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[hermon] Randomise the high-order bits of queue pair numbers 

The Infiniband Communication Manager will refuse to establish a
connection if it believes the connection is already established.
There is no immediately obvious way to ask it to tear down the
existing connection and replace it; to issue a DREP we would need to
know the local and remote communication IDs used for the previous
connection setup.

We can work around this by randomising the high-order bits of the
queue pair number; these have no significance to the hardware, but are
sufficient to convince the IB CM that this is a different connection.
This commit is contained in:
Michael Brown 2009-08-09 20:38:35 +01:00
parent cf716a0ce6
commit 0b1222f233
2 changed files with 7 additions and 6 deletions
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9
src/drivers/infiniband/hermon.c
View File

@ -857,7 +857,8 @@ static int hermon_alloc_qpn ( struct ib_device *ibdev,
hermon );
return qpn_offset;
}
qp->qpn = ( hermon->qpn_base + qpn_offset );
qp->qpn = ( ( random() & HERMON_QPN_RANDOM_MASK ) |
( hermon->qpn_base + qpn_offset ) );
return 0;
default:
DBGC ( hermon, "Hermon %p unsupported QP type %d\n",
@ -877,7 +878,8 @@ static void hermon_free_qpn ( struct ib_device *ibdev,
struct hermon *hermon = ib_get_drvdata ( ibdev );
int qpn_offset;
qpn_offset = ( qp->qpn - hermon->qpn_base );
qpn_offset = ( ( qp->qpn & ~HERMON_QPN_RANDOM_MASK )
- hermon->qpn_base );
if ( qpn_offset >= 0 )
hermon_bitmask_free ( hermon->qp_inuse, qpn_offset, 1 );
}
@ -2529,8 +2531,7 @@ static int hermon_configure_special_qps ( struct hermon *hermon ) {
int rc;
/* Special QP block must be aligned on its own size */
hermon->special_qpn_base = ( ( HERMON_QPN_BASE +
hermon->cap.reserved_qps +
hermon->special_qpn_base = ( ( hermon->cap.reserved_qps +
HERMON_NUM_SPECIAL_QPS - 1 )
& ~( HERMON_NUM_SPECIAL_QPS - 1 ) );
hermon->qpn_base = ( hermon->special_qpn_base +

4
src/drivers/infiniband/hermon.h
View File

@ -422,8 +422,8 @@ struct hermon_recv_work_queue {
*/
#define HERMON_MAX_QPS 8
/** Base queue pair number */
#define HERMON_QPN_BASE 0x550000
/** Queue pair number randomisation mask */
#define HERMON_QPN_RANDOM_MASK 0xfff000
/** Hermon queue pair state */
enum hermon_queue_pair_state {