linux.git/net/smc, 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: Move task_struct::signal and task_struct::sighand types and accessors into

2017-03-03T00:43:37+00:00

task_struct::signal and task_struct::sighand are pointers, which would normally make it
straightforward to not define those types in sched.h.

That is not so, because the types are accompanied by a myriad of APIs (macros and inline
functions) that dereference them.

Split the types and the APIs out of sched.h and move them into a new header, .

With this change sched.h does not know about 'struct signal' and 'struct sighand' anymore,
trying to put accessors into sched.h as a test fails the following way:

  ./include/linux/sched.h: In function ‘test_signal_types’:
  ./include/linux/sched.h:2461:18: error: dereferencing pointer to incomplete type ‘struct signal_struct’
                    ^

This reduces the size and complexity of sched.h significantly.

Update all headers and .c code that relied on getting the signal handling
functionality from  to include .

The list of affected files in the preparatory patch was partly generated by
grepping for the APIs, and partly by doing coverage build testing, both
all[yes|mod|def|no]config builds on 64-bit and 32-bit x86, and an array of
cross-architecture builds.

Nevertheless some (trivial) build breakage is still expected related to rare
Kconfig combinations and in-flight patches to various kernel code, but most
of it should be handled by this patch.

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

smc: some potential use after free bugs

2017-01-30T21:37:55+00:00

Say we got really unlucky and these failed on the last iteration, then
it could lead to a use after free bug.

Fixes: cd6851f30386 ("smc: remote memory buffers (RMBs)")
Signed-off-by: Dan Carpenter 
Signed-off-by: Ursula Braun 
Signed-off-by: David S. Miller

smc: ETH_ALEN as memcpy length for mac addresses

2017-01-12T14:47:01+00:00

When creating an SMC connection, there is a CLC (connection layer control)
handshake to prepare for RDMA traffic. The corresponding code is part of
commit 0cfdd8f92cac ("smc: connection and link group creation").
Mac addresses to be exchanged in the handshake are copied with a wrong
length of 12 instead of 6 bytes. Following code overwrites the wrongly
copied code, but nevertheless the correct length should already be used for
the preceding mac address copying. Use ETH_ALEN for the memcpy length with
mac addresses.

Signed-off-by: Ursula Braun 
Fixes: 0cfdd8f92cac ("smc: connection and link group creation")
Reported-by: Dan Carpenter 
Signed-off-by: David S. Miller

smc: netlink interface for SMC sockets

2017-01-09T21:07:41+00:00

Support for SMC socket monitoring via netlink sockets of protocol
NETLINK_SOCK_DIAG.

Signed-off-by: Ursula Braun 
Signed-off-by: David S. Miller

smc: socket closing and linkgroup cleanup

2017-01-09T21:07:40+00:00

smc_shutdown() and smc_release() handling
delayed linkgroup cleanup for linkgroups without connections

Signed-off-by: Ursula Braun 
Signed-off-by: David S. Miller

smc: receive data from RMBE

2017-01-09T21:07:40+00:00

move RMBE data into user space buffer and update managing cursors

Signed-off-by: Ursula Braun 
Signed-off-by: David S. Miller

smc: send data (through RDMA)

2017-01-09T21:07:40+00:00

copy data to kernel send buffer, and trigger RDMA write

Signed-off-by: Ursula Braun 
Signed-off-by: David S. Miller

smc: connection data control (CDC)

2017-01-09T21:07:40+00:00

send and receive CDC messages (via IB message send and CQE)

Signed-off-by: Ursula Braun 
Signed-off-by: David S. Miller

smc: link layer control (LLC)

2017-01-09T21:07:40+00:00

send and receive LLC messages CONFIRM_LINK (via IB message send and CQE)

Signed-off-by: Ursula Braun 
Signed-off-by: David S. Miller