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

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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>
This commit is contained in:
Michael J. Ruhl
2017-05-04 05:15:15 -07:00
committed by Doug Ledford
parent 9b60d2cbe0
commit 8737ce95c4
6 changed files with 41 additions and 28 deletions
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2
drivers/infiniband/hw/hfi1/user_sdma.h
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@@ -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;