Re: [PATCH v1] IB/ipoib: Skip napi_schedule if ib_poll_cq fails

Fix reviewed by...

Reviewed-by: Eli Cohen <eli-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

On Wed, Jul 13, 2016 at 04:53:01PM +0300, Eli Cohen wrote:

Reviewd-by: Eli Cohen [off-list ref]

BTW, did you actually hit this or are you sending this based on code
review?

On Wed, Jul 13, 2016 at 03:21:13AM -0700, Yuval Shaia wrote:

quoted

To avoid entering into endless loop when device can't poll CQE from CQ
driver should not reschedule if error is not -EAGAIN.

Signed-off-by: Yuval Shaia <redacted>
---
 drivers/infiniband/ulp/ipoib/ipoib.h       |    5 +++++
 drivers/infiniband/ulp/ipoib/ipoib_ib.c    |   13 ++++++++++++-
 drivers/infiniband/ulp/ipoib/ipoib_verbs.c |    1 +
 3 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index 4f7d9b4..1946149 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h

@@ -116,6 +116,8 @@ enum {
 	IPOIB_NON_CHILD		  = 0,
 	IPOIB_LEGACY_CHILD	  = 1,
 	IPOIB_RTNL_CHILD	  = 2,
+
+	IPOIB_MAX_CONSEQ_CQ_ERR	  = 10,
 };
 
 #define	IPOIB_OP_RECV   (1ul << 31)

@@ -347,6 +349,7 @@ struct ipoib_dev_priv {
 	u16		  pkey_index;
 	struct ib_pd	 *pd;
 	struct ib_cq	 *recv_cq;
+	int		  recv_conseq_cq_errs;
 	struct ib_cq	 *send_cq;
 	struct ib_qp	 *qp;
 	u32		  qkey;

@@ -772,6 +775,8 @@ static inline void ipoib_unregister_debugfs(void) { }
 	printk(level "%s: " format, ((struct ipoib_dev_priv *) priv)->dev->name , ## arg)
 #define ipoib_warn(priv, format, arg...)		\
 	ipoib_printk(KERN_WARNING, priv, format , ## arg)
+#define ipoib_crit(priv, format, arg...)		\
+	ipoib_printk(KERN_CRIT, priv, format , ## arg)
 
 extern int ipoib_sendq_size;
 extern int ipoib_recvq_size;

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index dc6d241..9395a24 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c

@@ -449,7 +449,8 @@ int ipoib_poll(struct napi_struct *napi, int budget)
 	int t;
 	int n, i;
 
-	done  = 0;
+	done = 0;
+	n = 0;
 
 poll_more:
 	while (done < budget) {

@@ -475,6 +476,16 @@ poll_more:
 			break;
 	}
 
+	if (unlikely(n < 0) && (n != -EAGAIN)) {
+		if (priv->recv_conseq_cq_errs++ >= IPOIB_MAX_CONSEQ_CQ_ERR) {
+			ipoib_crit(priv,
+				   "Too many poll_cq errors, last error: %d\n",
+				   n);
+			return done;
+		}
+	} else
+		priv->recv_conseq_cq_errs = 0;
+
 	if (done < budget) {
 		napi_complete(napi);
 		if (unlikely(ib_req_notify_cq(priv->recv_cq,

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
index 1e7cbba..6ca8bdd 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c

@@ -181,6 +181,7 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
 		printk(KERN_WARNING "%s: failed to create receive CQ\n", ca->name);
 		goto out_cm_dev_cleanup;
 	}
+	priv->recv_conseq_cq_errs = 0;
 
 	cq_attr.cqe = ipoib_sendq_size;
 	priv->send_cq = ib_create_cq(priv->ca, ipoib_send_comp_handler, NULL,

-- 
1.7.1

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