ionic: Cleanups in the Tx hotpath code

Buffer DMA mapping happens in ionic_tx_map_skb() and this function is
called from ionic_tx() and ionic_tx_tso(). If ionic_tx_map_skb()
succeeds, but a failure is encountered later in ionic_tx() or
ionic_tx_tso() we aren't unmapping the buffers. This can be fixed in
ionic_tx() by changing functions it calls to return void because they
always return 0. For ionic_tx_tso(), there's an actual possibility that
we leave the buffers mapped, so fix this by introducing the helper
function ionic_tx_desc_unmap_bufs(). This function is also re-used
in ionic_tx_clean().

Fixes: 0f3154e6bcb3 ("ionic: Add Tx and Rx handling")
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 94384f5..d197a70 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -669,27 +669,37 @@ dma_fail:
        return -EIO;
 }
 
+static void ionic_tx_desc_unmap_bufs(struct ionic_queue *q,
+                                    struct ionic_desc_info *desc_info)
+{
+       struct ionic_buf_info *buf_info = desc_info->bufs;
+       struct device *dev = q->dev;
+       unsigned int i;
+
+       if (!desc_info->nbufs)
+               return;
+
+       dma_unmap_single(dev, (dma_addr_t)buf_info->dma_addr,
+                        buf_info->len, DMA_TO_DEVICE);
+       buf_info++;
+       for (i = 1; i < desc_info->nbufs; i++, buf_info++)
+               dma_unmap_page(dev, (dma_addr_t)buf_info->dma_addr,
+                              buf_info->len, DMA_TO_DEVICE);
+
+       desc_info->nbufs = 0;
+}
+
 static void ionic_tx_clean(struct ionic_queue *q,
                           struct ionic_desc_info *desc_info,
                           struct ionic_cq_info *cq_info,
                           void *cb_arg)
 {
-       struct ionic_buf_info *buf_info = desc_info->bufs;
        struct ionic_tx_stats *stats = q_to_tx_stats(q);
        struct ionic_qcq *qcq = q_to_qcq(q);
        struct sk_buff *skb = cb_arg;
-       struct device *dev = q->dev;
-       unsigned int i;
        u16 qi;
 
-       if (desc_info->nbufs) {
-               dma_unmap_single(dev, (dma_addr_t)buf_info->dma_addr,
-                                buf_info->len, DMA_TO_DEVICE);
-               buf_info++;
-               for (i = 1; i < desc_info->nbufs; i++, buf_info++)
-                       dma_unmap_page(dev, (dma_addr_t)buf_info->dma_addr,
-                                      buf_info->len, DMA_TO_DEVICE);
-       }
+       ionic_tx_desc_unmap_bufs(q, desc_info);
 
        if (!skb)
                return;
@@ -931,8 +941,11 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
                err = ionic_tx_tcp_inner_pseudo_csum(skb);
        else
                err = ionic_tx_tcp_pseudo_csum(skb);
-       if (err)
+       if (err) {
+               /* clean up mapping from ionic_tx_map_skb */
+               ionic_tx_desc_unmap_bufs(q, desc_info);
                return err;
+       }
 
        if (encap)
                hdrlen = skb_inner_transport_header(skb) - skb->data +
@@ -1003,8 +1016,8 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
        return 0;
 }
 
-static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb,
-                             struct ionic_desc_info *desc_info)
+static void ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb,
+                              struct ionic_desc_info *desc_info)
 {
        struct ionic_txq_desc *desc = desc_info->txq_desc;
        struct ionic_buf_info *buf_info = desc_info->bufs;
@@ -1038,12 +1051,10 @@ static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb,
                stats->crc32_csum++;
        else
                stats->csum++;
-
-       return 0;
 }
 
-static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb,
-                                struct ionic_desc_info *desc_info)
+static void ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb,
+                                 struct ionic_desc_info *desc_info)
 {
        struct ionic_txq_desc *desc = desc_info->txq_desc;
        struct ionic_buf_info *buf_info = desc_info->bufs;
@@ -1074,12 +1085,10 @@ static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb,
        desc->csum_offset = 0;
 
        stats->csum_none++;
-
-       return 0;
 }
 
-static int ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb,
-                             struct ionic_desc_info *desc_info)
+static void ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb,
+                              struct ionic_desc_info *desc_info)
 {
        struct ionic_txq_sg_desc *sg_desc = desc_info->txq_sg_desc;
        struct ionic_buf_info *buf_info = &desc_info->bufs[1];
@@ -1093,31 +1102,24 @@ static int ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb,
        }
 
        stats->frags += skb_shinfo(skb)->nr_frags;
-
-       return 0;
 }
 
 static int ionic_tx(struct ionic_queue *q, struct sk_buff *skb)
 {
        struct ionic_desc_info *desc_info = &q->info[q->head_idx];
        struct ionic_tx_stats *stats = q_to_tx_stats(q);
-       int err;
 
        if (unlikely(ionic_tx_map_skb(q, skb, desc_info)))
                return -EIO;
 
        /* set up the initial descriptor */
        if (skb->ip_summed == CHECKSUM_PARTIAL)
-               err = ionic_tx_calc_csum(q, skb, desc_info);
+               ionic_tx_calc_csum(q, skb, desc_info);
        else
-               err = ionic_tx_calc_no_csum(q, skb, desc_info);
-       if (err)
-               return err;
+               ionic_tx_calc_no_csum(q, skb, desc_info);
 
        /* add frags */
-       err = ionic_tx_skb_frags(q, skb, desc_info);
-       if (err)
-               return err;
+       ionic_tx_skb_frags(q, skb, desc_info);
 
        skb_tx_timestamp(skb);
        stats->pkts++;