net: hns3: minor refactor related to desc_cb handling

mainline inclusion
from mainline-master
commit 26f1ccdf
category: feature
bugzilla: 173966
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=26f1ccdf609a9fb087f49a3782fdc2ade23cde82

----------------------------------------------------------------------

desc_cb is used to store mapping and freeing info for the
corresponding desc, which is used in the cleaning process.
There will be more desc_cb type coming up when supporting the
tx bounce buffer, change desc_cb type to bit-wise value in order
to reduce the desc_cb type checking operation in the data path.

Also move the desc_cb type definition to hns3_enet.h because it
is only used in hns3_enet.c, and declare a local variable desc_cb
in hns3_clear_desc() to reduce lines of code.
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NGuangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Reviewed-by: NYongxin Li <liyongxin1@huawei.com>
Signed-off-by: NJunxin Chen <chenjunxin1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/ethernet/hisilicon/hns3/hnae3.h

@@ -158,13 +158,6 @@ enum HNAE3_PF_CAP_BITS {
 #define ring_ptr_move_bw(ring, p) \
 	((ring)->p = ((ring)->p - 1 + (ring)->desc_num) % (ring)->desc_num)
 
-enum hns_desc_type {
-	DESC_TYPE_UNKNOWN,
-	DESC_TYPE_SKB,
-	DESC_TYPE_FRAGLIST_SKB,
-	DESC_TYPE_PAGE,
-};
-
 struct hnae3_handle;
 
 struct hnae3_queue {

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

@@ -1413,7 +1413,7 @@ static int hns3_fill_skb_desc(struct hns3_enet_ring *ring,
 }
 
 static int hns3_fill_desc(struct hns3_enet_ring *ring, void *priv,
-			  unsigned int size, enum hns_desc_type type)
+			  unsigned int size, unsigned int type)
 {
 #define HNS3_LIKELY_BD_NUM	1
 
@@ -1425,8 +1425,7 @@ static int hns3_fill_desc(struct hns3_enet_ring *ring, void *priv,
 	int k, sizeoflast;
 	dma_addr_t dma;
 
-	if (type == DESC_TYPE_FRAGLIST_SKB ||
-	    type == DESC_TYPE_SKB) {
+	if (type & (DESC_TYPE_FRAGLIST_SKB | DESC_TYPE_SKB)) {
 		struct sk_buff *skb = (struct sk_buff *)priv;
 
 		dma = dma_map_single(dev, skb->data, size, DMA_TO_DEVICE);
@@ -1704,6 +1703,7 @@ static void hns3_clear_desc(struct hns3_enet_ring *ring, int next_to_use_orig)
 
 	for (i = 0; i < ring->desc_num; i++) {
 		struct hns3_desc *desc = &ring->desc[ring->next_to_use];
+		struct hns3_desc_cb *desc_cb;
 
 		memset(desc, 0, sizeof(*desc));
 
@@ -1714,31 +1714,27 @@ static void hns3_clear_desc(struct hns3_enet_ring *ring, int next_to_use_orig)
 		/* rollback one */
 		ring_ptr_move_bw(ring, next_to_use);
 
-		if (!ring->desc_cb[ring->next_to_use].dma)
+		desc_cb = &ring->desc_cb[ring->next_to_use];
+
+		if (!desc_cb->dma)
 			continue;
 
 		/* unmap the descriptor dma address */
-		if (ring->desc_cb[ring->next_to_use].type == DESC_TYPE_SKB ||
-		    ring->desc_cb[ring->next_to_use].type ==
-		    DESC_TYPE_FRAGLIST_SKB)
-			dma_unmap_single(dev,
-					 ring->desc_cb[ring->next_to_use].dma,
-					ring->desc_cb[ring->next_to_use].length,
-					DMA_TO_DEVICE);
-		else if (ring->desc_cb[ring->next_to_use].length)
-			dma_unmap_page(dev,
-				       ring->desc_cb[ring->next_to_use].dma,
-				       ring->desc_cb[ring->next_to_use].length,
+		if (desc_cb->type & (DESC_TYPE_SKB | DESC_TYPE_FRAGLIST_SKB))
+			dma_unmap_single(dev, desc_cb->dma, desc_cb->length,
+					 DMA_TO_DEVICE);
+		else if (desc_cb->length)
+			dma_unmap_page(dev, desc_cb->dma, desc_cb->length,
 				       DMA_TO_DEVICE);
 
-		ring->desc_cb[ring->next_to_use].length = 0;
-		ring->desc_cb[ring->next_to_use].dma = 0;
-		ring->desc_cb[ring->next_to_use].type = DESC_TYPE_UNKNOWN;
+		desc_cb->length = 0;
+		desc_cb->dma = 0;
+		desc_cb->type = DESC_TYPE_UNKNOWN;
 	}
 }
 
 static int hns3_fill_skb_to_desc(struct hns3_enet_ring *ring,
-				 struct sk_buff *skb, enum hns_desc_type type)
+				 struct sk_buff *skb, unsigned int type)
 {
 	unsigned int size = skb_headlen(skb);
 	struct sk_buff *frag_skb;
@@ -2859,7 +2855,7 @@ static int hns3_alloc_buffer(struct hns3_enet_ring *ring,
 static void hns3_free_buffer(struct hns3_enet_ring *ring,
 			     struct hns3_desc_cb *cb, int budget)
 {
-	if (cb->type == DESC_TYPE_SKB)
+	if (cb->type & DESC_TYPE_SKB)
 		napi_consume_skb(cb->priv, budget);
 	else if (!HNAE3_IS_TX_RING(ring) && cb->pagecnt_bias)
 		__page_frag_cache_drain(cb->priv, cb->pagecnt_bias);
@@ -2880,7 +2876,7 @@ static int hns3_map_buffer(struct hns3_enet_ring *ring, struct hns3_desc_cb *cb)
 static void hns3_unmap_buffer(struct hns3_enet_ring *ring,
 			      struct hns3_desc_cb *cb)
 {
-	if (cb->type == DESC_TYPE_SKB || cb->type == DESC_TYPE_FRAGLIST_SKB)
+	if (cb->type & (DESC_TYPE_SKB | DESC_TYPE_FRAGLIST_SKB))
 		dma_unmap_single(ring_to_dev(ring), cb->dma, cb->length,
 				 ring_to_dma_dir(ring));
 	else if (cb->length)
@@ -3037,7 +3033,7 @@ static bool hns3_nic_reclaim_desc(struct hns3_enet_ring *ring,
 
 		desc_cb = &ring->desc_cb[ntc];
 
-		if (desc_cb->type == DESC_TYPE_SKB) {
+		if (desc_cb->type & DESC_TYPE_SKB) {
 			(*pkts)++;
 			(*bytes) += desc_cb->send_bytes;
 		}

drivers/net/ethernet/hisilicon/hns3/hns3_enet.h

@@ -299,6 +299,13 @@ struct __packed hns3_desc {
 	};
 };
 
+enum hns3_desc_type {
+	DESC_TYPE_UNKNOWN		= 0,
+	DESC_TYPE_SKB			= 1 << 0,
+	DESC_TYPE_FRAGLIST_SKB		= 1 << 1,
+	DESC_TYPE_PAGE			= 1 << 2,
+};
+
 struct hns3_desc_cb {
 	dma_addr_t dma; /* dma address of this desc */
 	void *buf;      /* cpu addr for a desc */