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Message-ID: <alpine.LFD.2.11.1407020604200.15455@eddie.linux-mips.org>
Date: Sat, 5 Jul 2014 15:14:40 +0100 (BST)
From: "Maciej W. Rozycki" <macro@...ux-mips.org>
To: netdev@...r.kernel.org
cc: Robert Coerver <Robert.Coerver@...mit.edu>
Subject: [PATCH 4/5] 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@...mit.edu>
Tested-by: Robert Coerver <Robert.Coerver@...mit.edu>
Signed-off-by: Maciej W. Rozycki <macro@...ux-mips.org>
---
Please apply,
Maciej
linux-defxx-dma-map-error.patch
Index: linux-20140623-swarm64-eb/drivers/net/fddi/defxx.c
===================================================================
--- linux-20140623-swarm64-eb.orig/drivers/net/fddi/defxx.c
+++ linux-20140623-swarm64-eb/drivers/net/fddi/defxx.c
@@ -2927,21 +2927,35 @@ static int dfx_rcv_init(DFX_board_t *bp,
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.
@@ -3008,7 +3022,7 @@ 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 */
@@ -3046,15 +3060,30 @@ 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,
@@ -3062,14 +3091,10 @@ 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. */
@@ -3186,6 +3211,7 @@ static netdev_tx_t dfx_xmt_queue_pkt(str
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);
@@ -3233,6 +3259,20 @@ static netdev_tx_t dfx_xmt_queue_pkt(str
}
}
+ /* 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 */
@@ -3253,13 +3293,6 @@ static netdev_tx_t dfx_xmt_queue_pkt(str
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
*
@@ -3288,8 +3321,7 @@ static netdev_tx_t dfx_xmt_queue_pkt(str
*/
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
--
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