defxx: Handle DMA mapping errors

This adds error handling for DMA mapping requests; I think there isn't
much else to say about it.

A good side-effect is the mapping in the transmit path is now made with
the board lock released.  Also if DMA mapping fails for a newly
allocated receive buffer, then data from the old buffer will be copied
out (as is presently done for small frames only whose size does not
exceed SKBUFF_RX_COPYBREAK) and the original buffer returned, with its
mapping unchanged, to the DMA descriptor ring.

Reported-by: Robert Coerver <Robert.Coerver@ll.mit.edu>
Tested-by: Robert Coerver <Robert.Coerver@ll.mit.edu>
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 58 insertions, 26 deletions

diff --git a/drivers/net/fddi/defxx.c b/drivers/net/fddi/defxx.c
index 4c5a2fe67dfb..ed23288d1c55 100644
--- a/drivers/net/fddi/defxx.c
+++ b/drivers/net/fddi/defxx.c
@@ -2923,21 +2923,35 @@ static int dfx_rcv_init(DFX_board_t *bp, int get_buffers)
         for (i = 0; i < (int)(bp->rcv_bufs_to_post); i++)
                 for (j = 0; (i + j) < (int)PI_RCV_DATA_K_NUM_ENTRIES; j += bp->rcv_bufs_to_post)
                 {
-                        struct sk_buff *newskb = __netdev_alloc_skb(bp->dev, NEW_SKB_SIZE, GFP_NOIO);
+                        struct sk_buff *newskb;
+                        dma_addr_t dma_addr;
+
+                        newskb = __netdev_alloc_skb(bp->dev, NEW_SKB_SIZE,
+                                                    GFP_NOIO);
                         if (!newskb)
                                 return -ENOMEM;
-                        bp->descr_block_virt->rcv_data[i+j].long_0 = (u32) (PI_RCV_DESCR_M_SOP |
-                                ((PI_RCV_DATA_K_SIZE_MAX / PI_ALIGN_K_RCV_DATA_BUFF) << PI_RCV_DESCR_V_SEG_LEN));
                         /*
                          * align to 128 bytes for compatibility with
                          * the old EISA boards.
                          */
 
                         my_skb_align(newskb, 128);
+                        dma_addr = dma_map_single(bp->bus_dev,
+                                                  newskb->data,
+                                                  PI_RCV_DATA_K_SIZE_MAX,
+                                                  DMA_FROM_DEVICE);
+                        if (dma_mapping_error(bp->bus_dev, dma_addr)) {
+                                dev_kfree_skb(newskb);
+                                return -ENOMEM;
+                        }
+                        bp->descr_block_virt->rcv_data[i + j].long_0 =
+                                (u32)(PI_RCV_DESCR_M_SOP |
+                                      ((PI_RCV_DATA_K_SIZE_MAX /
+                                        PI_ALIGN_K_RCV_DATA_BUFF) <<
+                                       PI_RCV_DESCR_V_SEG_LEN));
                         bp->descr_block_virt->rcv_data[i + j].long_1 =
-                                (u32)dma_map_single(bp->bus_dev, newskb->data,
-                                                    PI_RCV_DATA_K_SIZE_MAX,
-                                                    DMA_FROM_DEVICE);
+                                (u32)dma_addr;
+
                         /*
                          * p_rcv_buff_va is only used inside the
                          * kernel so we put the skb pointer here.
@@ -3004,7 +3018,7 @@ static void dfx_rcv_queue_process(
         PI_TYPE_2_CONSUMER      *p_type_2_cons;         /* ptr to rcv/xmt consumer block register */
         char                            *p_buff;                        /* ptr to start of packet receive buffer (FMC descriptor) */
         u32                                     descr, pkt_len;         /* FMC descriptor field and packet length */
-        struct sk_buff          *skb;                           /* pointer to a sk_buff to hold incoming packet data */
+        struct sk_buff          *skb = NULL;                    /* pointer to a sk_buff to hold incoming packet data */
 
         /* Service all consumed LLC receive frames */
 
@@ -3042,15 +3056,30 @@ static void dfx_rcv_queue_process(
                                 bp->rcv_length_errors++;
                         else{
 #ifdef DYNAMIC_BUFFERS
+                                struct sk_buff *newskb = NULL;
+
                                 if (pkt_len > SKBUFF_RX_COPYBREAK) {
-                                        struct sk_buff *newskb;
+                                        dma_addr_t new_dma_addr;
 
                                         newskb = netdev_alloc_skb(bp->dev,
                                                                   NEW_SKB_SIZE);
                                         if (newskb){
+                                                my_skb_align(newskb, 128);
+                                                new_dma_addr = dma_map_single(
+                                                                bp->bus_dev,
+                                                                newskb->data,
+                                                                PI_RCV_DATA_K_SIZE_MAX,
+                                                                DMA_FROM_DEVICE);
+                                                if (dma_mapping_error(
+                                                                bp->bus_dev,
+                                                                new_dma_addr)) {
+                                                        dev_kfree_skb(newskb);
+                                                        newskb = NULL;
+                                                }
+                                        }
+                                        if (newskb) {
                                                 rx_in_place = 1;
 
-                                                my_skb_align(newskb, 128);
                                                 skb = (struct sk_buff *)bp->p_rcv_buff_va[entry];
                                                 dma_unmap_single(bp->bus_dev,
                                                         bp->descr_block_virt->rcv_data[entry].long_1,
@@ -3058,14 +3087,10 @@ static void dfx_rcv_queue_process(
                                                         DMA_FROM_DEVICE);
                                                 skb_reserve(skb, RCV_BUFF_K_PADDING);
                                                 bp->p_rcv_buff_va[entry] = (char *)newskb;
-                                                bp->descr_block_virt->rcv_data[entry].long_1 =
-                                                        (u32)dma_map_single(bp->bus_dev,
-                                                                newskb->data,
-                                                                PI_RCV_DATA_K_SIZE_MAX,
-                                                                DMA_FROM_DEVICE);
-                                        } else
-                                                skb = NULL;
-                                } else
+                                                bp->descr_block_virt->rcv_data[entry].long_1 = (u32)new_dma_addr;
+                                        }
+                                }
+                                if (!newskb)
 #endif
                                         /* Alloc new buffer to pass up,
                                          * add room for PRH. */
@@ -3185,6 +3210,7 @@ static netdev_tx_t dfx_xmt_queue_pkt(struct sk_buff *skb,
         u8                      prod;                           /* local transmit producer index */
         PI_XMT_DESCR            *p_xmt_descr;           /* ptr to transmit descriptor block entry */
         XMT_DRIVER_DESCR        *p_xmt_drv_descr;       /* ptr to transmit driver descriptor */
+        dma_addr_t              dma_addr;
         unsigned long           flags;
 
         netif_stop_queue(dev);
@@ -3232,6 +3258,20 @@ static netdev_tx_t dfx_xmt_queue_pkt(struct sk_buff *skb,
                         }
                 }
 
+        /* Write the three PRH bytes immediately before the FC byte */
+
+        skb_push(skb, 3);
+        skb->data[0] = DFX_PRH0_BYTE;   /* these byte values are defined */
+        skb->data[1] = DFX_PRH1_BYTE;   /* in the Motorola FDDI MAC chip */
+        skb->data[2] = DFX_PRH2_BYTE;   /* specification */
+
+        dma_addr = dma_map_single(bp->bus_dev, skb->data, skb->len,
+                                  DMA_TO_DEVICE);
+        if (dma_mapping_error(bp->bus_dev, dma_addr)) {
+                skb_pull(skb, 3);
+                return NETDEV_TX_BUSY;
+        }
+
         spin_lock_irqsave(&bp->lock, flags);
 
         /* Get the current producer and the next free xmt data descriptor */
@@ -3252,13 +3292,6 @@ static netdev_tx_t dfx_xmt_queue_pkt(struct sk_buff *skb,
 
         p_xmt_drv_descr = &(bp->xmt_drv_descr_blk[prod++]);     /* also bump producer index */
 
-        /* Write the three PRH bytes immediately before the FC byte */
-
-        skb_push(skb,3);
-        skb->data[0] = DFX_PRH0_BYTE;   /* these byte values are defined */
-        skb->data[1] = DFX_PRH1_BYTE;   /* in the Motorola FDDI MAC chip */
-        skb->data[2] = DFX_PRH2_BYTE;   /* specification */
-
         /*
          * Write the descriptor with buffer info and bump producer
          *
@@ -3287,8 +3320,7 @@ static netdev_tx_t dfx_xmt_queue_pkt(struct sk_buff *skb,
          */
 
         p_xmt_descr->long_0     = (u32) (PI_XMT_DESCR_M_SOP | PI_XMT_DESCR_M_EOP | ((skb->len) << PI_XMT_DESCR_V_SEG_LEN));
-        p_xmt_descr->long_1 = (u32)dma_map_single(bp->bus_dev, skb->data,
-                                                  skb->len, DMA_TO_DEVICE);
+        p_xmt_descr->long_1 = (u32)dma_addr;
 
         /*
          * Verify that descriptor is actually available