IB/hfi1: Fix an assign/ordering issue with shared context IDs

The current algorithm for generating sub-context IDs is FILO.  If the
contexts are not closed in that order, the uniqueness of the ID will be
compromised. I.e. logging the creation/deletion of context IDs with an
application that assigns and closes in a FIFO order reveals:

cache_id: assign: uctxt: 3    sub_ctxt: 0
cache_id: assign: uctxt: 3    sub_ctxt: 1
cache_id: assign: uctxt: 3    sub_ctxt: 2
cache_id: close:  uctxt: 3    sub_ctxt: 0
cache_id: assign: uctxt: 3    sub_ctxt: 2 <<<

The sub_ctxt ID 2 is reused incorrectly.

Update the sub-context ID assign algorithm to use a bitmask of in_use
contexts.  The new algorithm will allow the contexts to be closed in any
order, and will only re-use unused contexts.

Size subctxt and subctxt_cnt to match the user API size.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/hfi1/user_sdma.h b/drivers/infiniband/hw/hfi1/user_sdma.h
index 9181d7cbe8f6..e5b10aefe212 100644
--- a/drivers/infiniband/hw/hfi1/user_sdma.h
+++ b/drivers/infiniband/hw/hfi1/user_sdma.h
@@ -58,7 +58,7 @@ extern uint extended_psn;
 struct hfi1_user_sdma_pkt_q {
 	struct list_head list;
 	unsigned ctxt;
-	unsigned subctxt;
+	u16 subctxt;
 	u16 n_max_reqs;
 	atomic_t n_reqs;
 	u16 reqidx;