[PATCH 5.3 155/166] net: socionext: netsec: always grab descriptor lock

Greg Kroah-Hartman
2019-10-06T17:52:30Z

From: Lorenzo Bianconi <lorenzo@kernel.org>

[ Upstream commit 55131dec2b1c7417d216f861ea7a29dc7c4d2d20 ]

Always acquire tx descriptor spinlock even if a xdp program is not loaded
on the netsec device since ndo_xdp_xmit can run concurrently with
netsec_netdev_start_xmit and netsec_clean_tx_dring. This can happen
loading a xdp program on a different device (e.g virtio-net) and
xdp_do_redirect_map/xdp_do_redirect_slow can redirect to netsec even if
we do not have a xdp program on it.

Fixes: ba2b232108d3 ("net: netsec: add XDP support")
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/socionext/netsec.c | 30 +++++++-----------------------
1 file changed, 7 insertions(+), 23 deletions(-)

--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -282,7 +282,6 @@ struct netsec_desc_ring {
void *vaddr;
u16 head, tail;
u16 xdp_xmit; /* netsec_xdp_xmit packets */
- bool is_xdp;
struct page_pool *page_pool;
struct xdp_rxq_info xdp_rxq;
spinlock_t lock; /* XDP tx queue locking */
@@ -634,8 +633,7 @@ static bool netsec_clean_tx_dring(struct
unsigned int bytes;
int cnt = 0;

- if (dring->is_xdp)
- spin_lock(&dring->lock);
+ spin_lock(&dring->lock);

bytes = 0;
entry = dring->vaddr + DESC_SZ * tail;
@@ -682,8 +680,8 @@ next:
entry = dring->vaddr + DESC_SZ * tail;
cnt++;
}
- if (dring->is_xdp)
- spin_unlock(&dring->lock);
+
+ spin_unlock(&dring->lock);

if (!cnt)
return false;
@@ -799,9 +797,6 @@ static void netsec_set_tx_de(struct nets
de->data_buf_addr_lw = lower_32_bits(desc->dma_addr);
de->buf_len_info = (tx_ctrl->tcp_seg_len << 16) | desc->len;
de->attr = attr;
- /* under spin_lock if using XDP */
- if (!dring->is_xdp)
- dma_wmb();

dring->desc[idx] = *desc;
if (desc->buf_type == TYPE_NETSEC_SKB)
@@ -1123,12 +1118,10 @@ static netdev_tx_t netsec_netdev_start_x
u16 tso_seg_len = 0;
int filled;

- if (dring->is_xdp)
- spin_lock_bh(&dring->lock);
+ spin_lock_bh(&dring->lock);
filled = netsec_desc_used(dring);
if (netsec_check_stop_tx(priv, filled)) {
- if (dring->is_xdp)
- spin_unlock_bh(&dring->lock);
+ spin_unlock_bh(&dring->lock);
net_warn_ratelimited("%s %s Tx queue full\n",
dev_name(priv->dev), ndev->name);
return NETDEV_TX_BUSY;
@@ -1161,8 +1154,7 @@ static netdev_tx_t netsec_netdev_start_x
tx_desc.dma_addr = dma_map_single(priv->dev, skb->data,
skb_headlen(skb), DMA_TO_DEVICE);
if (dma_mapping_error(priv->dev, tx_desc.dma_addr)) {
- if (dring->is_xdp)
- spin_unlock_bh(&dring->lock);
+ spin_unlock_bh(&dring->lock);
netif_err(priv, drv, priv->ndev,
"%s: DMA mapping failed\n", __func__);
ndev->stats.tx_dropped++;
@@ -1177,8 +1169,7 @@ static netdev_tx_t netsec_netdev_start_x
netdev_sent_queue(priv->ndev, skb->len);

netsec_set_tx_de(priv, dring, &tx_ctrl, &tx_desc, skb);
- if (dring->is_xdp)
- spin_unlock_bh(&dring->lock);
+ spin_unlock_bh(&dring->lock);
netsec_write(priv, NETSEC_REG_NRM_TX_PKTCNT, 1); /* submit another tx */

return NETDEV_TX_OK;
@@ -1262,7 +1253,6 @@ err:
static void netsec_setup_tx_dring(struct netsec_priv *priv)
{
struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_TX];
- struct bpf_prog *xdp_prog = READ_ONCE(priv->xdp_prog);
int i;

for (i = 0; i < DESC_NUM; i++) {
@@ -1275,12 +1265,6 @@ static void netsec_setup_tx_dring(struct
*/
de->attr = 1U << NETSEC_TX_SHIFT_OWN_FIELD;
}
-
- if (xdp_prog)
- dring->is_xdp = true;
- else
- dring->is_xdp = false;
-
}

static int netsec_setup_rx_dring(struct netsec_priv *priv)