[openib-general] RFC: deadlock in uverbs_cmd.c

[Roland Dreier]

    Michael> Hello!  uverbs_cmd currently locks both send and receive
    Michael> cq with down_write during ib_uverbs_create_qp operation.

It does?  It seems that the code in question is:

	scq = idr_read_cq(cmd.send_cq_handle, file->ucontext);
	rcq = idr_read_cq(cmd.recv_cq_handle, file->ucontext);

which should use down_read() and be safe.

    Michael> Comments?  Further, Roland, would you mind writing up
    Michael> something about the lock nesting in uverbs?

OK, I'll add that to my todo list.

 - R.