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net: enetc: add support for XDP_REDIRECT

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The driver implementation of the XDP_REDIRECT action reuses parts from
XDP_TX, most notably the enetc_xdp_tx function which transmits an array
of TX software BDs. Only this time, the buffers don't have DMA mappings,
we need to create them.

When a BPF program reaches the XDP_REDIRECT verdict for a frame, we can
employ the same buffer reuse strategy as for the normal processing path
and for XDP_PASS: we can flip to the other page half and seed that to
the RX ring.

Note that scatter/gather support is there, but disabled due to lack of
multi-buffer support in XDP (which is added by this series):
https://patchwork.kernel.org/project/netdevbpf/cover/cover.1616179034.git.lorenzo@kernel.org/

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vladimir Oltean 2021-03-31 23:08:57 +03:00 committed by David S. Miller
parent d6a2829e82
commit 9d2b68cc10
4 changed files with 218 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

212
drivers/net/ethernet/freescale/enetc/enetc.c
View File

@ -8,6 +8,23 @@
#include <linux/vmalloc.h>
#include <net/pkt_sched.h>
static struct sk_buff *enetc_tx_swbd_get_skb(struct enetc_tx_swbd *tx_swbd)
{
if (tx_swbd->is_xdp_tx || tx_swbd->is_xdp_redirect)
return NULL;
return tx_swbd->skb;
}
static struct xdp_frame *
enetc_tx_swbd_get_xdp_frame(struct enetc_tx_swbd *tx_swbd)
{
if (tx_swbd->is_xdp_redirect)
return tx_swbd->xdp_frame;
return NULL;
}
static void enetc_unmap_tx_buff(struct enetc_bdr *tx_ring,
struct enetc_tx_swbd *tx_swbd)
{
@ -25,14 +42,20 @@ static void enetc_unmap_tx_buff(struct enetc_bdr *tx_ring,
tx_swbd->dma = 0;
}
static void enetc_free_tx_skb(struct enetc_bdr *tx_ring,
struct enetc_tx_swbd *tx_swbd)
static void enetc_free_tx_frame(struct enetc_bdr *tx_ring,
struct enetc_tx_swbd *tx_swbd)
{
struct xdp_frame *xdp_frame = enetc_tx_swbd_get_xdp_frame(tx_swbd);
struct sk_buff *skb = enetc_tx_swbd_get_skb(tx_swbd);
if (tx_swbd->dma)
enetc_unmap_tx_buff(tx_ring, tx_swbd);
if (tx_swbd->skb) {
dev_kfree_skb_any(tx_swbd->skb);
if (xdp_frame) {
xdp_return_frame(tx_swbd->xdp_frame);
tx_swbd->xdp_frame = NULL;
} else if (skb) {
dev_kfree_skb_any(skb);
tx_swbd->skb = NULL;
}
}
@ -183,7 +206,7 @@ dma_err:
do {
tx_swbd = &tx_ring->tx_swbd[i];
enetc_free_tx_skb(tx_ring, tx_swbd);
enetc_free_tx_frame(tx_ring, tx_swbd);
if (i == 0)
i = tx_ring->bd_count;
i--;
@ -381,6 +404,9 @@ static bool enetc_clean_tx_ring(struct enetc_bdr *tx_ring, int napi_budget)
do_tstamp = false;
while (bds_to_clean && tx_frm_cnt < ENETC_DEFAULT_TX_WORK) {
struct xdp_frame *xdp_frame = enetc_tx_swbd_get_xdp_frame(tx_swbd);
struct sk_buff *skb = enetc_tx_swbd_get_skb(tx_swbd);
if (unlikely(tx_swbd->check_wb)) {
struct enetc_ndev_priv *priv = netdev_priv(ndev);
union enetc_tx_bd *txbd;
@ -400,12 +426,15 @@ static bool enetc_clean_tx_ring(struct enetc_bdr *tx_ring, int napi_budget)
else if (likely(tx_swbd->dma))
enetc_unmap_tx_buff(tx_ring, tx_swbd);
if (tx_swbd->skb) {
if (xdp_frame) {
xdp_return_frame(xdp_frame);
tx_swbd->xdp_frame = NULL;
} else if (skb) {
if (unlikely(do_tstamp)) {
enetc_tstamp_tx(tx_swbd->skb, tstamp);
enetc_tstamp_tx(skb, tstamp);
do_tstamp = false;
}
napi_consume_skb(tx_swbd->skb, napi_budget);
napi_consume_skb(skb, napi_budget);
tx_swbd->skb = NULL;
}
@ -827,6 +856,109 @@ static bool enetc_xdp_tx(struct enetc_bdr *tx_ring,
return true;
}
static int enetc_xdp_frame_to_xdp_tx_swbd(struct enetc_bdr *tx_ring,
struct enetc_tx_swbd *xdp_tx_arr,
struct xdp_frame *xdp_frame)
{
struct enetc_tx_swbd *xdp_tx_swbd = &xdp_tx_arr[0];
struct skb_shared_info *shinfo;
void *data = xdp_frame->data;
int len = xdp_frame->len;
skb_frag_t *frag;
dma_addr_t dma;
unsigned int f;
int n = 0;
dma = dma_map_single(tx_ring->dev, data, len, DMA_TO_DEVICE);
if (unlikely(dma_mapping_error(tx_ring->dev, dma))) {
netdev_err(tx_ring->ndev, "DMA map error\n");
return -1;
}
xdp_tx_swbd->dma = dma;
xdp_tx_swbd->dir = DMA_TO_DEVICE;
xdp_tx_swbd->len = len;
xdp_tx_swbd->is_xdp_redirect = true;
xdp_tx_swbd->is_eof = false;
xdp_tx_swbd->xdp_frame = NULL;
n++;
xdp_tx_swbd = &xdp_tx_arr[n];
shinfo = xdp_get_shared_info_from_frame(xdp_frame);
for (f = 0, frag = &shinfo->frags[0]; f < shinfo->nr_frags;
f++, frag++) {
data = skb_frag_address(frag);
len = skb_frag_size(frag);
dma = dma_map_single(tx_ring->dev, data, len, DMA_TO_DEVICE);
if (unlikely(dma_mapping_error(tx_ring->dev, dma))) {
/* Undo the DMA mapping for all fragments */
while (n-- >= 0)
enetc_unmap_tx_buff(tx_ring, &xdp_tx_arr[n]);
netdev_err(tx_ring->ndev, "DMA map error\n");
return -1;
}
xdp_tx_swbd->dma = dma;
xdp_tx_swbd->dir = DMA_TO_DEVICE;
xdp_tx_swbd->len = len;
xdp_tx_swbd->is_xdp_redirect = true;
xdp_tx_swbd->is_eof = false;
xdp_tx_swbd->xdp_frame = NULL;
n++;
xdp_tx_swbd = &xdp_tx_arr[n];
}
xdp_tx_arr[n - 1].is_eof = true;
xdp_tx_arr[n - 1].xdp_frame = xdp_frame;
return n;
}
int enetc_xdp_xmit(struct net_device *ndev, int num_frames,
struct xdp_frame **frames, u32 flags)
{
struct enetc_tx_swbd xdp_redirect_arr[ENETC_MAX_SKB_FRAGS] = {0};
struct enetc_ndev_priv *priv = netdev_priv(ndev);
struct enetc_bdr *tx_ring;
int xdp_tx_bd_cnt, i, k;
int xdp_tx_frm_cnt = 0;
tx_ring = priv->tx_ring[smp_processor_id()];
prefetchw(ENETC_TXBD(*tx_ring, tx_ring->next_to_use));
for (k = 0; k < num_frames; k++) {
xdp_tx_bd_cnt = enetc_xdp_frame_to_xdp_tx_swbd(tx_ring,
xdp_redirect_arr,
frames[k]);
if (unlikely(xdp_tx_bd_cnt < 0))
break;
if (unlikely(!enetc_xdp_tx(tx_ring, xdp_redirect_arr,
xdp_tx_bd_cnt))) {
for (i = 0; i < xdp_tx_bd_cnt; i++)
enetc_unmap_tx_buff(tx_ring,
&xdp_redirect_arr[i]);
tx_ring->stats.xdp_tx_drops++;
break;
}
xdp_tx_frm_cnt++;
}
if (unlikely((flags & XDP_XMIT_FLUSH) || k != xdp_tx_frm_cnt))
enetc_update_tx_ring_tail(tx_ring);
tx_ring->stats.xdp_tx += xdp_tx_frm_cnt;
return xdp_tx_frm_cnt;
}
static void enetc_map_rx_buff_to_xdp(struct enetc_bdr *rx_ring, int i,
struct xdp_buff *xdp_buff, u16 size)
{
@ -948,14 +1080,31 @@ static void enetc_xdp_drop(struct enetc_bdr *rx_ring, int rx_ring_first,
rx_ring->stats.xdp_drops++;
}
static void enetc_xdp_free(struct enetc_bdr *rx_ring, int rx_ring_first,
int rx_ring_last)
{
while (rx_ring_first != rx_ring_last) {
struct enetc_rx_swbd *rx_swbd = &rx_ring->rx_swbd[rx_ring_first];
if (rx_swbd->page) {
dma_unmap_page(rx_ring->dev, rx_swbd->dma, PAGE_SIZE,
rx_swbd->dir);
__free_page(rx_swbd->page);
rx_swbd->page = NULL;
}
enetc_bdr_idx_inc(rx_ring, &rx_ring_first);
}
rx_ring->stats.xdp_redirect_failures++;
}
static int enetc_clean_rx_ring_xdp(struct enetc_bdr *rx_ring,
struct napi_struct *napi, int work_limit,
struct bpf_prog *prog)
{
int xdp_tx_bd_cnt, xdp_tx_frm_cnt = 0, xdp_redirect_frm_cnt = 0;
struct enetc_tx_swbd xdp_tx_arr[ENETC_MAX_SKB_FRAGS] = {0};
struct enetc_ndev_priv *priv = netdev_priv(rx_ring->ndev);
struct enetc_bdr *tx_ring = priv->tx_ring[rx_ring->index];
int xdp_tx_bd_cnt, xdp_tx_frm_cnt = 0;
int rx_frm_cnt = 0, rx_byte_cnt = 0;
int cleaned_cnt, i;
u32 xdp_act;
@ -969,6 +1118,7 @@ static int enetc_clean_rx_ring_xdp(struct enetc_bdr *rx_ring,
int orig_i, orig_cleaned_cnt;
struct xdp_buff xdp_buff;
struct sk_buff *skb;
int tmp_orig_i, err;
u32 bd_status;
rxbd = enetc_rxbd(rx_ring, i);
@ -1026,6 +1176,43 @@ static int enetc_clean_rx_ring_xdp(struct enetc_bdr *rx_ring,
rx_ring->xdp.xdp_tx_in_flight += xdp_tx_bd_cnt;
xdp_tx_frm_cnt++;
}
break;
case XDP_REDIRECT:
/* xdp_return_frame does not support S/G in the sense
* that it leaks the fragments (__xdp_return should not
* call page_frag_free only for the initial buffer).
* Until XDP_REDIRECT gains support for S/G let's keep
* the code structure in place, but dead. We drop the
* S/G frames ourselves to avoid memory leaks which
* would otherwise leave the kernel OOM.
*/
if (unlikely(cleaned_cnt - orig_cleaned_cnt != 1)) {
enetc_xdp_drop(rx_ring, orig_i, i);
rx_ring->stats.xdp_redirect_sg++;
break;
}
tmp_orig_i = orig_i;
while (orig_i != i) {
enetc_put_rx_buff(rx_ring,
&rx_ring->rx_swbd[orig_i]);
enetc_bdr_idx_inc(rx_ring, &orig_i);
}
err = xdp_do_redirect(rx_ring->ndev, &xdp_buff, prog);
if (unlikely(err)) {
enetc_xdp_free(rx_ring, tmp_orig_i, i);
} else {
xdp_redirect_frm_cnt++;
rx_ring->stats.xdp_redirect++;
}
if (unlikely(xdp_redirect_frm_cnt > ENETC_DEFAULT_TX_WORK)) {
xdp_do_flush_map();
xdp_redirect_frm_cnt = 0;
}
break;
default:
bpf_warn_invalid_xdp_action(xdp_act);
@ -1039,6 +1226,9 @@ static int enetc_clean_rx_ring_xdp(struct enetc_bdr *rx_ring,
rx_ring->stats.packets += rx_frm_cnt;
rx_ring->stats.bytes += rx_byte_cnt;
if (xdp_redirect_frm_cnt)
xdp_do_flush_map();
if (xdp_tx_frm_cnt)
enetc_update_tx_ring_tail(tx_ring);
@ -1173,7 +1363,7 @@ static void enetc_free_txbdr(struct enetc_bdr *txr)
int size, i;
for (i = 0; i < txr->bd_count; i++)
enetc_free_tx_skb(txr, &txr->tx_swbd[i]);
enetc_free_tx_frame(txr, &txr->tx_swbd[i]);
size = txr->bd_count * sizeof(union enetc_tx_bd);
@ -1290,7 +1480,7 @@ static void enetc_free_tx_ring(struct enetc_bdr *tx_ring)
for (i = 0; i < tx_ring->bd_count; i++) {
struct enetc_tx_swbd *tx_swbd = &tx_ring->tx_swbd[i];
enetc_free_tx_skb(tx_ring, tx_swbd);
enetc_free_tx_frame(tx_ring, tx_swbd);
}
tx_ring->next_to_clean = 0;

11
drivers/net/ethernet/freescale/enetc/enetc.h
View File

@ -19,7 +19,10 @@
(ETH_FCS_LEN + ETH_HLEN + VLAN_HLEN))
struct enetc_tx_swbd {
struct sk_buff *skb;
union {
struct sk_buff *skb;
struct xdp_frame *xdp_frame;
};
dma_addr_t dma;
struct page *page; /* valid only if is_xdp_tx */
u16 page_offset; /* valid only if is_xdp_tx */
@ -30,6 +33,7 @@ struct enetc_tx_swbd {
u8 do_tstamp:1;
u8 is_eof:1;
u8 is_xdp_tx:1;
u8 is_xdp_redirect:1;
};
#define ENETC_RX_MAXFRM_SIZE ENETC_MAC_MAXFRM_SIZE
@ -61,6 +65,9 @@ struct enetc_ring_stats {
unsigned int xdp_drops;
unsigned int xdp_tx;
unsigned int xdp_tx_drops;
unsigned int xdp_redirect;
unsigned int xdp_redirect_failures;
unsigned int xdp_redirect_sg;
unsigned int recycles;
unsigned int recycle_failures;
};
@ -354,6 +361,8 @@ int enetc_ioctl(struct net_device *ndev, struct ifreq *rq, int cmd);
int enetc_setup_tc(struct net_device *ndev, enum tc_setup_type type,
void *type_data);
int enetc_setup_bpf(struct net_device *dev, struct netdev_bpf *xdp);
int enetc_xdp_xmit(struct net_device *ndev, int num_frames,
struct xdp_frame **frames, u32 flags);
/* ethtool */
void enetc_set_ethtool_ops(struct net_device *ndev);

6
drivers/net/ethernet/freescale/enetc/enetc_ethtool.c
View File

@ -195,6 +195,9 @@ static const char rx_ring_stats[][ETH_GSTRING_LEN] = {
"Rx ring %2d XDP drops",
"Rx ring %2d recycles",
"Rx ring %2d recycle failures",
"Rx ring %2d redirects",
"Rx ring %2d redirect failures",
"Rx ring %2d redirect S/G",
};
static const char tx_ring_stats[][ETH_GSTRING_LEN] = {
@ -284,6 +287,9 @@ static void enetc_get_ethtool_stats(struct net_device *ndev,
data[o++] = priv->rx_ring[i]->stats.xdp_drops;
data[o++] = priv->rx_ring[i]->stats.recycles;
data[o++] = priv->rx_ring[i]->stats.recycle_failures;
data[o++] = priv->rx_ring[i]->stats.xdp_redirect;
data[o++] = priv->rx_ring[i]->stats.xdp_redirect_failures;
data[o++] = priv->rx_ring[i]->stats.xdp_redirect_sg;
}
if (!enetc_si_is_pf(priv->si))

1
drivers/net/ethernet/freescale/enetc/enetc_pf.c
View File

@ -708,6 +708,7 @@ static const struct net_device_ops enetc_ndev_ops = {
.ndo_do_ioctl = enetc_ioctl,
.ndo_setup_tc = enetc_setup_tc,
.ndo_bpf = enetc_setup_bpf,
.ndo_xdp_xmit = enetc_xdp_xmit,
};
static void enetc_pf_netdev_setup(struct enetc_si *si, struct net_device *ndev,