linux-stable.git/net/tipc/link.h, branch linux-3.13.y

tipc: message reassembly using fragment chain

2013-11-07T23:30:11+00:00

When the first fragment of a long data data message is received on a link, a
reassembly buffer large enough to hold the data from this and all subsequent
fragments of the message is allocated. The payload of each new fragment is
copied into this buffer upon arrival. When the last fragment is received, the
reassembled message is delivered upwards to the port/socket layer.

Not only is this an inefficient approach, but it may also cause bursts of
reassembly failures in low memory situations. since we may fail to allocate
the necessary large buffer in the first place. Furthermore, after 100 subsequent
such failures the link will be reset, something that in reality aggravates the
situation.

To remedy this problem, this patch introduces a different approach. Instead of
allocating a big reassembly buffer, we now append the arriving fragments
to a reassembly chain on the link, and deliver the whole chain up to the
socket layer once the last fragment has been received. This is safe because
the retransmission layer of a TIPC link always delivers packets in strict
uninterrupted order, to the reassembly layer as to all other upper layers.
Hence there can never be more than one fragment chain pending reassembly at
any given time in a link, and we can trust (but still verify) that the
fragments will be chained up in the correct order.

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

tipc: remove iovec length parameter from all sending functions

2013-10-18T17:20:42+00:00

tipc_msg_build() now copies message data from iovec to skb_buff
using memcpy_fromiovecend(), which doesn't need to be passed the
iovec length to perform the copying.

So we remove the parameter indicating iovec length in all
functions where TIPC messages are built and sent.

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

tipc: remove the bearer congestion mechanism

2012-11-22T01:07:25+00:00

Currently at the TIPC bearer layer there is the following congestion
mechanism:

Once sending packets has failed via that bearer, the bearer will be
flagged as being in congested state at once. During bearer congestion,
all packets arriving at link will be queued on the link's outgoing
buffer.  When we detect that the state of bearer congestion has
relaxed (e.g. some packets are received from the bearer) we will try
our best to push all packets in the link's outgoing buffer until the
buffer is empty, or until the bearer is congested again.

However, in fact the TIPC bearer never receives any feedback from the
device layer whether a send was successful or not, so it must always
assume it was successful. Therefore, the bearer congestion mechanism
as it exists currently is of no value.

But the bearer blocking state is still useful for us. For example,
when the physical media goes down/up, we need to change the state of
the links bound to the bearer.  So the code maintaing the state
information is not removed.

Signed-off-by: Ying Xue 
Signed-off-by: Paul Gortmaker

tipc: remove print_buf and deprecated log buffer code

2012-07-13T23:34:43+00:00

The internal log buffer handling functions can now safely be
removed since there is no code using it anymore.  Requests to
interact with the internal tipc log buffer over netlink (in
config.c) will report 'obsolete command'.

This represents the final removal of any references to a
struct print_buf, and the removal of the struct itself.
We also get rid of a TIPC specific Kconfig in the process.

Finally, log.h is removed since it is not needed anymore.

Signed-off-by: Erik Hugne 
Signed-off-by: Jon Maloy 
Signed-off-by: Paul Gortmaker

tipc: factor stats struct out of the larger link struct

2012-07-12T13:53:57+00:00

This is done to improve readability, and so that we can give
the struct a name that will allow us to declare a local
pointer to it in code, instead of having to always redirect
through the link struct to get to it.

Signed-off-by: Paul Gortmaker

tipc: compress out gratuitous extra carriage returns

2012-04-30T19:53:56+00:00

Some of the comment blocks are floating in limbo between two
functions, or between blocks of code.  Delete the extra line
feeds between any comment and its associated following block
of code, to be consistent with the majority of the rest of
the kernel.  Also delete trailing newlines at EOF and fix
a couple trivial typos in existing comments.

This is a 100% cosmetic change with no runtime impact.  We get
rid of over 500 lines of non-code, and being blank line deletes,
they won't even show up as noise in git blame.

Signed-off-by: Paul Gortmaker

tipc: rename struct link* to struct tipc_link*

2011-12-30T02:53:30+00:00

This converts the following:

	struct link		->	struct tipc_link
	struct link_req		->	struct tipc_link_req
	struct link_name	->	struct tipc_link_name

Signed-off-by: Paul Gortmaker

tipc: Allow use of buf_seqno() helper routine by unicast links

2011-12-27T16:33:54+00:00

Migrates the buf_seqno() helper routine from broadcast link level to
unicast link level so that it can be used both types of TIPC links.
This is a cosmetic change only, and does not affect the operation of TIPC.

Signed-off-by: Allan Stephens 
Signed-off-by: Paul Gortmaker

tipc: Ignore broadcast acknowledgements that are out-of-range

2011-12-27T16:33:53+00:00

Adds checks to TIPC's broadcast link so that it ignores any
acknowledgement message containing a sequence number that does not
correspond to an unacknowledged message currently in the broadcast
link's transmit queue.

This change prevents the broadcast link from becoming stalled if a
newly booted node receives stale broadcast link acknowledgement
information from another node that has not yet fully synchronized
its end of the broadcast link to reflect the current state of the
new node's end.

Signed-off-by: Allan Stephens 
Signed-off-by: Paul Gortmaker

tipc: Enhance sending of bulk name table messages

2011-09-18T02:55:10+00:00

Modifies the initial transfer of name table entries to a new neighboring
node so that the messages are enqueued as a unit, rather than individually.

The revised algorithm now locates the link carrying the message only once,
and eliminates unnecessary checks for link congestion, message fragmentation,
and message bundling that are not required when sending these messages.

Signed-off-by: Allan Stephens 
Signed-off-by: Paul Gortmaker