linux.git/net/phonet, branch v4.11

net: Work around lockdep limitation in sockets that use sockets

2017-03-10T02:23:27+00:00

Lockdep issues a circular dependency warning when AFS issues an operation
through AF_RXRPC from a context in which the VFS/VM holds the mmap_sem.

The theory lockdep comes up with is as follows:

 (1) If the pagefault handler decides it needs to read pages from AFS, it
     calls AFS with mmap_sem held and AFS begins an AF_RXRPC call, but
     creating a call requires the socket lock:

	mmap_sem must be taken before sk_lock-AF_RXRPC

 (2) afs_open_socket() opens an AF_RXRPC socket and binds it.  rxrpc_bind()
     binds the underlying UDP socket whilst holding its socket lock.
     inet_bind() takes its own socket lock:

	sk_lock-AF_RXRPC must be taken before sk_lock-AF_INET

 (3) Reading from a TCP socket into a userspace buffer might cause a fault
     and thus cause the kernel to take the mmap_sem, but the TCP socket is
     locked whilst doing this:

	sk_lock-AF_INET must be taken before mmap_sem

However, lockdep's theory is wrong in this instance because it deals only
with lock classes and not individual locks.  The AF_INET lock in (2) isn't
really equivalent to the AF_INET lock in (3) as the former deals with a
socket entirely internal to the kernel that never sees userspace.  This is
a limitation in the design of lockdep.

Fix the general case by:

 (1) Double up all the locking keys used in sockets so that one set are
     used if the socket is created by userspace and the other set is used
     if the socket is created by the kernel.

 (2) Store the kern parameter passed to sk_alloc() in a variable in the
     sock struct (sk_kern_sock).  This informs sock_lock_init(),
     sock_init_data() and sk_clone_lock() as to the lock keys to be used.

     Note that the child created by sk_clone_lock() inherits the parent's
     kern setting.

 (3) Add a 'kern' parameter to ->accept() that is analogous to the one
     passed in to ->create() that distinguishes whether kernel_accept() or
     sys_accept4() was the caller and can be passed to sk_alloc().

     Note that a lot of accept functions merely dequeue an already
     allocated socket.  I haven't touched these as the new socket already
     exists before we get the parameter.

     Note also that there are a couple of places where I've made the accepted
     socket unconditionally kernel-based:

	irda_accept()
	rds_rcp_accept_one()
	tcp_accept_from_sock()

     because they follow a sock_create_kern() and accept off of that.

Whilst creating this, I noticed that lustre and ocfs don't create sockets
through sock_create_kern() and thus they aren't marked as for-kernel,
though they appear to be internal.  I wonder if these should do that so
that they use the new set of lock keys.

Signed-off-by: David Howells 
Signed-off-by: David S. Miller

sched/headers: Prepare to move signal wakeup & sigpending methods from into

2017-03-02T07:42:32+00:00

Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

netns: make struct pernet_operations::id unsigned int

2016-11-18T15:59:15+00:00

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: Alexey Dobriyan 
Signed-off-by: David S. Miller

net: fix sleeping for sk_wait_event()

2016-11-14T18:17:21+00:00

Similar to commit 14135f30e33c ("inet: fix sleeping inside inet_wait_for_connect()"),
sk_wait_event() needs to fix too, because release_sock() is blocking,
it changes the process state back to running after sleep, which breaks
the previous prepare_to_wait().

Switch to the new wait API.

Cc: Eric Dumazet 
Cc: Peter Zijlstra 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

net: use core MTU range checking in misc drivers

2016-10-20T18:51:10+00:00

firewire-net:
- set min/max_mtu
- remove fwnet_change_mtu

nes:
- set max_mtu
- clean up nes_netdev_change_mtu

xpnet:
- set min/max_mtu
- remove xpnet_dev_change_mtu

hippi:
- set min/max_mtu
- remove hippi_change_mtu

batman-adv:
- set max_mtu
- remove batadv_interface_change_mtu
- initialization is a little async, not 100% certain that max_mtu is set
  in the optimal place, don't have hardware to test with

rionet:
- set min/max_mtu
- remove rionet_change_mtu

slip:
- set min/max_mtu
- streamline sl_change_mtu

um/net_kern:
- remove pointless ndo_change_mtu

hsi/clients/ssi_protocol:
- use core MTU range checking
- remove now redundant ssip_pn_set_mtu

ipoib:
- set a default max MTU value
- Note: ipoib's actual max MTU can vary, depending on if the device is in
  connected mode or not, so we'll just set the max_mtu value to the max
  possible, and let the ndo_change_mtu function continue to validate any new
  MTU change requests with checks for CM or not. Note that ipoib has no
  min_mtu set, and thus, the network core's mtu > 0 check is the only lower
  bounds here.

mptlan:
- use net core MTU range checking
- remove now redundant mpt_lan_change_mtu

fddi:
- min_mtu = 21, max_mtu = 4470
- remove now redundant fddi_change_mtu (including export)

fjes:
- min_mtu = 8192, max_mtu = 65536
- The max_mtu value is actually one over IP_MAX_MTU here, but the idea is to
  get past the core net MTU range checks so fjes_change_mtu can validate a
  new MTU against what it supports (see fjes_support_mtu in fjes_hw.c)

hsr:
- min_mtu = 0 (calls ether_setup, max_mtu is 1500)

f_phonet:
- min_mtu = 6, max_mtu = 65541

u_ether:
- min_mtu = 14, max_mtu = 15412

phonet/pep-gprs:
- min_mtu = 576, max_mtu = 65530
- remove redundant gprs_set_mtu

CC: netdev@vger.kernel.org
CC: linux-rdma@vger.kernel.org
CC: Stefan Richter 
CC: Faisal Latif 
CC: linux-rdma@vger.kernel.org
CC: Cliff Whickman 
CC: Robin Holt 
CC: Jes Sorensen 
CC: Marek Lindner 
CC: Simon Wunderlich 
CC: Antonio Quartulli 
CC: Sathya Prakash 
CC: Chaitra P B 
CC: Suganath Prabu Subramani 
CC: MPT-FusionLinux.pdl@broadcom.com
CC: Sebastian Reichel 
CC: Felipe Balbi 
CC: Arvid Brodin 
CC: Remi Denis-Courmont 
Signed-off-by: Jarod Wilson 
Signed-off-by: David S. Miller

sock: struct proto hash function may error

2016-02-11T08:54:14+00:00

In order to support fast reuseport lookups in TCP, the hash function
defined in struct proto must be capable of returning an error code.
This patch changes the function signature of all related hash functions
to return an integer and handles or propagates this return value at
all call sites.

Signed-off-by: Craig Gallek 
Signed-off-by: David S. Miller

phonet: properly unshare skbs in phonet_rcv()

2016-01-12T17:05:38+00:00

Ivaylo Dimitrov reported a regression caused by commit 7866a621043f
("dev: add per net_device packet type chains").

skb->dev becomes NULL and we crash in __netif_receive_skb_core().

Before above commit, different kind of bugs or corruptions could happen
without major crash.

But the root cause is that phonet_rcv() can queue skb without checking
if skb is shared or not.

Many thanks to Ivaylo Dimitrov for his help, diagnosis and tests.

Reported-by: Ivaylo Dimitrov 
Tested-by: Ivaylo Dimitrov 
Signed-off-by: Eric Dumazet 
Cc: Remi Denis-Courmont 
Signed-off-by: David S. Miller

net: Pass kern from net_proto_family.create to sk_alloc

2015-05-11T14:50:17+00:00

In preparation for changing how struct net is refcounted
on kernel sockets pass the knowledge that we are creating
a kernel socket from sock_create_kern through to sk_alloc.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

net: Remove iocb argument from sendmsg and recvmsg

2015-03-02T18:06:31+00:00

After TIPC doesn't depend on iocb argument in its internal
implementations of sendmsg() and recvmsg() hooks defined in proto
structure, no any user is using iocb argument in them at all now.
Then we can drop the redundant iocb argument completely from kinds of
implementations of both sendmsg() and recvmsg() in the entire
networking stack.

Cc: Christoph Hellwig 
Suggested-by: Al Viro 
Signed-off-by: Ying Xue 
Signed-off-by: David S. Miller

phonet netlink: allow multiple messages per skb in route dump

2015-01-19T21:20:17+00:00

My previous patch to this file changed the code to be bug-compatible
towards userspace. Unless userspace (which I wasn't able to find)
implements the dump reader by hand in a wrong way, this isn't needed.
If it uses libnl or similar code putting multiple messages into a
single SKB is far more efficient.

Change the code to do this. While at it, also clean it up and don't
use so many variables - just store the address in the callback args
directly.

Signed-off-by: Johannes Berg 
Signed-off-by: David S. Miller