nfp: add a helper for wrapping descriptor index

We have a number of places where we calculate the descriptor
index based on a value which may have overflown.  Create a
macro for masking with the ring size.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net.h b/drivers/net/ethernet/netronome/nfp/nfp_net.h
index 66319a1026bb0eaffd263ffacb3b5a8d296ca276..7b9518cbe9658fe2144989efcdbff75662be91b3 100644 (file)
--- a/drivers/net/ethernet/netronome/nfp/nfp_net.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net.h
@@ -117,6 +117,9 @@ struct nfp_eth_table_port;
 struct nfp_net;
 struct nfp_net_r_vector;
 
+/* Convenience macro for wrapping descriptor index on ring size */
+#define D_IDX(ring, idx)       ((idx) & ((ring)->cnt - 1))
+
 /* Convenience macro for writing dma address into RX/TX descriptors */
 #define nfp_desc_set_dma_addr(desc, dma_addr)                          \
        do {                                                            \

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index a4c6878f1df1f9e518a30a4892924f243999df22..c64514f8ee65b78b2ce7ffcc3ec2ab388665bacf 100644 (file)
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -809,7 +809,7 @@ static int nfp_net_tx(struct sk_buff *skb, struct net_device *netdev)
        if (dma_mapping_error(dp->dev, dma_addr))
                goto err_free;
 
-       wr_idx = tx_ring->wr_p & (tx_ring->cnt - 1);
+       wr_idx = D_IDX(tx_ring, tx_ring->wr_p);
 
        /* Stash the soft descriptor of the head then initialize it */
        txbuf = &tx_ring->txbufs[wr_idx];
@@ -852,7 +852,7 @@ static int nfp_net_tx(struct sk_buff *skb, struct net_device *netdev)
                        if (dma_mapping_error(dp->dev, dma_addr))
                                goto err_unmap;
 
-                       wr_idx = (wr_idx + 1) & (tx_ring->cnt - 1);
+                       wr_idx = D_IDX(tx_ring, wr_idx + 1);
                        tx_ring->txbufs[wr_idx].skb = skb;
                        tx_ring->txbufs[wr_idx].dma_addr = dma_addr;
                        tx_ring->txbufs[wr_idx].fidx = f;
@@ -946,8 +946,7 @@ static void nfp_net_tx_complete(struct nfp_net_tx_ring *tx_ring)
                todo = qcp_rd_p + tx_ring->cnt - tx_ring->qcp_rd_p;
 
        while (todo--) {
-               idx = tx_ring->rd_p & (tx_ring->cnt - 1);
-               tx_ring->rd_p++;
+               idx = D_IDX(tx_ring, tx_ring->rd_p++);
 
                skb = tx_ring->txbufs[idx].skb;
                if (!skb)
@@ -1023,11 +1022,11 @@ static bool nfp_net_xdp_complete(struct nfp_net_tx_ring *tx_ring)
        done_all = todo <= NFP_NET_XDP_MAX_COMPLETE;
        todo = min(todo, NFP_NET_XDP_MAX_COMPLETE);
 
-       tx_ring->qcp_rd_p = (tx_ring->qcp_rd_p + todo) & (tx_ring->cnt - 1);
+       tx_ring->qcp_rd_p = D_IDX(tx_ring, tx_ring->qcp_rd_p + todo);
 
        done_pkts = todo;
        while (todo--) {
-               idx = tx_ring->rd_p & (tx_ring->cnt - 1);
+               idx = D_IDX(tx_ring, tx_ring->rd_p);
                tx_ring->rd_p++;
 
                done_bytes += tx_ring->txbufs[idx].real_len;
@@ -1063,7 +1062,7 @@ nfp_net_tx_ring_reset(struct nfp_net_dp *dp, struct nfp_net_tx_ring *tx_ring)
                struct sk_buff *skb;
                int idx, nr_frags;
 
-               idx = tx_ring->rd_p & (tx_ring->cnt - 1);
+               idx = D_IDX(tx_ring, tx_ring->rd_p);
                tx_buf = &tx_ring->txbufs[idx];
 
                skb = tx_ring->txbufs[idx].skb;
@@ -1216,7 +1215,7 @@ static void nfp_net_rx_give_one(const struct nfp_net_dp *dp,
 {
        unsigned int wr_idx;
 
-       wr_idx = rx_ring->wr_p & (rx_ring->cnt - 1);
+       wr_idx = D_IDX(rx_ring, rx_ring->wr_p);
 
        nfp_net_dma_sync_dev_rx(dp, dma_addr);
 
@@ -1254,7 +1253,7 @@ static void nfp_net_rx_ring_reset(struct nfp_net_rx_ring *rx_ring)
        unsigned int wr_idx, last_idx;
 
        /* Move the empty entry to the end of the list */
-       wr_idx = rx_ring->wr_p & (rx_ring->cnt - 1);
+       wr_idx = D_IDX(rx_ring, rx_ring->wr_p);
        last_idx = rx_ring->cnt - 1;
        rx_ring->rxbufs[wr_idx].dma_addr = rx_ring->rxbufs[last_idx].dma_addr;
        rx_ring->rxbufs[wr_idx].frag = rx_ring->rxbufs[last_idx].frag;
@@ -1522,7 +1521,7 @@ nfp_net_tx_xdp_buf(struct nfp_net_dp *dp, struct nfp_net_rx_ring *rx_ring,
                }
        }
 
-       wr_idx = tx_ring->wr_p & (tx_ring->cnt - 1);
+       wr_idx = D_IDX(tx_ring, tx_ring->wr_p);
 
        /* Stash the soft descriptor of the head then initialize it */
        txbuf = &tx_ring->txbufs[wr_idx];
@@ -1610,7 +1609,7 @@ static int nfp_net_rx(struct nfp_net_rx_ring *rx_ring, int budget)
                dma_addr_t new_dma_addr;
                void *new_frag;
 
-               idx = rx_ring->rd_p & (rx_ring->cnt - 1);
+               idx = D_IDX(rx_ring, rx_ring->rd_p);
 
                rxd = &rx_ring->rxds[idx];
                if (!(rxd->rxd.meta_len_dd & PCIE_DESC_RX_DD))