[openib-general] [PATCH] The ibv_cmd_* create functions need to set the context.

[Michael S. Tsirkin]

> Quoting Roland Dreier <rdreier at cisco.com>:
> Subject: Re: [PATCH] The ibv_cmd_* create functions need to set the context.
> 
> Thanks, applied to master and stable branches.

Did you test it?
This patch (8b3d225476c99ea29a68109a7d40e5ef353d4388) causes ibv_ud_pingpong
to segfault on libmthca: libmthca never calls ibv_cmd_create_ah to context is now
never set.

Starting program: /usr/local/ofed/bin/ibv_ud_pingpong sw069
[Thread debugging using libthread_db enabled]
[New Thread 47299578320592 (LWP 5085)]
  local address:  LID 0x0002, QPN 0x090406, PSN 0x71bffb
  remote address: LID 0x0001, QPN 0x040406, PSN 0x92316a
4096000 bytes in 0.02 seconds = 1893.99 Mbit/sec
1000 iters in 0.02 seconds = 17.30 usec/iter

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 47299578320592 (LWP 5085)]
0x00002b04ca3b7263 in __ibv_destroy_ah (ah=0x5050b0) at src/verbs.c:475
475             return ah->context->ops.destroy_ah(ah);
(gdb) p ah->context
$1 = (struct ibv_context *) 0x0

I actually think this approach is a wrong one: context should be
set in common code like ibv_create_ah, not in ibv_cmd_ which is
a library function low level driver might or might not call.
And certainly this kind of change does not seem appropriate for stable branch.

I think the proper thing is for low level driver not to assume that
fields such as contex are intialized until create functions have returned.
Steve, pls fix your low level driver not to rely on this.

Roland, I have reverted this in OFED, please revert on master and stable.

-- 
MST