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i40e: xsk: add RX multi-buffer support

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This patch is inspired from the multi-buffer support in non-zc path for
i40e as well as from the patch to support zc on ice. Each subsequent
frag is added to skb_shared_info of the first frag for possible xdp_prog
use as well to xsk buffer list for accessing the buffers in af_xdp.

For XDP_PASS, new pages are allocated for frags and contents are copied
from memory backed by xsk_buff_pool.

Replace next_to_clean with next_to_process as done in non-zc path and
advance it for every buffer and change the semantics of next_to_clean to
point to the first buffer of a packet. Driver will use next_to_process
in the same way next_to_clean was used previously.

For the non multi-buffer case, next_to_process and next_to_clean will
always be the same since each packet consists of a single buffer.

Signed-off-by: Tirthendu Sarkar <tirthendu.sarkar@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-14-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Tirthendu Sarkar 2023-07-19 15:24:10 +02:00 committed by Alexei Starovoitov
parent 1bbc04de60
commit 1c9ba9c146
4 changed files with 84 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/net/ethernet/intel/i40e/i40e_main.c
View File

@ -3585,11 +3585,6 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring)
if (ring->xsk_pool) {
ring->rx_buf_len =
xsk_pool_get_rx_frame_size(ring->xsk_pool);
/* For AF_XDP ZC, we disallow packets to span on
* multiple buffers, thus letting us skip that
* handling in the fast-path.
*/
chain_len = 1;
ret = xdp_rxq_info_reg_mem_model(&ring->xdp_rxq,
MEM_TYPE_XSK_BUFF_POOL,
NULL);

4
drivers/net/ethernet/intel/i40e/i40e_txrx.c
View File

@ -2284,8 +2284,8 @@ static struct sk_buff *i40e_build_skb(struct i40e_ring *rx_ring,
* If the buffer is an EOP buffer, this function exits returning false,
* otherwise return true indicating that this is in fact a non-EOP buffer.
*/
static bool i40e_is_non_eop(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc)
bool i40e_is_non_eop(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc)
{
/* if we are the last buffer then there is nothing else to do */
#define I40E_RXD_EOF BIT(I40E_RX_DESC_STATUS_EOF_SHIFT)

2
drivers/net/ethernet/intel/i40e/i40e_txrx.h
View File

@ -473,6 +473,8 @@ int __i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size);
bool __i40e_chk_linearize(struct sk_buff *skb);
int i40e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
u32 flags);
bool i40e_is_non_eop(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc);
/**
* i40e_get_head - Retrieve head from head writeback

91
drivers/net/ethernet/intel/i40e/i40e_xsk.c
View File

@ -294,8 +294,14 @@ static struct sk_buff *i40e_construct_skb_zc(struct i40e_ring *rx_ring,
{
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);
/* allocate a skb to store the frags */
@ -312,6 +318,28 @@ static struct sk_buff *i40e_construct_skb_zc(struct i40e_ring *rx_ring,
__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;
@ -322,14 +350,13 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc,
unsigned int *rx_packets,
unsigned int *rx_bytes,
unsigned int size,
unsigned int xdp_res,
bool *failure)
{
struct sk_buff *skb;
*rx_packets = 1;
*rx_bytes = size;
*rx_bytes = xdp_get_buff_len(xdp_buff);
if (likely(xdp_res == I40E_XDP_REDIR) || xdp_res == I40E_XDP_TX)
return;
@ -363,7 +390,6 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring,
return;
}
*rx_bytes = skb->len;
i40e_process_skb_fields(rx_ring, rx_desc, skb);
napi_gro_receive(&rx_ring->q_vector->napi, skb);
return;
@ -374,6 +400,31 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring,
WARN_ON_ONCE(1);
}
static int
i40e_add_xsk_frag(struct i40e_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 (!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;
}
/**
* i40e_clean_rx_irq_zc - Consumes Rx packets from the hardware ring
* @rx_ring: Rx ring
@ -384,13 +435,18 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring,
int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
{
unsigned int total_rx_bytes = 0, total_rx_packets = 0;
u16 next_to_process = rx_ring->next_to_process;
u16 next_to_clean = rx_ring->next_to_clean;
u16 count_mask = rx_ring->count - 1;
unsigned int xdp_res, xdp_xmit = 0;
struct xdp_buff *first = NULL;
struct bpf_prog *xdp_prog;
bool failure = false;
u16 cleaned_count;
if (next_to_process != next_to_clean)
first = *i40e_rx_bi(rx_ring, next_to_clean);
/* NB! xdp_prog will always be !NULL, due to the fact that
* this path is enabled by setting an XDP program.
*/
@ -404,7 +460,7 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
unsigned int size;
u64 qword;
rx_desc = I40E_RX_DESC(rx_ring, next_to_clean);
rx_desc = I40E_RX_DESC(rx_ring, next_to_process);
qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
/* This memory barrier is needed to keep us from reading
@ -417,9 +473,9 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
i40e_clean_programming_status(rx_ring,
rx_desc->raw.qword[0],
qword);
bi = *i40e_rx_bi(rx_ring, next_to_clean);
bi = *i40e_rx_bi(rx_ring, next_to_process);
xsk_buff_free(bi);
next_to_clean = (next_to_clean + 1) & count_mask;
next_to_process = (next_to_process + 1) & count_mask;
continue;
}
@ -428,22 +484,35 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
if (!size)
break;
bi = *i40e_rx_bi(rx_ring, next_to_clean);
bi = *i40e_rx_bi(rx_ring, next_to_process);
xsk_buff_set_size(bi, size);
xsk_buff_dma_sync_for_cpu(bi, rx_ring->xsk_pool);
xdp_res = i40e_run_xdp_zc(rx_ring, bi, xdp_prog);
i40e_handle_xdp_result_zc(rx_ring, bi, rx_desc, &rx_packets,
&rx_bytes, size, xdp_res, &failure);
if (!first)
first = bi;
else if (i40e_add_xsk_frag(rx_ring, first, bi, size))
break;
next_to_process = (next_to_process + 1) & count_mask;
if (i40e_is_non_eop(rx_ring, rx_desc))
continue;
xdp_res = i40e_run_xdp_zc(rx_ring, first, xdp_prog);
i40e_handle_xdp_result_zc(rx_ring, first, rx_desc, &rx_packets,
&rx_bytes, xdp_res, &failure);
first->flags = 0;
next_to_clean = next_to_process;
if (failure)
break;
total_rx_packets += rx_packets;
total_rx_bytes += rx_bytes;
xdp_xmit |= xdp_res & (I40E_XDP_TX | I40E_XDP_REDIR);
next_to_clean = (next_to_clean + 1) & count_mask;
first = NULL;
}
rx_ring->next_to_clean = next_to_clean;
rx_ring->next_to_process = next_to_process;
cleaned_count = (next_to_clean - rx_ring->next_to_use - 1) & count_mask;
if (cleaned_count >= I40E_RX_BUFFER_WRITE)