linux-toradex.git/net/tipc/subscr.c, branch v4.2.1

tipc: adjust locking policy of subscription

2015-05-04T19:04:01+00:00

Currently subscriber's lock protects not only subscriber's subscription
list but also all subscriptions linked into the list. However, as all
members of subscription are never changed after they are initialized,
it's unnecessary for subscription to be protected under subscriber's
lock. If the lock is used to only protect subscriber's subscription
list, the adjustment not only makes the locking policy simpler, but
also helps to avoid a deadlock which may happen once creating a
subscription is failed.

Signed-off-by: Ying Xue 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: involve reference counter for subscriber

2015-05-04T19:04:01+00:00

At present subscriber's lock is used to protect the subscription list
of subscriber as well as subscriptions linked into the list. While one
or all subscriptions are deleted through iterating the list, the
subscriber's lock must be held. Meanwhile, as deletion of subscription
may happen in subscription timer's handler, the lock must be grabbed
in the function as well. When subscription's timer is terminated with
del_timer_sync() during above iteration, subscriber's lock has to be
temporarily released, otherwise, deadlock may occur. However, the
temporary release may cause the double free of a subscription as the
subscription is not disconnected from the subscription list.

Now if a reference counter is introduced to subscriber, subscription's
timer can be asynchronously stopped with del_timer(). As a result, the
issue is not only able to be fixed, but also relevant code is pretty
readable and understandable.

Signed-off-by: Ying Xue 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: introduce tipc_subscrb_create routine

2015-05-04T19:04:01+00:00

Introducing a new function makes the purpose of tipc_subscrb_connect_cb
callback routine more clear.

Signed-off-by: Ying Xue 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: rename functions defined in subscr.c

2015-05-04T19:04:00+00:00

When a topology server accepts a connection request from its client,
it allocates a connection instance and a tipc_subscriber structure
object. The former is used to communicate with client, and the latter
is often treated as a subscriber which manages all subscription events
requested from a same client. When a topology server receives a request
of subscribing name services from a client through the connection, it
creates a tipc_subscription structure instance which is seen as a
subscription recording what name services are subscribed. In order to
manage all subscriptions from a same client, topology server links
them into the subscrp_list of the subscriber. So subscriber and
subscription completely represents different meanings respectively,
but function names associated with them make us so confused that we
are unable to easily tell which function is against subscriber and
which is to subscription. So we want to eliminate the confusion by
renaming them.

Signed-off-by: Ying Xue 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: fix nullpointer bug when subscribing to events

2015-02-27T23:18:47+00:00

If a subscription request is sent to a topology server
connection, and any error occurs (malformed request, oom
or limit reached) while processing this request, TIPC should
terminate the subscriber connection. While doing so, it tries
to access fields in an already freed (or never allocated)
subscription element leading to a nullpointer exception.
We fix this by removing the subscr_terminate function and
terminate the connection immediately upon any subscription
failure.

Signed-off-by: Erik Hugne 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: make subscriber server support net namespace

2015-01-12T21:24:33+00:00

TIPC establishes one subscriber server which allows users to subscribe
their interesting name service status. After tipc supports namespace,
one dedicated tipc stack instance is created for each namespace, and
each instance can be deemed as one independent TIPC node. As a result,
subscriber server must be built for each namespace.

Signed-off-by: Ying Xue 
Tested-by: Tero Aho 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: name tipc name table support net namespace

2015-01-12T21:24:33+00:00

TIPC name table is used to store the mapping relationship between
TIPC service name and socket port ID. When tipc supports namespace,
it allows users to publish service names only owned by a certain
namespace. Therefore, every namespace must have its private name
table to prevent service names published to one namespace from being
contaminated by other service names in another namespace. Therefore,
The name table global variable (ie, nametbl) and its lock must be
moved to tipc_net structure, and a parameter of namespace must be
added for necessary functions so that they can obtain name table
variable defined in tipc_net structure.

Signed-off-by: Ying Xue 
Tested-by: Tero Aho 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: remove unnecessary wrapper functions of kernel timer APIs

2015-01-12T21:24:31+00:00

Not only some wrapper function like k_term_timer() is empty, but also
some others including k_start_timer() and k_cancel_timer() don't return
back any value to its caller, what's more, there is no any component
in the kernel world to do such thing. Therefore, these timer interfaces
defined in tipc module should be purged.

Signed-off-by: Ying Xue 
Tested-by: Tero Aho 
Reviewed-by: Jon Maloy 
Signed-off-by: David S. Miller

tipc: remove unnecessary INIT_LIST_HEAD

2014-12-09T01:39:57+00:00

When a list_head variable is seen as a new entry to be added to a
list head, it's unnecessary to be initialized with INIT_LIST_HEAD().

Signed-off-by: Ying Xue 
Reviewed-by: Erik Hugne 
Reviewed-by: Jon Maloy 
Tested-by: Erik Hugne 
Signed-off-by: David S. Miller

tipc: remove include file port.h

2014-08-23T18:18:35+00:00

We move the inline functions in the file port.h to socket.c, and modify
their names accordingly.

We move struct tipc_port and some macros to socket.h.

Finally, we remove the file port.h.

Signed-off-by: Jon Maloy 
Reviewed-by: Erik Hugne 
Reviewed-by: Ying Xue 
Signed-off-by: David S. Miller