[PATCH 1/3] x86: UV BAU destination timeout period

[Cliff Wickman]

Correct the calculation of a destination timeout period, which is used
to distinguish between a destination timeout and the situation where all
the target software ack resources are full and a request is returned
immediately.

The problem is that integer arithmetic was overflowing, yielding a very
large result.

Without this fix destination timeouts are identified as resource 'plugged'
events and an ipi method of resource releasing is unnecessarily employed.

Signed-off-by: Cliff Wickman <cpw@xxxxxxx>
---
 arch/x86/platform/uv/tlb_uv.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux/arch/x86/platform/uv/tlb_uv.c
===================================================================
--- linux.orig/arch/x86/platform/uv/tlb_uv.c
+++ linux/arch/x86/platform/uv/tlb_uv.c
@@ -1811,8 +1811,8 @@ static int calculate_destination_timeout
 		index = (mmr_image >> BAU_URGENCY_7_SHIFT) & BAU_URGENCY_7_MASK;
 		mmr_image = uv_read_local_mmr(UVH_TRANSACTION_TIMEOUT);
 		mult2 = (mmr_image >> BAU_TRANS_SHIFT) & BAU_TRANS_MASK;
-		base = timeout_base_ns[index];
-		ts_ns = base * mult1 * mult2;
+		ts_ns = timeout_base_ns[index];
+		ts_ns *= (mult1 * mult2);
 		ret = ts_ns / 1000;
 	} else {
 		/* 4 bits  0/1 for 10/80us base, 3 bits of multiplier */
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/