From: Kaike Wan <kaike.wan@intel.com>
Date: Sat, 17 Jun 2017 10:37:26 -0700
Subject: IB/rdmavt: Setting of QP timeout can overflow jiffies computation
Patch-mainline: v4.13-rc2
Git-commit: a25ce4270bfdd522207b02f81a594c7d1746b697
References: bsc#1058717 FATE#322789
Current computation of qp->timeout_jiffies in rvt_modify_qp() will cause
overflow due to the fact that the input to the function usecs_to_jiffies
is only 32-bit ( unsigned int). Overflow will occur when attr->timeout is
equal to or greater than 30. The consequence is unnecessarily excessive
retry and thus degradation of the system performance.
This patch fixes the problem by limiting the input to 5-bit and calling
usecs_to_jiffies() before multiplying the scaling factor.
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/infiniband/sw/rdmavt/qp.c | 4 +---
include/rdma/rdmavt_qp.h | 14 ++++++++++++++
2 files changed, 15 insertions(+), 3 deletions(-)
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/drivers/infiniband/sw/rdmavt/qp.c
@@ -1258,9 +1258,7 @@ int rvt_modify_qp(struct ib_qp *ibqp, st
if (attr_mask & IB_QP_TIMEOUT) {
qp->timeout = attr->timeout;
- qp->timeout_jiffies =
- usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
- 1000UL);
+ qp->timeout_jiffies = rvt_timeout_to_jiffies(qp->timeout);
}
if (attr_mask & IB_QP_QKEY)
--- a/include/rdma/rdmavt_qp.h
+++ b/include/rdma/rdmavt_qp.h
@@ -647,6 +647,20 @@ static inline u32 rvt_div_mtu(struct rvt
return len >> qp->log_pmtu;
}
+/**
+ * rvt_timeout_to_jiffies - Convert a ULP timeout input into jiffies
+ * @timeout - timeout input(0 - 31).
+ *
+ * Return a timeout value in jiffies.
+ */
+static inline unsigned long rvt_timeout_to_jiffies(u8 timeout)
+{
+ if (timeout > 31)
+ timeout = 31;
+
+ return usecs_to_jiffies(1U << timeout) * 4096UL / 1000UL;
+}
+
extern const int ib_rvt_state_ops[];
struct rvt_dev_info;