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ionic: refactor skb building
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The existing ionic_rx_frags() code is a bit of a mess and can
be cleaned up by unrolling the first frag/header setup from
the loop, then reworking the do-while-loop into a for-loop.  We
rename the function to a more descriptive ionic_rx_build_skb().
We also change a couple of related variable names for readability.

Reviewed-by: Brett Creeley <[email protected]>
Signed-off-by: Shannon Nelson <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@emusln @davem330
emusln authored and davem330 committed Mar 8, 2024
1 parent 8599bd4 commit 36a47c9
Showing 1 changed file with 65 additions and 53 deletions.
118 changes: 65 additions & 53 deletions drivers/net/ethernet/pensando/ionic/ionic_txrx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -185,7 +185,7 @@ static void ionic_rx_page_free(struct ionic_queue *q,
}

static bool ionic_rx_buf_recycle(struct ionic_queue *q,
struct ionic_buf_info *buf_info, u32 used)
struct ionic_buf_info *buf_info, u32 len)
{
u32 size;

Expand All @@ -197,7 +197,7 @@ static bool ionic_rx_buf_recycle(struct ionic_queue *q,
if (page_to_nid(buf_info->page) != numa_mem_id())
return false;

size = ALIGN(used, q->xdp_rxq_info ? IONIC_PAGE_SIZE : IONIC_PAGE_SPLIT_SZ);
size = ALIGN(len, q->xdp_rxq_info ? IONIC_PAGE_SIZE : IONIC_PAGE_SPLIT_SZ);
buf_info->page_offset += size;
if (buf_info->page_offset >= IONIC_PAGE_SIZE)
return false;
Expand All @@ -207,72 +207,79 @@ static bool ionic_rx_buf_recycle(struct ionic_queue *q,
return true;
}

static struct sk_buff *ionic_rx_frags(struct net_device *netdev,
struct ionic_queue *q,
struct ionic_rx_desc_info *desc_info,
unsigned int headroom,
unsigned int len,
unsigned int num_sg_elems,
bool synced)
static void ionic_rx_add_skb_frag(struct ionic_queue *q,
struct sk_buff *skb,
struct ionic_buf_info *buf_info,
u32 off, u32 len,
bool synced)
{
if (!synced)
dma_sync_single_range_for_cpu(q->dev, ionic_rx_buf_pa(buf_info),
off, len, DMA_FROM_DEVICE);

skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
buf_info->page, buf_info->page_offset + off,
len,
IONIC_PAGE_SIZE);

if (!ionic_rx_buf_recycle(q, buf_info, len)) {
dma_unmap_page(q->dev, buf_info->dma_addr,
IONIC_PAGE_SIZE, DMA_FROM_DEVICE);
buf_info->page = NULL;
}
}

static struct sk_buff *ionic_rx_build_skb(struct ionic_queue *q,
struct ionic_rx_desc_info *desc_info,
unsigned int headroom,
unsigned int len,
unsigned int num_sg_elems,
bool synced)
{
struct ionic_buf_info *buf_info;
struct ionic_rx_stats *stats;
struct device *dev = q->dev;
struct sk_buff *skb;
unsigned int i;
u16 frag_len;

stats = q_to_rx_stats(q);

buf_info = &desc_info->bufs[0];

prefetchw(buf_info->page);

skb = napi_get_frags(&q_to_qcq(q)->napi);
if (unlikely(!skb)) {
net_warn_ratelimited("%s: SKB alloc failed on %s!\n",
dev_name(dev), q->name);
dev_name(q->dev), q->name);
stats->alloc_err++;
return NULL;
}

i = num_sg_elems + 1;
do {
if (unlikely(!buf_info->page)) {
dev_kfree_skb(skb);
return NULL;
}

if (headroom)
frag_len = min_t(u16, len, IONIC_XDP_MAX_LINEAR_MTU + VLAN_ETH_HLEN);
else
frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));
len -= frag_len;

if (!synced)
dma_sync_single_range_for_cpu(dev, ionic_rx_buf_pa(buf_info),
headroom, frag_len, DMA_FROM_DEVICE);

skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
buf_info->page, buf_info->page_offset + headroom,
frag_len, IONIC_PAGE_SIZE);

if (!ionic_rx_buf_recycle(q, buf_info, frag_len)) {
dma_unmap_page(dev, buf_info->dma_addr,
IONIC_PAGE_SIZE, DMA_FROM_DEVICE);
buf_info->page = NULL;
}

/* only needed on the first buffer */
if (headroom)
headroom = 0;
if (headroom)
frag_len = min_t(u16, len,
IONIC_XDP_MAX_LINEAR_MTU + VLAN_ETH_HLEN);
else
frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));

buf_info++;
if (unlikely(!buf_info->page))
goto err_bad_buf_page;
ionic_rx_add_skb_frag(q, skb, buf_info, headroom, frag_len, synced);
len -= frag_len;
buf_info++;

i--;
} while (i > 0);
for (i = 0; i < num_sg_elems; i++, buf_info++) {
if (unlikely(!buf_info->page))
goto err_bad_buf_page;
frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));
ionic_rx_add_skb_frag(q, skb, buf_info, 0, frag_len, synced);
len -= frag_len;
}

return skb;

err_bad_buf_page:
dev_kfree_skb(skb);
return NULL;
}

static struct sk_buff *ionic_rx_copybreak(struct net_device *netdev,
Expand Down Expand Up @@ -641,6 +648,8 @@ static void ionic_rx_clean(struct ionic_queue *q,
struct bpf_prog *xdp_prog;
unsigned int headroom;
struct sk_buff *skb;
bool synced = false;
bool use_copybreak;
u16 len;

stats = q_to_rx_stats(q);
Expand All @@ -655,17 +664,20 @@ static void ionic_rx_clean(struct ionic_queue *q,
stats->bytes += len;

xdp_prog = READ_ONCE(q->lif->xdp_prog);
if (xdp_prog &&
ionic_run_xdp(stats, netdev, xdp_prog, q, desc_info->bufs, len))
return;
if (xdp_prog) {
if (ionic_run_xdp(stats, netdev, xdp_prog, q, desc_info->bufs, len))
return;
synced = true;
}

headroom = q->xdp_rxq_info ? XDP_PACKET_HEADROOM : 0;
if (len <= q->lif->rx_copybreak)
use_copybreak = len <= q->lif->rx_copybreak;
if (use_copybreak)
skb = ionic_rx_copybreak(netdev, q, desc_info,
headroom, len, !!xdp_prog);
headroom, len, synced);
else
skb = ionic_rx_frags(netdev, q, desc_info, headroom, len,
comp->num_sg_elems, !!xdp_prog);
skb = ionic_rx_build_skb(q, desc_info, headroom, len,
comp->num_sg_elems, synced);

if (unlikely(!skb)) {
stats->dropped++;
Expand Down Expand Up @@ -732,7 +744,7 @@ static void ionic_rx_clean(struct ionic_queue *q,
}
}

if (len <= q->lif->rx_copybreak)
if (use_copybreak)
napi_gro_receive(&qcq->napi, skb);
else
napi_gro_frags(&qcq->napi);
Expand Down

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