dpaa_eth: Handle buffer pool depletion

If the system gets into an out-of-memory state, we are unable to
refill the default buffer pool with new buffers. While this lasts,
just release any incoming frame back to the pool without further
processing.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@freescale.com>
Signed-off-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
Signed-off-by: Madalin Bucur <madalin.bucur@freescale.com>

Change-Id: Ia7cd0979adfa2d5c6f5be88017ed2bd0bfd202f8
Reviewed-on: http://git.am.freescale.net:8181/3335
Reviewed-by: Radulescu Ruxandra Ioana-B05472 <ruxandra.radulescu@freescale.com>
Tested-by: Review Code-CDREVIEW <CDREVIEW@freescale.com>
Reviewed-by: Sovaiala Cristian-Constantin-B39531 <Cristian.Sovaiala@freescale.com>
Reviewed-by: Fleming Andrew-AFLEMING <AFLEMING@freescale.com>

4 files changed, 27 insertions, 7 deletions

diff --git a/drivers/net/ethernet/freescale/dpa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpa/dpaa_eth.c
index cca3383..d09d6b9 100644
--- a/drivers/net/ethernet/freescale/dpa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpa/dpaa_eth.c
@@ -345,8 +345,14 @@ priv_rx_error_dqrr(struct qman_portal		*portal,
 		return qman_cb_dqrr_stop;
 	}
 
-	dpaa_eth_refill_bpools(percpu_priv);
-	_dpa_rx_error(net_dev, priv, percpu_priv, &dq->fd, fq->fqid);
+	if (unlikely(dpaa_eth_refill_bpools(percpu_priv)))
+		/* Unable to refill the buffer pool due to insufficient
+		 * system memory. Just release the frame back into the pool,
+		 * otherwise we'll soon end up with an empty buffer pool.
+		 */
+		dpa_fd_release(net_dev, &dq->fd);
+	else
+		_dpa_rx_error(net_dev, priv, percpu_priv, &dq->fd, fq->fqid);
 
 	return qman_cb_dqrr_consume;
 }
@@ -376,8 +382,15 @@ priv_rx_default_dqrr(struct qman_portal		*portal,
 	}
 
 	/* Vale of plenty: make sure we didn't run out of buffers */
-	dpaa_eth_refill_bpools(percpu_priv);
-	_dpa_rx(net_dev, priv, percpu_priv, &dq->fd, fq->fqid);
+
+	if (unlikely(dpaa_eth_refill_bpools(percpu_priv)))
+		/* Unable to refill the buffer pool due to insufficient
+		 * system memory. Just release the frame back into the pool,
+		 * otherwise we'll soon end up with an empty buffer pool.
+		 */
+		dpa_fd_release(net_dev, &dq->fd);
+	else
+		_dpa_rx(net_dev, priv, percpu_priv, &dq->fd, fq->fqid);
 
 	return qman_cb_dqrr_consume;
 }
diff --git a/drivers/net/ethernet/freescale/dpa/dpaa_eth.h b/drivers/net/ethernet/freescale/dpa/dpaa_eth.h
index e3e5d69..b3f4ec2 100644
--- a/drivers/net/ethernet/freescale/dpa/dpaa_eth.h
+++ b/drivers/net/ethernet/freescale/dpa/dpaa_eth.h
@@ -451,7 +451,7 @@ struct fm_port_fqs {
 
 /* functions with different implementation for SG and non-SG: */
 void dpa_make_private_pool(struct dpa_bp *dpa_bp);
-void dpaa_eth_refill_bpools(struct dpa_percpu_priv_s *percpu_priv);
+int dpaa_eth_refill_bpools(struct dpa_percpu_priv_s *percpu_priv);
 void __hot _dpa_rx(struct net_device *net_dev,
 		const struct dpa_priv_s *priv,
 		struct dpa_percpu_priv_s *percpu_priv,
diff --git a/drivers/net/ethernet/freescale/dpa/dpaa_eth_non_sg.c b/drivers/net/ethernet/freescale/dpa/dpaa_eth_non_sg.c
index 1d4d323..42a0448 100644
--- a/drivers/net/ethernet/freescale/dpa/dpaa_eth_non_sg.c
+++ b/drivers/net/ethernet/freescale/dpa/dpaa_eth_non_sg.c
@@ -153,7 +153,7 @@ void dpa_make_private_pool(struct dpa_bp *dpa_bp)
 /* Add buffers/(skbuffs) for Rx processing whenever bpool count falls below
  * REFILL_THRESHOLD.
  */
-void dpaa_eth_refill_bpools(struct dpa_percpu_priv_s *percpu_priv)
+int dpaa_eth_refill_bpools(struct dpa_percpu_priv_s *percpu_priv)
 {
 	int *countptr = percpu_priv->dpa_bp_count;
 	int count = *countptr;
@@ -169,6 +169,8 @@ void dpaa_eth_refill_bpools(struct dpa_percpu_priv_s *percpu_priv)
 		for (i = count; i < CONFIG_FSL_DPAA_ETH_MAX_BUF_COUNT; i += 8)
 			dpa_bp_add_8(dpa_bp, cpu);
 	}
+
+	return 0;
 }
 
 /* Cleanup function for outgoing frame descriptors that were built on Tx path,
diff --git a/drivers/net/ethernet/freescale/dpa/dpaa_eth_sg.c b/drivers/net/ethernet/freescale/dpa/dpaa_eth_sg.c
index 32086d4..7f0e870 100644
--- a/drivers/net/ethernet/freescale/dpa/dpaa_eth_sg.c
+++ b/drivers/net/ethernet/freescale/dpa/dpaa_eth_sg.c
@@ -159,7 +159,7 @@ void dpa_make_private_pool(struct dpa_bp *dpa_bp)
  * Add buffers/(pages) for Rx processing whenever bpool count falls below
  * REFILL_THRESHOLD.
  */
-void dpaa_eth_refill_bpools(struct dpa_percpu_priv_s *percpu_priv)
+int dpaa_eth_refill_bpools(struct dpa_percpu_priv_s *percpu_priv)
 {
 	int *countptr = percpu_priv->dpa_bp_count;
 	int count = *countptr;
@@ -179,6 +179,11 @@ void dpaa_eth_refill_bpools(struct dpa_percpu_priv_s *percpu_priv)
 		count += new_pages;
 	}
 	*countptr = count;
+
+	if (unlikely(*countptr < CONFIG_FSL_DPAA_ETH_MAX_BUF_COUNT))
+		return -ENOMEM;
+
+	return 0;
 }
 
 /* Cleanup function for outgoing frame descriptors that were built on Tx path,