                                     old     new   delta
	nfsd4_lock                                  3886    3959     +73
	tipc_link_build_proto_msg                   1096    1140     +44
	mac80211_hwsim_new_radio                    2776    2808     +32
	tipc_mon_rcv                                1032    1058     +26
	svcauth_gss_legacy_init                     1413    1429     +16
	tipc_bcbase_select_primary                   379     392     +13
	nfsd4_exchange_id                           1247    1260     +13
	nfsd4_setclientid_confirm                    782     793     +11
		...
	put_client_renew_locked                      494     480     -14
	ip_set_sockfn_get                            730     716     -14
	geneve_sock_add                              829     813     -16
	nfsd4_sequence_done                          721     703     -18
	nlmclnt_lookup_host                          708     686     -22
	nfsd4_lockt                                 1085    1063     -22
	nfs_get_client                              1077    1050     -27
	tcf_bpf_init                                1106    1076     -30
	nfsd4_encode_fattr                          5997    5930     -67
	Total: Before=154856051, After=154854321, chg -0.00%
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      c7d03a00
    • W
      net: check dead netns for peernet2id_alloc() · cfc44a4d
      由 WANG Cong 提交于 
      Andrei reports we still allocate netns ID from idr after we destroy
it in cleanup_net().

cleanup_net():
  ...
  idr_destroy(&net->netns_ids);
  ...
  list_for_each_entry_reverse(ops, &pernet_list, list)
    ops_exit_list(ops, &net_exit_list);
      -> rollback_registered_many()
        -> rtmsg_ifinfo_build_skb()
         -> rtnl_fill_ifinfo()
           -> peernet2id_alloc()

After that point we should not even access net->netns_ids, we
should check the death of the current netns as early as we can in
peernet2id_alloc().

For net-next we can consider to avoid sending rtmsg totally,
it is a good optimization for netns teardown path.

Fixes: 0c7aecd4 ("netns: add rtnl cmd to add and get peer netns ids")
Reported-by: NAndrei Vagin <avagin@gmail.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NAndrei Vagin <avagin@openvz.org>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      cfc44a4d
  15. 24 10月, 2016 1 次提交
  17. 23 10月, 2016 1 次提交
  19. 24 9月, 2016 1 次提交
    • A
      netns: move {inc,dec}_net_namespaces into #ifdef · 2ed6afde
      由 Arnd Bergmann 提交于 
      With the newly enforced limit on the number of namespaces,
we get a build warning if CONFIG_NETNS is disabled:

net/core/net_namespace.c:273:13: error: 'dec_net_namespaces' defined but not used [-Werror=unused-function]
net/core/net_namespace.c:268:24: error: 'inc_net_namespaces' defined but not used [-Werror=unused-function]

This moves the two added functions inside the #ifdef that guards
their callers.

Fixes: 70328660 ("netns: Add a limit on the number of net namespaces")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
      2ed6afde
  21. 23 9月, 2016 2 次提交
  23. 05 9月, 2016 2 次提交
  25. 02 9月, 2016 1 次提交
  27. 15 8月, 2016 1 次提交
    • D
      netns: do not call pernet ops for not yet set up init_net namespace · f8c46cb3
      由 Dmitry Torokhov 提交于 
      When CONFIG_NET_NS is disabled, registering pernet operations causes
init() to be called immediately with init_net as an argument. Unfortunately
this leads to some pernet ops, such as proc_net_ns_init() to be called too
early, when init_net namespace has not been fully initialized. This causes
issues when we want to change pernet ops to use more data from the net
namespace in question, for example reference user namespace that owns our
network namespace.

To fix this we could either play game of musical chairs and rearrange init
order, or we could do the same as when CONFIG_NET_NS is enabled, and
postpone calling pernet ops->init() until namespace is set up properly.

Note that we can not simply undo commit ed160e83 ("[NET]: Cleanup
pernet operation without CONFIG_NET_NS") and use the same implementations
for __register_pernet_operations() and __unregister_pernet_operations(),
because many pernet ops are marked as __net_initdata and will be discarded,
which wreaks havoc on our ops lists. Here we rely on the fact that we only
use lists until init_net is fully initialized, which happens much earlier
than discarding __net_initdata sections.
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f8c46cb3
  29. 09 8月, 2016 1 次提交
  31. 18 5月, 2015 1 次提交
  33. 15 5月, 2015 1 次提交
  35. 13 5月, 2015 1 次提交
  37. 10 5月, 2015 6 次提交
  39. 17 4月, 2015 1 次提交
  41. 08 4月, 2015 3 次提交
  43. 04 4月, 2015 2 次提交
  45. 30 3月, 2015 1 次提交
    • N
      netns: don't clear nsid too early on removal · 4217291e
      由 Nicolas Dichtel 提交于 
      With the current code, ids are removed too early.
Suppose you have an ipip interface that stands in the netns foo and its link
part in the netns bar (so the netns bar has an nsid into the netns foo).
Now, you remove the netns bar:
 - the bar nsid into the netns foo is removed
 - the netns exit method of ipip is called, thus our ipip iface is removed:
   => a netlink message is sent in the netns foo to advertise this deletion
   => this netlink message requests an nsid for bar, thus a new nsid is
      allocated for bar and never removed.

We must remove nsids when we are sure that nobody will refer to netns currently
cleaned.

Fixes: 0c7aecd4 ("netns: add rtnl cmd to add and get peer netns ids")
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4217291e
  47. 13 3月, 2015 1 次提交
  49. 24 1月, 2015 1 次提交
  51. 23 1月, 2015 1 次提交
  53. 20 1月, 2015 1 次提交