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gve: refactor DQO TX methods to be more generic for XDP

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This patch performs various minor DQO TX datapath refactors in
preparation for adding XDP_TX and XDP_REDIRECT support. The following
refactors are performed:

1) gve_tx_fill_pkt_desc_dqo() relies on a SKB pointer to
   get whether checksum offloading should be enabled. This won't work
   for the XDP case, which does not have a SKB. This patch updates the
   method to use a boolean representing whether checksum offloading
   should be enabled directly.

2) gve_maybe_stop_dqo() contains some synchronization between the true
   TX head and the cached value, a synchronization which is common for
   XDP queues and normal netdev queues. However, that method is reserved
   for netdev TX queues. To avoid duplicate code, this logic is factored
   out into a new method, gve_has_tx_slots_available().

3) gve_tx_update_tail() is added to update the TX tail, a functionality
   that will be common between normal TX and XDP TX codepaths.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Joshua Washington <joshwash@google.com>
Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Joshua Washington 2025-06-18 20:56:12 +00:00 committed by David S. Miller
parent d05ebf7cc3
commit cb711b3d19
1 changed files with 47 additions and 38 deletions
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85
drivers/net/ethernet/google/gve/gve_tx_dqo.c
View File

@ -439,12 +439,28 @@ static u32 num_avail_tx_slots(const struct gve_tx_ring *tx)
return tx->mask - num_used;
}
/* Checks if the requested number of slots are available in the ring */
static bool gve_has_tx_slots_available(struct gve_tx_ring *tx, u32 slots_req)
{
u32 num_avail = num_avail_tx_slots(tx);
slots_req += GVE_TX_MIN_DESC_PREVENT_CACHE_OVERLAP;
if (num_avail >= slots_req)
return true;
/* Update cached TX head pointer */
tx->dqo_tx.head = atomic_read_acquire(&tx->dqo_compl.hw_tx_head);
return num_avail_tx_slots(tx) >= slots_req;
}
static bool gve_has_avail_slots_tx_dqo(struct gve_tx_ring *tx,
int desc_count, int buf_count)
{
return gve_has_pending_packet(tx) &&
num_avail_tx_slots(tx) >= desc_count &&
gve_has_free_tx_qpl_bufs(tx, buf_count);
gve_has_tx_slots_available(tx, desc_count) &&
gve_has_free_tx_qpl_bufs(tx, buf_count);
}
/* Stops the queue if available descriptors is less than 'count'.
@ -453,12 +469,6 @@ static bool gve_has_avail_slots_tx_dqo(struct gve_tx_ring *tx,
static int gve_maybe_stop_tx_dqo(struct gve_tx_ring *tx,
int desc_count, int buf_count)
{
if (likely(gve_has_avail_slots_tx_dqo(tx, desc_count, buf_count)))
return 0;
/* Update cached TX head pointer */
tx->dqo_tx.head = atomic_read_acquire(&tx->dqo_compl.hw_tx_head);
if (likely(gve_has_avail_slots_tx_dqo(tx, desc_count, buf_count)))
return 0;
@ -472,8 +482,6 @@ static int gve_maybe_stop_tx_dqo(struct gve_tx_ring *tx,
/* After stopping queue, check if we can transmit again in order to
* avoid TOCTOU bug.
*/
tx->dqo_tx.head = atomic_read_acquire(&tx->dqo_compl.hw_tx_head);
if (likely(!gve_has_avail_slots_tx_dqo(tx, desc_count, buf_count)))
return -EBUSY;
@ -500,11 +508,9 @@ static void gve_extract_tx_metadata_dqo(const struct sk_buff *skb,
}
static void gve_tx_fill_pkt_desc_dqo(struct gve_tx_ring *tx, u32 *desc_idx,
struct sk_buff *skb, u32 len, u64 addr,
bool enable_csum, u32 len, u64 addr,
s16 compl_tag, bool eop, bool is_gso)
{
const bool checksum_offload_en = skb->ip_summed == CHECKSUM_PARTIAL;
while (len > 0) {
struct gve_tx_pkt_desc_dqo *desc =
&tx->dqo.tx_ring[*desc_idx].pkt;
@ -515,7 +521,7 @@ static void gve_tx_fill_pkt_desc_dqo(struct gve_tx_ring *tx, u32 *desc_idx,
.buf_addr = cpu_to_le64(addr),
.dtype = GVE_TX_PKT_DESC_DTYPE_DQO,
.end_of_packet = cur_eop,
.checksum_offload_enable = checksum_offload_en,
.checksum_offload_enable = enable_csum,
.compl_tag = cpu_to_le16(compl_tag),
.buf_size = cur_len,
};
@ -612,6 +618,25 @@ gve_tx_fill_general_ctx_desc(struct gve_tx_general_context_desc_dqo *desc,
};
}
static void gve_tx_update_tail(struct gve_tx_ring *tx, u32 desc_idx)
{
u32 last_desc_idx = (desc_idx - 1) & tx->mask;
u32 last_report_event_interval =
(last_desc_idx - tx->dqo_tx.last_re_idx) & tx->mask;
/* Commit the changes to our state */
tx->dqo_tx.tail = desc_idx;
/* Request a descriptor completion on the last descriptor of the
* packet if we are allowed to by the HW enforced interval.
*/
if (unlikely(last_report_event_interval >= GVE_TX_MIN_RE_INTERVAL)) {
tx->dqo.tx_ring[last_desc_idx].pkt.report_event = true;
tx->dqo_tx.last_re_idx = last_desc_idx;
}
}
static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
struct sk_buff *skb,
struct gve_tx_pending_packet_dqo *pkt,
@ -619,6 +644,7 @@ static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
u32 *desc_idx,
bool is_gso)
{
bool enable_csum = skb->ip_summed == CHECKSUM_PARTIAL;
const struct skb_shared_info *shinfo = skb_shinfo(skb);
int i;
@ -644,7 +670,7 @@ static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
dma_unmap_addr_set(pkt, dma[pkt->num_bufs], addr);
++pkt->num_bufs;
gve_tx_fill_pkt_desc_dqo(tx, desc_idx, skb, len, addr,
gve_tx_fill_pkt_desc_dqo(tx, desc_idx, enable_csum, len, addr,
completion_tag,
/*eop=*/shinfo->nr_frags == 0, is_gso);
}
@ -664,7 +690,7 @@ static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
dma[pkt->num_bufs], addr);
++pkt->num_bufs;
gve_tx_fill_pkt_desc_dqo(tx, desc_idx, skb, len, addr,
gve_tx_fill_pkt_desc_dqo(tx, desc_idx, enable_csum, len, addr,
completion_tag, is_eop, is_gso);
}
@ -709,6 +735,7 @@ static int gve_tx_add_skb_copy_dqo(struct gve_tx_ring *tx,
u32 *desc_idx,
bool is_gso)
{
bool enable_csum = skb->ip_summed == CHECKSUM_PARTIAL;
u32 copy_offset = 0;
dma_addr_t dma_addr;
u32 copy_len;
@ -730,7 +757,7 @@ static int gve_tx_add_skb_copy_dqo(struct gve_tx_ring *tx,
copy_offset += copy_len;
dma_sync_single_for_device(tx->dev, dma_addr,
copy_len, DMA_TO_DEVICE);
gve_tx_fill_pkt_desc_dqo(tx, desc_idx, skb,
gve_tx_fill_pkt_desc_dqo(tx, desc_idx, enable_csum,
copy_len,
dma_addr,
completion_tag,
@ -800,24 +827,7 @@ static int gve_tx_add_skb_dqo(struct gve_tx_ring *tx,
tx->dqo_tx.posted_packet_desc_cnt += pkt->num_bufs;
/* Commit the changes to our state */
tx->dqo_tx.tail = desc_idx;
/* Request a descriptor completion on the last descriptor of the
* packet if we are allowed to by the HW enforced interval.
*/
{
u32 last_desc_idx = (desc_idx - 1) & tx->mask;
u32 last_report_event_interval =
(last_desc_idx - tx->dqo_tx.last_re_idx) & tx->mask;
if (unlikely(last_report_event_interval >=
GVE_TX_MIN_RE_INTERVAL)) {
tx->dqo.tx_ring[last_desc_idx].pkt.report_event = true;
tx->dqo_tx.last_re_idx = last_desc_idx;
}
}
gve_tx_update_tail(tx, desc_idx);
return 0;
err:
@ -951,9 +961,8 @@ static int gve_try_tx_skb(struct gve_priv *priv, struct gve_tx_ring *tx,
/* Metadata + (optional TSO) + data descriptors. */
total_num_descs = 1 + skb_is_gso(skb) + num_buffer_descs;
if (unlikely(gve_maybe_stop_tx_dqo(tx, total_num_descs +
GVE_TX_MIN_DESC_PREVENT_CACHE_OVERLAP,
num_buffer_descs))) {
if (unlikely(gve_maybe_stop_tx_dqo(tx, total_num_descs,
num_buffer_descs))) {
return -1;
}