Skip napi_schedule if ib_poll_cq fails (v2)

Skip napi_schedule if ib_poll_cq fails (v2)

[Yuval Shaia]

v0 -> v1:
	* Initialize n before use

v1 -> v2
	* Add reviewers

[PATCH v2] IB/ipoib: Skip napi_schedule if ib_poll_cq fails
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[PATCH v2] IB/ipoib: Skip napi_schedule if ib_poll_cq fails

[Yuval Shaia]

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 <yuval.shaia-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Suggested-by: Håkon Bugge <haakon.bugge-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Acked-by: Santosh Shilimkar <santosh.shilimkar-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Reviewed-by: Eli Cohen <eli-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
---
 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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Re: Skip napi_schedule if ib_poll_cq fails (v2)

[Leon Romanovsky]

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On Wed, Jul 13, 2016 at 08:21:55AM -0700, Yuval Shaia wrote:
> v0 -> v1:
> 	* Initialize n before use
> 
> v1 -> v2
> 	* Add reviewers

You don't need to resend patches with tags changes only.
Patchworks handles it and adds automatically when Doug
collects them before apply.

And it will be great if you avoid adding cover letter for one patch.

Thanks

> 
> [PATCH v2] IB/ipoib: Skip napi_schedule if ib_poll_cq fails
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
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Re: Skip napi_schedule if ib_poll_cq fails (v2)

[Yuval Shaia]

On Wed, Jul 13, 2016 at 06:32:52PM +0300, Leon Romanovsky wrote:
> On Wed, Jul 13, 2016 at 08:21:55AM -0700, Yuval Shaia wrote:
> > v0 -> v1:
> > 	* Initialize n before use
> > 
> > v1 -> v2
> > 	* Add reviewers
> 
> You don't need to resend patches with tags changes only.
> Patchworks handles it and adds automatically when Doug
> collects them before apply.

I also added some off-list reviewers.

> 
> And it will be great if you avoid adding cover letter for one patch.

Sure, will do.

> 
> Thanks
> 
> > 
> > [PATCH v2] IB/ipoib: Skip napi_schedule if ib_poll_cq fails
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html


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Re: Skip napi_schedule if ib_poll_cq fails (v2)

[Leon Romanovsky]

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On Wed, Jul 13, 2016 at 09:44:10PM +0300, Yuval Shaia wrote:
> On Wed, Jul 13, 2016 at 06:32:52PM +0300, Leon Romanovsky wrote:
> > On Wed, Jul 13, 2016 at 08:21:55AM -0700, Yuval Shaia wrote:
> > > v0 -> v1:
> > > 	* Initialize n before use
> > > 
> > > v1 -> v2
> > > 	* Add reviewers
> > 
> > You don't need to resend patches with tags changes only.
> > Patchworks handles it and adds automatically when Doug
> > collects them before apply.
> 
> I also added some off-list reviewers.

You could reply to your email with forgotten tags.

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