Revert "cxgb3: Check and handle the dma mapping errors"

This reverts commit f83331bab149e29fa2c49cf102c0cd8c3f1ce9f9.

As the tests PPC64 (powernv platform) show, IOMMU pages are leaking
when transferring big amount of small packets (<=64 bytes),
"ping -f" and waiting for 15 seconds is the simplest way to confirm the bug.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Santosh Rastapur <santosh@chelsio.com>
Cc: Jay Fenlason <fenlason@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Divy Le ray <divy@chelsio.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 83 deletions

diff --git a/drivers/net/ethernet/chelsio/cxgb3/sge.c b/drivers/net/ethernet/chelsio/cxgb3/sge.c
index 687ec4a8bb48..9c89dc8fe105 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/sge.c
@@ -455,11 +455,6 @@ static int alloc_pg_chunk(struct adapter *adapter, struct sge_fl *q,
                 q->pg_chunk.offset = 0;
                 mapping = pci_map_page(adapter->pdev, q->pg_chunk.page,
                                        0, q->alloc_size, PCI_DMA_FROMDEVICE);
-                if (unlikely(pci_dma_mapping_error(adapter->pdev, mapping))) {
-                        __free_pages(q->pg_chunk.page, order);
-                        q->pg_chunk.page = NULL;
-                        return -EIO;
-                }
                 q->pg_chunk.mapping = mapping;
         }
         sd->pg_chunk = q->pg_chunk;
@@ -954,75 +949,40 @@ static inline unsigned int calc_tx_descs(const struct sk_buff *skb)
         return flits_to_desc(flits);
 }
 
-
-/*      map_skb - map a packet main body and its page fragments
- *      @pdev: the PCI device
- *      @skb: the packet
- *      @addr: placeholder to save the mapped addresses
- *
- *      map the main body of an sk_buff and its page fragments, if any.
- */
-static int map_skb(struct pci_dev *pdev, const struct sk_buff *skb,
-                   dma_addr_t *addr)
-{
-        const skb_frag_t *fp, *end;
-        const struct skb_shared_info *si;
-
-        *addr = pci_map_single(pdev, skb->data, skb_headlen(skb),
-                               PCI_DMA_TODEVICE);
-        if (pci_dma_mapping_error(pdev, *addr))
-                goto out_err;
-
-        si = skb_shinfo(skb);
-        end = &si->frags[si->nr_frags];
-
-        for (fp = si->frags; fp < end; fp++) {
-                *++addr = skb_frag_dma_map(&pdev->dev, fp, 0, skb_frag_size(fp),
-                                           DMA_TO_DEVICE);
-                if (pci_dma_mapping_error(pdev, *addr))
-                        goto unwind;
-        }
-        return 0;
-
-unwind:
-        while (fp-- > si->frags)
-                dma_unmap_page(&pdev->dev, *--addr, skb_frag_size(fp),
-                               DMA_TO_DEVICE);
-
-        pci_unmap_single(pdev, addr[-1], skb_headlen(skb), PCI_DMA_TODEVICE);
-out_err:
-        return -ENOMEM;
-}
-
 /**
- *      write_sgl - populate a scatter/gather list for a packet
+ *      make_sgl - populate a scatter/gather list for a packet
  *      @skb: the packet
  *      @sgp: the SGL to populate
  *      @start: start address of skb main body data to include in the SGL
  *      @len: length of skb main body data to include in the SGL
- *      @addr: the list of the mapped addresses
+ *      @pdev: the PCI device
  *
- *      Copies the scatter/gather list for the buffers that make up a packet
+ *      Generates a scatter/gather list for the buffers that make up a packet
  *      and returns the SGL size in 8-byte words.  The caller must size the SGL
  *      appropriately.
  */
-static inline unsigned int write_sgl(const struct sk_buff *skb,
+static inline unsigned int make_sgl(const struct sk_buff *skb,
                                     struct sg_ent *sgp, unsigned char *start,
-                                    unsigned int len, const dma_addr_t *addr)
+                                    unsigned int len, struct pci_dev *pdev)
 {
-        unsigned int i, j = 0, k = 0, nfrags;
+        dma_addr_t mapping;
+        unsigned int i, j = 0, nfrags;
 
         if (len) {
+                mapping = pci_map_single(pdev, start, len, PCI_DMA_TODEVICE);
                 sgp->len[0] = cpu_to_be32(len);
-                sgp->addr[j++] = cpu_to_be64(addr[k++]);
+                sgp->addr[0] = cpu_to_be64(mapping);
+                j = 1;
         }
 
         nfrags = skb_shinfo(skb)->nr_frags;
         for (i = 0; i < nfrags; i++) {
                 const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
+                mapping = skb_frag_dma_map(&pdev->dev, frag, 0, skb_frag_size(frag),
+                                           DMA_TO_DEVICE);
                 sgp->len[j] = cpu_to_be32(skb_frag_size(frag));
-                sgp->addr[j] = cpu_to_be64(addr[k++]);
+                sgp->addr[j] = cpu_to_be64(mapping);
                 j ^= 1;
                 if (j == 0)
                         ++sgp;
@@ -1178,7 +1138,7 @@ static void write_tx_pkt_wr(struct adapter *adap, struct sk_buff *skb,
                             const struct port_info *pi,
                             unsigned int pidx, unsigned int gen,
                             struct sge_txq *q, unsigned int ndesc,
-                            unsigned int compl, const dma_addr_t *addr)
+                            unsigned int compl)
 {
         unsigned int flits, sgl_flits, cntrl, tso_info;
         struct sg_ent *sgp, sgl[MAX_SKB_FRAGS / 2 + 1];
@@ -1236,7 +1196,7 @@ static void write_tx_pkt_wr(struct adapter *adap, struct sk_buff *skb,
         }
 
         sgp = ndesc == 1 ? (struct sg_ent *)&d->flit[flits] : sgl;
-        sgl_flits = write_sgl(skb, sgp, skb->data, skb_headlen(skb), addr);
+        sgl_flits = make_sgl(skb, sgp, skb->data, skb_headlen(skb), adap->pdev);
 
         write_wr_hdr_sgl(ndesc, skb, d, pidx, q, sgl, flits, sgl_flits, gen,
                          htonl(V_WR_OP(FW_WROPCODE_TUNNEL_TX_PKT) | compl),
@@ -1267,7 +1227,6 @@ netdev_tx_t t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
         struct netdev_queue *txq;
         struct sge_qset *qs;
         struct sge_txq *q;
-        dma_addr_t addr[MAX_SKB_FRAGS + 1];
 
         /*
          * The chip min packet length is 9 octets but play safe and reject
@@ -1296,11 +1255,6 @@ netdev_tx_t t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
                 return NETDEV_TX_BUSY;
         }
 
-        if (unlikely(map_skb(adap->pdev, skb, addr) < 0)) {
-                dev_kfree_skb(skb);
-                return NETDEV_TX_OK;
-        }
-
         q->in_use += ndesc;
         if (unlikely(credits - ndesc < q->stop_thres)) {
                 t3_stop_tx_queue(txq, qs, q);
@@ -1358,7 +1312,7 @@ netdev_tx_t t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
         if (likely(!skb_shared(skb)))
                 skb_orphan(skb);
 
-        write_tx_pkt_wr(adap, skb, pi, pidx, gen, q, ndesc, compl, addr);
+        write_tx_pkt_wr(adap, skb, pi, pidx, gen, q, ndesc, compl);
         check_ring_tx_db(adap, q);
         return NETDEV_TX_OK;
 }
@@ -1623,8 +1577,7 @@ static void setup_deferred_unmapping(struct sk_buff *skb, struct pci_dev *pdev,
  */
 static void write_ofld_wr(struct adapter *adap, struct sk_buff *skb,
                           struct sge_txq *q, unsigned int pidx,
-                          unsigned int gen, unsigned int ndesc,
-                          const dma_addr_t *addr)
+                          unsigned int gen, unsigned int ndesc)
 {
         unsigned int sgl_flits, flits;
         struct work_request_hdr *from;
@@ -1645,9 +1598,9 @@ static void write_ofld_wr(struct adapter *adap, struct sk_buff *skb,
 
         flits = skb_transport_offset(skb) / 8;
         sgp = ndesc == 1 ? (struct sg_ent *)&d->flit[flits] : sgl;
-        sgl_flits = write_sgl(skb, sgp, skb_transport_header(skb),
-                             skb_tail_pointer(skb) -
-                             skb_transport_header(skb), addr);
+        sgl_flits = make_sgl(skb, sgp, skb_transport_header(skb),
+                             skb->tail - skb->transport_header,
+                             adap->pdev);
         if (need_skb_unmap()) {
                 setup_deferred_unmapping(skb, adap->pdev, sgp, sgl_flits);
                 skb->destructor = deferred_unmap_destructor;
@@ -1705,11 +1658,6 @@ again:	reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
                 goto again;
         }
 
-        if (map_skb(adap->pdev, skb, (dma_addr_t *)skb->head)) {
-                spin_unlock(&q->lock);
-                return NET_XMIT_SUCCESS;
-        }
-
         gen = q->gen;
         q->in_use += ndesc;
         pidx = q->pidx;
@@ -1720,7 +1668,7 @@ again:	reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
         }
         spin_unlock(&q->lock);
 
-        write_ofld_wr(adap, skb, q, pidx, gen, ndesc, (dma_addr_t *)skb->head);
+        write_ofld_wr(adap, skb, q, pidx, gen, ndesc);
         check_ring_tx_db(adap, q);
         return NET_XMIT_SUCCESS;
 }
@@ -1738,7 +1686,6 @@ static void restart_offloadq(unsigned long data)
         struct sge_txq *q = &qs->txq[TXQ_OFLD];
         const struct port_info *pi = netdev_priv(qs->netdev);
         struct adapter *adap = pi->adapter;
-        unsigned int written = 0;
 
         spin_lock(&q->lock);
 again:  reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
@@ -1758,14 +1705,10 @@ again:	reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
                         break;
                 }
 
-                if (map_skb(adap->pdev, skb, (dma_addr_t *)skb->head))
-                        break;
-
                 gen = q->gen;
                 q->in_use += ndesc;
                 pidx = q->pidx;
                 q->pidx += ndesc;
-                written += ndesc;
                 if (q->pidx >= q->size) {
                         q->pidx -= q->size;
                         q->gen ^= 1;
@@ -1773,8 +1716,7 @@ again:	reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
                 __skb_unlink(skb, &q->sendq);
                 spin_unlock(&q->lock);
 
-                write_ofld_wr(adap, skb, q, pidx, gen, ndesc,
-                             (dma_addr_t *)skb->head);
+                write_ofld_wr(adap, skb, q, pidx, gen, ndesc);
                 spin_lock(&q->lock);
         }
         spin_unlock(&q->lock);
@@ -1784,9 +1726,8 @@ again:	reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
         set_bit(TXQ_LAST_PKT_DB, &q->flags);
 #endif
         wmb();
-        if (likely(written))
-                t3_write_reg(adap, A_SG_KDOORBELL,
-                             F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+        t3_write_reg(adap, A_SG_KDOORBELL,
+                     F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
 }
 
 /**