Hello,
sorry, I'm late for the party :-) 
But I found that this patch decreases the performance of ISO-TP Stack.

I have created two testscripts where one plays the server and the 
other one is running a test and measuring the time how long
it takes to transfer an ISO-TP Frame with 1000 Bytes.

Without this patch it takes about 35ms to transfer the frame,
with this patch it takes about 145ms over vcan0.

Anyone an idea on this?

Sven


bring up a vcan0 interface with:
sudo modprobe vcan
sudo ip link add dev vcan0 type vcan
sudo ifconfig vcan0 up

here are the scripts:

--- isotp_server.sh ---

#!/bin/bash
iface=vcan0
echo "Wait for Messages on $iface"
while true; do
    exec 3< <(isotprecv -s 77E -d 714 -b F -p AA:AA $iface)
    rxpid=$!
    wait $rxpid
    output=$(cat <&3)
    echo "7F 01 11" | isotpsend -s 77E -d 714 -p AA:AA -L 16:8:0 $iface
done

--- isotp_test.sh ---

#!/bin/bash
databyte=01
numbytes=1000
iface=vcan0
echo "Test iso-tp with $numbytes byte frames on $iface (data:$databyte)"
message="01 " # invalid service 01
for (( i=1; i<=$numbytes; i++ ))
do
   message="$message$databyte "
done
i=1
timemin=10000
timemax=0
timesum=0
while true; do
    ts=$(date +%s%N)
    exec 3< <(isotprecv -s 714 -d 77E -b 5 $iface)
    rxpid=$!
    echo $message | isotpsend -s 714 -d 77E -p AA:AA -L 16:8:0 $iface
    wait $rxpid
    output=$(cat <&3)
    timediff=$((($(date +%s%N) - $ts)/1000000))
    if [ "7F 01 11 " != "$output" ]; then
        echo "ERROR: $i >$output<"
        break
    fi
    if [ $timediff -gt $timemax ]; then
        timemax=$timediff
    fi
    if [ $timediff -lt $timemin ]; then
        timemin=$timediff
    fi
    ((timesum=timesum+timediff))
    timeavg=$(echo "$timesum / $i" | bc -l)
    printf "%5d / curr:%5d / min:%5d / max:%5d / avg:%7.1f\n" $i $timediff $timemin $timemax $timeavg
    ((i=i+1))
done
------

Sven Schuchmann
Schleißheimer Soft- und
Hardwareentwicklung GmbH
Am Kalkofen 10
61206 Nieder-Wöllstadt
GERMANY
Phone: +49 6034 9148 711
Fax: +49 6034 9148 91
Email: schuchmann@schleissheimer.de

Court of Registration: Amtsgericht Friedberg
Registration Number: HRB 1581
Management Board:
Hans-Joachim Schleißheimer
Christine Schleißheimer