ipq40xx: essedma: Add fix for memory allocation issues

This patch adds a ChromiumOS 3.18 patch [0] that fixes memory
allocation issues under memory pressure by keeping track
of missed allocs and rectify the omission at a later date.
It also adds ethtool counters for memory allocation
failures accounting so this can be verified.

[0] <https://chromium.googlesource.com/chromiumos/third_party/kernel/+/d4e1e4ce6801f9eddce056c58f5a288864955265>

Reported-by: Chen Minqiang <ptpt52@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

1 files changed, 197 insertions, 0 deletions

diff --git a/target/linux/ipq40xx/patches-4.14/714-essedma-add-fix-for-memory-allocation.patch b/target/linux/ipq40xx/patches-4.14/714-essedma-add-fix-for-memory-allocation.patch
new file mode 100644
index 0000000000..5b9fcf780c
--- /dev/null
+++ b/target/linux/ipq40xx/patches-4.14/714-essedma-add-fix-for-memory-allocation.patch
@@ -0,0 +1,197 @@
+From 72c050acbc425ef99313d5c2e4c866e25567e569 Mon Sep 17 00:00:00 2001
+From: Rakesh Nair <ranair@codeaurora.org>
+Date: Thu, 8 Jun 2017 14:29:20 +0530
+Subject: [PATCH] CHROMIUM: net: qualcomm: Add fix for memory allocation issues
+
+Added ethtool counters for memory allocation failures accounting.
+Added support to track number of allocation failures that could
+not be fulfilled in the current iteration in the rx descriptor
+field and use the info to allocate in the subsequent iteration.
+
+Change-Id: Ie4fd3b6cf25304e5db2c9247a498791e7e9bb4aa
+Signed-off-by: Rakesh Nair <ranair@codeaurora.org>
+Signed-off-by: Kan Yan <kyan@google.com>
+Reviewed-on: https://chromium-review.googlesource.com/535419
+Reviewed-by: Grant Grundler <grundler@chromium.org>
+---
+ drivers/net/ethernet/qualcomm/essedma/edma.c  | 54 ++++++++++++++-----
+ drivers/net/ethernet/qualcomm/essedma/edma.h  |  2 +
+ .../ethernet/qualcomm/essedma/edma_ethtool.c  |  1 +
+ 3 files changed, 43 insertions(+), 14 deletions(-)
+
+--- a/drivers/net/ethernet/qualcomm/essedma/edma.c
++++ b/drivers/net/ethernet/qualcomm/essedma/edma.c
+@@ -103,6 +103,9 @@ static int edma_alloc_rx_ring(struct edm
+ 		return -ENOMEM;
+ 	}
+ 
++	/* Initialize pending_fill */
++	erxd->pending_fill = 0;
++
+ 	return 0;
+ }
+ 
+@@ -185,11 +188,8 @@ static int edma_alloc_rx_buf(struct edma
+ 	u16 prod_idx, length;
+ 	u32 reg_data;
+ 
+-	if (cleaned_count > erdr->count) {
+-		dev_err(&pdev->dev, "Incorrect cleaned_count %d",
+-		       cleaned_count);
+-		return -1;
+-	}
++	if (cleaned_count > erdr->count)
++		cleaned_count = erdr->count - 1;
+ 
+ 	i = erdr->sw_next_to_fill;
+ 
+@@ -199,6 +199,9 @@ static int edma_alloc_rx_buf(struct edma
+ 
+ 		if (sw_desc->flags & EDMA_SW_DESC_FLAG_SKB_REUSE) {
+ 			skb = sw_desc->skb;
++
++			/* Clear REUSE Flag */
++			sw_desc->flags &= ~EDMA_SW_DESC_FLAG_SKB_REUSE;
+ 		} else {
+ 			/* alloc skb */
+ 			skb = netdev_alloc_skb_ip_align(edma_netdev[0], length);
+@@ -264,6 +267,13 @@ static int edma_alloc_rx_buf(struct edma
+ 	reg_data &= ~EDMA_RFD_PROD_IDX_BITS;
+ 	reg_data |= prod_idx;
+ 	edma_write_reg(EDMA_REG_RFD_IDX_Q(queue_id), reg_data);
++
++	/* If we couldn't allocate all the buffers
++	 * we increment the alloc failure counters
++	 */
++	if (cleaned_count)
++		edma_cinfo->edma_ethstats.rx_alloc_fail_ctr++;
++
+ 	return cleaned_count;
+ }
+ 
+@@ -534,7 +544,7 @@ static int edma_rx_complete_paged(struct
+  * edma_rx_complete()
+  *	Main api called from the poll function to process rx packets.
+  */
+-static void edma_rx_complete(struct edma_common_info *edma_cinfo,
++static u16 edma_rx_complete(struct edma_common_info *edma_cinfo,
+ 			    int *work_done, int work_to_do, int queue_id,
+ 			    struct napi_struct *napi)
+ {
+@@ -554,6 +564,7 @@ static void edma_rx_complete(struct edma
+ 	u16 count = erdr->count, rfd_avail;
+ 	u8 queue_to_rxid[8] = {0, 0, 1, 1, 2, 2, 3, 3};
+ 
++	cleaned_count = erdr->pending_fill;
+ 	sw_next_to_clean = erdr->sw_next_to_clean;
+ 
+ 	edma_read_reg(EDMA_REG_RFD_IDX_Q(queue_id), &data);
+@@ -652,12 +663,13 @@ static void edma_rx_complete(struct edma
+ 						(*work_done)++;
+ 						drop_count = 0;
+ 					}
+-					if (cleaned_count == EDMA_RX_BUFFER_WRITE) {
++					if (cleaned_count >= EDMA_RX_BUFFER_WRITE) {
+ 						/* If buffer clean count reaches 16, we replenish HW buffers. */
+ 						ret_count = edma_alloc_rx_buf(edma_cinfo, erdr, cleaned_count, queue_id);
+ 						edma_write_reg(EDMA_REG_RX_SW_CONS_IDX_Q(queue_id),
+ 							      sw_next_to_clean);
+ 						cleaned_count = ret_count;
++						erdr->pending_fill = ret_count;
+ 					}
+ 					continue;
+ 				}
+@@ -730,11 +742,12 @@ static void edma_rx_complete(struct edma
+ 			adapter->stats.rx_bytes += length;
+ 
+ 			/* Check if we reached refill threshold */
+-			if (cleaned_count == EDMA_RX_BUFFER_WRITE) {
++			if (cleaned_count >= EDMA_RX_BUFFER_WRITE) {
+ 				ret_count = edma_alloc_rx_buf(edma_cinfo, erdr, cleaned_count, queue_id);
+ 				edma_write_reg(EDMA_REG_RX_SW_CONS_IDX_Q(queue_id),
+ 					      sw_next_to_clean);
+ 				cleaned_count = ret_count;
++				erdr->pending_fill = ret_count;
+ 			}
+ 
+ 			/* At this point skb should go to stack */
+@@ -756,11 +769,17 @@ static void edma_rx_complete(struct edma
+ 	/* Refill here in case refill threshold wasn't reached */
+ 	if (likely(cleaned_count)) {
+ 		ret_count = edma_alloc_rx_buf(edma_cinfo, erdr, cleaned_count, queue_id);
+-		if (ret_count)
+-			dev_dbg(&pdev->dev, "Not all buffers was reallocated");
++		erdr->pending_fill = ret_count;
++		if (ret_count) {
++			if (net_ratelimit())
++				dev_dbg(&pdev->dev, "Not all buffers was reallocated");
++		}
++
+ 		edma_write_reg(EDMA_REG_RX_SW_CONS_IDX_Q(queue_id),
+ 			      erdr->sw_next_to_clean);
+ 	}
++
++	return erdr->pending_fill;
+ }
+ 
+ /* edma_delete_rfs_filter()
+@@ -2064,6 +2083,7 @@ int edma_poll(struct napi_struct *napi,
+ 	u32 shadow_rx_status, shadow_tx_status;
+ 	int queue_id;
+ 	int i, work_done = 0;
++	u16 rx_pending_fill;
+ 
+ 	/* Store the Rx/Tx status by ANDing it with
+ 	 * appropriate CPU RX?TX mask
+@@ -2097,13 +2117,19 @@ int edma_poll(struct napi_struct *napi,
+ 	 */
+ 	while (edma_percpu_info->rx_status) {
+ 		queue_id = ffs(edma_percpu_info->rx_status) - 1;
+-		edma_rx_complete(edma_cinfo, &work_done,
+-			        budget, queue_id, napi);
++		rx_pending_fill = edma_rx_complete(edma_cinfo, &work_done,
++						   budget, queue_id, napi);
+ 
+-		if (likely(work_done < budget))
++		if (likely(work_done < budget)) {
++			if (rx_pending_fill) {
++                          	/* reschedule poll() to refill rx buffer deficit */
++				work_done = budget;
++				break;
++			}
+ 			edma_percpu_info->rx_status &= ~(1 << queue_id);
+-		else
++		} else {
+ 			break;
++		}
+ 	}
+ 
+ 	/* Clear the status register, to avoid the interrupts to
+--- a/drivers/net/ethernet/qualcomm/essedma/edma.h
++++ b/drivers/net/ethernet/qualcomm/essedma/edma.h
+@@ -225,6 +225,7 @@ struct edma_ethtool_statistics {
+ 	u32 rx_q6_byte;
+ 	u32 rx_q7_byte;
+ 	u32 tx_desc_error;
++	u32 rx_alloc_fail_ctr;
+ };
+ 
+ struct edma_mdio_data {
+@@ -362,6 +363,7 @@ struct edma_rfd_desc_ring {
+ 	dma_addr_t dma; /* descriptor ring physical address */
+ 	u16 sw_next_to_fill; /* next descriptor to fill */
+ 	u16 sw_next_to_clean; /* next descriptor to clean */
++	u16 pending_fill; /* fill pending from previous iteration */
+ };
+ 
+ /* edma_rfs_flter_node - rfs filter node in hash table */
+--- a/drivers/net/ethernet/qualcomm/essedma/edma_ethtool.c
++++ b/drivers/net/ethernet/qualcomm/essedma/edma_ethtool.c
+@@ -78,6 +78,7 @@ static const struct edma_ethtool_stats e
+ 	{"rx_q6_byte", EDMA_STAT(rx_q6_byte)},
+ 	{"rx_q7_byte", EDMA_STAT(rx_q7_byte)},
+ 	{"tx_desc_error", EDMA_STAT(tx_desc_error)},
++	{"rx_alloc_fail_ctr", EDMA_STAT(rx_alloc_fail_ctr)},
+ };
+ 
+ #define EDMA_STATS_LEN ARRAY_SIZE(edma_gstrings_stats)