Re: [PATCH net-next 10/13] net: ethernet: aquantia: Checking for success dma_map_single.

[Lino Sanfilippo]

On 15.02.2017 21:01, Pavel Belous wrote:

From: Pavel Belous <pavel.bel...@aquantia.com>

Dma mapping can fail. We should check the result.

Signed-off-by: Pavel Belous <pavel.bel...@aquantia.com>
---
 drivers/net/ethernet/aquantia/atlantic/aq_nic.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_nic.c 
b/drivers/net/ethernet/aquantia/atlantic/aq_nic.c
index daed4c1..7000b9f 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_nic.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_nic.c
@@ -476,11 +476,15 @@ static unsigned int aq_nic_map_skb_frag(struct aq_nic_s 
*self,
        unsigned int ret = 0U;
        unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
        unsigned int frag_count = 0U;
+       struct device *dev = aq_nic_get_dev(self);

        dx->flags = 0U;
        dx->len = skb_headlen(skb);
-       dx->pa = dma_map_single(aq_nic_get_dev(self), skb->data, dx->len,
-                               DMA_TO_DEVICE);
+       dx->pa = dma_map_single(dev, skb->data, dx->len, DMA_TO_DEVICE);
+
+       if (unlikely(dma_mapping_error(dev, dx->pa)))
+               goto err_exit;
+
        dx->len_pkt = skb->len;
        dx->is_sop = 1U;
        dx->is_mapped = 1U;
@@ -502,8 +506,10 @@ static unsigned int aq_nic_map_skb_frag(struct aq_nic_s 
*self,

                frag_len = skb_frag_size(frag);

-               frag_pa = skb_frag_dma_map(aq_nic_get_dev(self), frag, 0,
+               frag_pa = skb_frag_dma_map(dev, frag, 0,
                                           frag_len, DMA_TO_DEVICE);
+               if (unlikely(dma_mapping_error(dev, frag_pa)))
+                       goto err_exit;

In case of this error you have to undo all mappings that you have
done so far (i.e the complete frag list and the head buffer).

                while (frag_len > AQ_CFG_TX_FRAME_MAX) {
                        ++dx;
@@ -529,6 +535,7 @@ static unsigned int aq_nic_map_skb_frag(struct aq_nic_s 
*self,
        dx->is_eop = 1U;
        dx->skb = skb;

+err_exit:
        return ret;
 }

Regards,
Lino