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ice: xsk: add RX multi-buffer support

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This support is strongly inspired by work that introduced multi-buffer
support to regular Rx data path in ice. There are some differences,
though. When adding a frag, besides adding it to skb_shared_info, use
also fresh xsk_buff_add_frag() helper. Reason for doing both things is
that we can not rule out the fact that AF_XDP pipeline could use XDP
program that needs to access frame fragments. Without them being in
skb_shared_info it will not be possible. Another difference is that
XDP_PASS has to allocate a new pages for each frags and copy contents
from memory backed by xsk_buff_pool.

chain_len that is used for programming HW Rx descriptors no longer has
to be limited to 1 when xsk_pool is present - remove this restriction.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-13-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Maciej Fijalkowski 2023-07-19 15:24:09 +02:00 committed by Alexei Starovoitov
parent 24ea50127e
commit 1bbc04de60
2 changed files with 102 additions and 43 deletions
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9
drivers/net/ethernet/intel/ice/ice_base.c
View file

@ -408,7 +408,6 @@ static unsigned int ice_rx_offset(struct ice_rx_ring *rx_ring)
*/
static int ice_setup_rx_ctx(struct ice_rx_ring *ring)
{
int chain_len = ICE_MAX_CHAINED_RX_BUFS;
struct ice_vsi *vsi = ring->vsi;
u32 rxdid = ICE_RXDID_FLEX_NIC;
struct ice_rlan_ctx rlan_ctx;
@ -472,17 +471,11 @@ static int ice_setup_rx_ctx(struct ice_rx_ring *ring)
*/
rlan_ctx.showiv = 0;
/* For AF_XDP ZC, we disallow packets to span on
* multiple buffers, thus letting us skip that
* handling in the fast-path.
*/
if (ring->xsk_pool)
chain_len = 1;
/* Max packet size for this queue - must not be set to a larger value
* than 5 x DBUF
*/
rlan_ctx.rxmax = min_t(u32, vsi->max_frame,
chain_len * ring->rx_buf_len);
ICE_MAX_CHAINED_RX_BUFS * ring->rx_buf_len);
/* Rx queue threshold in units of 64 */
rlan_ctx.lrxqthresh = 1;

136
drivers/net/ethernet/intel/ice/ice_xsk.c
View file

@ -545,19 +545,6 @@ bool ice_alloc_rx_bufs_zc(struct ice_rx_ring *rx_ring, u16 count)
return __ice_alloc_rx_bufs_zc(rx_ring, leftover);
}
/**
* ice_bump_ntc - Bump the next_to_clean counter of an Rx ring
* @rx_ring: Rx ring
*/
static void ice_bump_ntc(struct ice_rx_ring *rx_ring)
{
int ntc = rx_ring->next_to_clean + 1;
ntc = (ntc < rx_ring->count) ? ntc : 0;
rx_ring->next_to_clean = ntc;
prefetch(ICE_RX_DESC(rx_ring, ntc));
}
/**
* ice_construct_skb_zc - Create an sk_buff from zero-copy buffer
* @rx_ring: Rx ring
@ -572,8 +559,14 @@ ice_construct_skb_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp)
{
unsigned int totalsize = xdp->data_end - xdp->data_meta;
unsigned int metasize = xdp->data - xdp->data_meta;
struct skb_shared_info *sinfo = NULL;
struct sk_buff *skb;
u32 nr_frags = 0;
if (unlikely(xdp_buff_has_frags(xdp))) {
sinfo = xdp_get_shared_info_from_buff(xdp);
nr_frags = sinfo->nr_frags;
}
net_prefetch(xdp->data_meta);
skb = __napi_alloc_skb(&rx_ring->q_vector->napi, totalsize,
@ -589,6 +582,29 @@ ice_construct_skb_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp)
__skb_pull(skb, metasize);
}
if (likely(!xdp_buff_has_frags(xdp)))
goto out;
for (int i = 0; i < nr_frags; i++) {
struct skb_shared_info *skinfo = skb_shinfo(skb);
skb_frag_t *frag = &sinfo->frags[i];
struct page *page;
void *addr;
page = dev_alloc_page();
if (!page) {
dev_kfree_skb(skb);
return NULL;
}
addr = page_to_virt(page);
memcpy(addr, skb_frag_page(frag), skb_frag_size(frag));
__skb_fill_page_desc_noacc(skinfo, skinfo->nr_frags++,
addr, 0, skb_frag_size(frag));
}
out:
xsk_buff_free(xdp);
return skb;
}
@ -752,6 +768,34 @@ ice_run_xdp_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
return result;
}
static int
ice_add_xsk_frag(struct ice_rx_ring *rx_ring, struct xdp_buff *first,
struct xdp_buff *xdp, const unsigned int size)
{
struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(first);
if (!size)
return 0;
if (!xdp_buff_has_frags(first)) {
sinfo->nr_frags = 0;
sinfo->xdp_frags_size = 0;
xdp_buff_set_frags_flag(first);
}
if (unlikely(sinfo->nr_frags == MAX_SKB_FRAGS)) {
xsk_buff_free(first);
return -ENOMEM;
}
__skb_fill_page_desc_noacc(sinfo, sinfo->nr_frags++,
virt_to_page(xdp->data_hard_start), 0, size);
sinfo->xdp_frags_size += size;
xsk_buff_add_frag(xdp);
return 0;
}
/**
* ice_clean_rx_irq_zc - consumes packets from the hardware ring
* @rx_ring: AF_XDP Rx ring
@ -762,9 +806,14 @@ ice_run_xdp_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
{
unsigned int total_rx_bytes = 0, total_rx_packets = 0;
struct xsk_buff_pool *xsk_pool = rx_ring->xsk_pool;
u32 ntc = rx_ring->next_to_clean;
u32 ntu = rx_ring->next_to_use;
struct xdp_buff *first = NULL;
struct ice_tx_ring *xdp_ring;
unsigned int xdp_xmit = 0;
struct bpf_prog *xdp_prog;
u32 cnt = rx_ring->count;
bool failure = false;
int entries_to_alloc;
@ -774,6 +823,9 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
xdp_prog = READ_ONCE(rx_ring->xdp_prog);
xdp_ring = rx_ring->xdp_ring;
if (ntc != rx_ring->first_desc)
first = *ice_xdp_buf(rx_ring, rx_ring->first_desc);
while (likely(total_rx_packets < (unsigned int)budget)) {
union ice_32b_rx_flex_desc *rx_desc;
unsigned int size, xdp_res = 0;
@ -783,7 +835,7 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
u16 vlan_tag = 0;
u16 rx_ptype;
rx_desc = ICE_RX_DESC(rx_ring, rx_ring->next_to_clean);
rx_desc = ICE_RX_DESC(rx_ring, ntc);
stat_err_bits = BIT(ICE_RX_FLEX_DESC_STATUS0_DD_S);
if (!ice_test_staterr(rx_desc->wb.status_error0, stat_err_bits))
@ -795,51 +847,61 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
*/
dma_rmb();
if (unlikely(rx_ring->next_to_clean == rx_ring->next_to_use))
if (unlikely(ntc == ntu))
break;
xdp = *ice_xdp_buf(rx_ring, rx_ring->next_to_clean);
xdp = *ice_xdp_buf(rx_ring, ntc);
size = le16_to_cpu(rx_desc->wb.pkt_len) &
ICE_RX_FLX_DESC_PKT_LEN_M;
if (!size) {
xdp->data = NULL;
xdp->data_end = NULL;
xdp->data_hard_start = NULL;
xdp->data_meta = NULL;
goto construct_skb;
}
xsk_buff_set_size(xdp, size);
xsk_buff_dma_sync_for_cpu(xdp, rx_ring->xsk_pool);
xsk_buff_dma_sync_for_cpu(xdp, xsk_pool);
xdp_res = ice_run_xdp_zc(rx_ring, xdp, xdp_prog, xdp_ring);
if (!first) {
first = xdp;
xdp_buff_clear_frags_flag(first);
} else if (ice_add_xsk_frag(rx_ring, first, xdp, size)) {
break;
}
if (++ntc == cnt)
ntc = 0;
if (ice_is_non_eop(rx_ring, rx_desc))
continue;
xdp_res = ice_run_xdp_zc(rx_ring, first, xdp_prog, xdp_ring);
if (likely(xdp_res & (ICE_XDP_TX | ICE_XDP_REDIR))) {
xdp_xmit |= xdp_res;
} else if (xdp_res == ICE_XDP_EXIT) {
failure = true;
first = NULL;
rx_ring->first_desc = ntc;
break;
} else if (xdp_res == ICE_XDP_CONSUMED) {
xsk_buff_free(xdp);
xsk_buff_free(first);
} else if (xdp_res == ICE_XDP_PASS) {
goto construct_skb;
}
total_rx_bytes += size;
total_rx_bytes += xdp_get_buff_len(first);
total_rx_packets++;
ice_bump_ntc(rx_ring);
first = NULL;
rx_ring->first_desc = ntc;
continue;
construct_skb:
/* XDP_PASS path */
skb = ice_construct_skb_zc(rx_ring, xdp);
skb = ice_construct_skb_zc(rx_ring, first);
if (!skb) {
rx_ring->ring_stats->rx_stats.alloc_buf_failed++;
break;
}
ice_bump_ntc(rx_ring);
first = NULL;
rx_ring->first_desc = ntc;
if (eth_skb_pad(skb)) {
skb = NULL;
@ -858,18 +920,22 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
ice_receive_skb(rx_ring, skb, vlan_tag);
}
entries_to_alloc = ICE_DESC_UNUSED(rx_ring);
rx_ring->next_to_clean = ntc;
entries_to_alloc = ICE_RX_DESC_UNUSED(rx_ring);
if (entries_to_alloc > ICE_RING_QUARTER(rx_ring))
failure |= !ice_alloc_rx_bufs_zc(rx_ring, entries_to_alloc);
ice_finalize_xdp_rx(xdp_ring, xdp_xmit, 0);
ice_update_rx_ring_stats(rx_ring, total_rx_packets, total_rx_bytes);
if (xsk_uses_need_wakeup(rx_ring->xsk_pool)) {
if (failure || rx_ring->next_to_clean == rx_ring->next_to_use)
xsk_set_rx_need_wakeup(rx_ring->xsk_pool);
if (xsk_uses_need_wakeup(xsk_pool)) {
/* ntu could have changed when allocating entries above, so
* use rx_ring value instead of stack based one
*/
if (failure || ntc == rx_ring->next_to_use)
xsk_set_rx_need_wakeup(xsk_pool);
else
xsk_clear_rx_need_wakeup(rx_ring->xsk_pool);
xsk_clear_rx_need_wakeup(xsk_pool);
return (int)total_rx_packets;
}