[PATCH 4.16 228/272] dpaa_eth: fix SG mapping

Greg Kroah-Hartman
2018-05-28T11:14:31Z

From: Madalin Bucur <madalin.bucur@nxp.com>

[ Upstream commit 120d75ecf043044554abbba8507f6d22e4715beb ]

An issue in the code mapping the skb fragments into
scatter-gather frames was evidentiated by netperf
TCP_SENDFILE tests. The size was set wrong for all
fragments but the first, affecting the transmission
of any skb with more than one fragment.

Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)

--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -1916,8 +1916,10 @@ static int skb_to_sg_fd(struct dpaa_priv
goto csum_failed;
}

+ /* SGT[0] is used by the linear part */
sgt = (struct qm_sg_entry *)(sgt_buf + priv->tx_headroom);
- qm_sg_entry_set_len(&sgt[0], skb_headlen(skb));
+ frag_len = skb_headlen(skb);
+ qm_sg_entry_set_len(&sgt[0], frag_len);
sgt[0].bpid = FSL_DPAA_BPID_INV;
sgt[0].offset = 0;
addr = dma_map_single(dev, skb->data,
@@ -1930,9 +1932,9 @@ static int skb_to_sg_fd(struct dpaa_priv
qm_sg_entry_set64(&sgt[0], addr);

/* populate the rest of SGT entries */
- frag = &skb_shinfo(skb)->frags[0];
- frag_len = frag->size;
- for (i = 1; i <= nr_frags; i++, frag++) {
+ for (i = 0; i < nr_frags; i++) {
+ frag = &skb_shinfo(skb)->frags[i];
+ frag_len = frag->size;
WARN_ON(!skb_frag_page(frag));
addr = skb_frag_dma_map(dev, frag, 0,
frag_len, dma_dir);
@@ -1942,15 +1944,16 @@ static int skb_to_sg_fd(struct dpaa_priv
goto sg_map_failed;
}

- qm_sg_entry_set_len(&sgt[i], frag_len);
- sgt[i].bpid = FSL_DPAA_BPID_INV;
- sgt[i].offset = 0;
+ qm_sg_entry_set_len(&sgt[i + 1], frag_len);
+ sgt[i + 1].bpid = FSL_DPAA_BPID_INV;
+ sgt[i + 1].offset = 0;

/* keep the offset in the address */
- qm_sg_entry_set64(&sgt[i], addr);
- frag_len = frag->size;
+ qm_sg_entry_set64(&sgt[i + 1], addr);
}
- qm_sg_entry_set_f(&sgt[i - 1], frag_len);
+
+ /* Set the final bit in the last used entry of the SGT */
+ qm_sg_entry_set_f(&sgt[nr_frags], frag_len);

qm_fd_set_sg(fd, priv->tx_headroom, skb->len);