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gianfar: simplify FCS handling and fix memory leak

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Previously, buffer descriptors containing only the frame check sequence
(FCS) were skipped and not added to the skb. However, the page reference
count was still incremented, leading to a memory leak.

Fixing this inside gfar_add_rx_frag() is difficult due to reserved
memory handling and page reuse. Instead, move the FCS handling to
gfar_process_frame() and trim off the FCS before passing the skb up the
networking stack.

Signed-off-by: Andy Spencer <aspencer@spacex.com>
Signed-off-by: Jim Gruen <jgruen@spacex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andy Spencer 2018-02-22 11:05:33 -08:00 committed by David S. Miller
parent ca79bec237
commit d903ec7711
1 changed files with 7 additions and 16 deletions
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17
drivers/net/ethernet/freescale/gianfar.c
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@ -2934,29 +2934,17 @@ static bool gfar_add_rx_frag(struct gfar_rx_buff *rxb, u32 lstatus,
{
int size = lstatus & BD_LENGTH_MASK;
struct page *page = rxb->page;
bool last = !!(lstatus & BD_LFLAG(RXBD_LAST));
/* Remove the FCS from the packet length */
if (last)
size -= ETH_FCS_LEN;
if (likely(first)) {
skb_put(skb, size);
} else {
/* the last fragments' length contains the full frame length */
if (last)
if (lstatus & BD_LFLAG(RXBD_LAST))
size -= skb->len;
/* Add the last fragment if it contains something other than
* the FCS, otherwise drop it and trim off any part of the FCS
* that was already received.
*/
if (size > 0)
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
rxb->page_offset + RXBUF_ALIGNMENT,
size, GFAR_RXB_TRUESIZE);
else if (size < 0)
pskb_trim(skb, skb->len + size);
}
/* try reuse page */
@ -3069,6 +3057,9 @@ static void gfar_process_frame(struct net_device *ndev, struct sk_buff *skb)
if (priv->padding)
skb_pull(skb, priv->padding);
/* Trim off the FCS */
pskb_trim(skb, skb->len - ETH_FCS_LEN);
if (ndev->features & NETIF_F_RXCSUM)
gfar_rx_checksum(skb, fcb);