[ofa-general] help on /sys/class structure and rdma

[Roland Dreier]

 > I just found a bug in a drop I did for libcxgb3.  I changed the code
 > to read the adapter fw version sysfs file to attempt to check for
 > incompatible fw/lib cases.  I was reading this file in
 > cxgb3_driver_init():
 > 
 > /sys/class/infiniband_verbs/uverbs0/device/infiniband:cxgb3_0/fw_ver

I don't have any file like that in my system either.  Not sure where
it might be coming from for you.

However, I do have /sys/class/infiniband_verbs/uverbs1/ibdev (which
should be present everywhere), and that has "cxgb3_0" in it, which you
could use to get to /sys/class/infiniband/cxgb3_0/<whatever>.

libibverbs does set up ibv_device.ibdev_path with that path, but it
happens too late for your library initialization function
unfortunately.  So you can either wait until someone tries to create a
context and fail/warn then about firmware version, or you can
duplicate the libibverbs code to come up with that ibdev_path.

 - R.