Re: [PATCH] sctp: don't break the loop while meeting the active_path so as to find the matched transport

On 3/8/13, Neil Horman [off-list ref] wrote:

On Fri, Mar 08, 2013 at 03:39:37PM +0800, Xufeng Zhang wrote:

quoted

sctp_assoc_lookup_tsn() function searchs which transport a certain TSN
was sent on, if not found in the active_path transport, then go search
all the other transports in the peer's transport_addr_list, however, we
should continue to the next entry rather than break the loop when meet
the active_path transport.

Signed-off-by: Xufeng Zhang <redacted>
---
 net/sctp/associola.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 43cd0dd..d2709e2 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c

@@ -1079,7 +1079,7 @@ struct sctp_transport *sctp_assoc_lookup_tsn(struct

sctp_association *asoc,
 			transports) {

 		if (transport == active)
-			break;
+			continue;
 		list_for_each_entry(chunk, &transport->transmitted,
 				transmitted_list) {
 			if (key == chunk->subh.data_hdr->tsn) {
--
1.7.0.2

This works, but what might be better would be if we did a move to front
heuristic in sctp_assoc_set_primary.  E.g. when we set the active_path, move
the
requisite transport to the front of the transport_addr_list.  If we did
that,
then we could just do one for loop in sctp_assoc_lookup_tsn and wind up
implicitly check the active path first without having to check it seprately
and
skip it in the second for loop.

Thanks for your review, Neil!

I know what you mean, yes, it's most probably that the searched TSN was
transmitted in the currently active_path, but what should we do if not.

Check the comment in sctp_assoc_lookup_tsn() function:
/* Let's be hopeful and check the active_path first. */
/* If not found, go search all the other transports. */

It has checked the active_path first and then traverse all the other
transports in
the transport_addr_list except the active_path.

So what I want to fix here is the inconsistency between the function
should do and
the code actually does.



Thanks,
Xufeng

Neil

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