[PATCH net v6 1/2] net/ps3_gelic_net: Fix RX sk_buff length

[Geoff Levand <geoff@infradead.org>]

The Gelic Ethernet device needs to have the RX sk_buffs aligned to
GELIC_NET_RXBUF_ALIGN and the length of the RX sk_buffs must be a
multiple of GELIC_NET_RXBUF_ALIGN.

The current Gelic Ethernet driver was not allocating sk_buffs large
enough to allow for this alignment.

Fixes various randomly occurring runtime network errors.

Fixes: 02c1889166b4 ("ps3: gigabit ethernet driver for PS3, take3")
Signed-off-by: Geoff Levand <geoff@infradead.org>
---
 drivers/net/ethernet/toshiba/ps3_gelic_net.c | 66 +++++++++++---------
 drivers/net/ethernet/toshiba/ps3_gelic_net.h |  2 +-
 2 files changed, 39 insertions(+), 29 deletions(-)

diff --git a/drivers/net/ethernet/toshiba/ps3_gelic_net.c b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
index cf8de8a7a8a1..7e12e041acd3 100644
--- a/drivers/net/ethernet/toshiba/ps3_gelic_net.c
+++ b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
@@ -365,51 +365,61 @@ static int gelic_card_init_chain(struct gelic_card *card,
  *
  * allocates a new rx skb, iommu-maps it and attaches it to the descriptor.
  * Activate the descriptor state-wise
+ *
+ * Gelic RX sk_buffs must be aligned to GELIC_NET_RXBUF_ALIGN and the length
+ * must be a multiple of GELIC_NET_RXBUF_ALIGN.
  */
 static int gelic_descr_prepare_rx(struct gelic_card *card,
 				  struct gelic_descr *descr)
 {
-	int offset;
-	unsigned int bufsize;
+	struct device *dev = ctodev(card);
+	void *napi_buff;
 
 	if (gelic_descr_get_status(descr) !=  GELIC_DESCR_DMA_NOT_IN_USE)
 		dev_info(ctodev(card), "%s: ERROR status\n", __func__);
-	/* we need to round up the buffer size to a multiple of 128 */
-	bufsize = ALIGN(GELIC_NET_MAX_MTU, GELIC_NET_RXBUF_ALIGN);
-
-	/* and we need to have it 128 byte aligned, therefore we allocate a
-	 * bit more */
-	descr->skb = dev_alloc_skb(bufsize + GELIC_NET_RXBUF_ALIGN - 1);
-	if (!descr->skb) {
-		descr->buf_addr = 0; /* tell DMAC don't touch memory */
-		return -ENOMEM;
-	}
-	descr->buf_size = cpu_to_be32(bufsize);
+
 	descr->dmac_cmd_status = 0;
 	descr->result_size = 0;
 	descr->valid_size = 0;
 	descr->data_error = 0;
+	descr->buf_size = cpu_to_be32(GELIC_NET_MAX_MTU);
+
+	napi_buff = napi_alloc_frag_align(GELIC_NET_MAX_MTU,
+		GELIC_NET_RXBUF_ALIGN);
+
+	if (unlikely(!napi_buff)) {
+		descr->skb = NULL;
+		descr->buf_addr = 0;
+		descr->buf_size = 0;
+		return -ENOMEM;
+	}
+
+	descr->skb = napi_build_skb(napi_buff, GELIC_NET_MAX_MTU);
+
+	if (unlikely(!descr->skb)) {
+		skb_free_frag(napi_buff);
+		descr->skb = NULL;
+		descr->buf_addr = 0;
+		descr->buf_size = 0;
+		return -ENOMEM;
+	}
+
+	descr->buf_addr = cpu_to_be32(dma_map_single(dev, napi_buff,
+		GELIC_NET_MAX_MTU, DMA_FROM_DEVICE));
 
-	offset = ((unsigned long)descr->skb->data) &
-		(GELIC_NET_RXBUF_ALIGN - 1);
-	if (offset)
-		skb_reserve(descr->skb, GELIC_NET_RXBUF_ALIGN - offset);
-	/* io-mmu-map the skb */
-	descr->buf_addr = cpu_to_be32(dma_map_single(ctodev(card),
-						     descr->skb->data,
-						     GELIC_NET_MAX_MTU,
-						     DMA_FROM_DEVICE));
 	if (!descr->buf_addr) {
-		dev_kfree_skb_any(descr->skb);
+		skb_free_frag(napi_buff);
 		descr->skb = NULL;
-		dev_info(ctodev(card),
-			 "%s:Could not iommu-map rx buffer\n", __func__);
+		descr->buf_addr = 0;
+		descr->buf_size = 0;
+		dev_err_once(dev, "%s:Could not iommu-map rx buffer\n",
+			__func__);
 		gelic_descr_set_status(descr, GELIC_DESCR_DMA_NOT_IN_USE);
 		return -ENOMEM;
-	} else {
-		gelic_descr_set_status(descr, GELIC_DESCR_DMA_CARDOWNED);
-		return 0;
 	}
+
+	gelic_descr_set_status(descr, GELIC_DESCR_DMA_CARDOWNED);
+	return 0;
 }
 
 /**
diff --git a/drivers/net/ethernet/toshiba/ps3_gelic_net.h b/drivers/net/ethernet/toshiba/ps3_gelic_net.h
index 68f324ed4eaf..d3868eb7234c 100644
--- a/drivers/net/ethernet/toshiba/ps3_gelic_net.h
+++ b/drivers/net/ethernet/toshiba/ps3_gelic_net.h
@@ -19,7 +19,7 @@
 #define GELIC_NET_RX_DESCRIPTORS        128 /* num of descriptors */
 #define GELIC_NET_TX_DESCRIPTORS        128 /* num of descriptors */
 
-#define GELIC_NET_MAX_MTU               VLAN_ETH_FRAME_LEN
+#define GELIC_NET_MAX_MTU               1920
 #define GELIC_NET_MIN_MTU               VLAN_ETH_ZLEN
 #define GELIC_NET_RXBUF_ALIGN           128
 #define GELIC_CARD_RX_CSUM_DEFAULT      1 /* hw chksum */
-- 
2.34.1