/**
* efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
* @tx_queue: Efx TX queue
* @skb: Socket buffer
*
* Context: You must hold netif_tx_lock() to call this function.
*
* Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
* @skb was not enqueued. In all cases @skb is consumed. Return
* %NETDEV_TX_OK or %NETDEV_TX_BUSY.
*/
static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
struct sk_buff *skb)
{
struct efx_nic *efx = tx_queue->efx;
int frag_i, rc, rc2 = NETDEV_TX_OK;
struct tso_state state;
/* Find the packet protocol and sanity-check it */
state.protocol = efx_tso_check_protocol(skb);
EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
tso_start(&state, skb);
/* Assume that skb header area contains exactly the headers, and
* all payload is in the frag list.
*/
if (skb_headlen(skb) == state.header_len) {
/* Grab the first payload fragment. */
EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1);
frag_i = 0;
rc = tso_get_fragment(&state, efx,
skb_shinfo(skb)->frags + frag_i);
if (rc)
goto mem_err;
} else {
rc = tso_get_head_fragment(&state, efx, skb);
if (rc)
goto mem_err;
frag_i = -1;
}
if (tso_start_new_packet(tx_queue, skb, &state) < 0)
goto mem_err;
while (1) {
rc = tso_fill_packet_with_fragment(tx_queue, skb, &state);
if (unlikely(rc)) {
rc2 = NETDEV_TX_BUSY;
goto unwind;
}
/* Move onto the next fragment? */
if (state.in_len == 0) {
if (++frag_i >= skb_shinfo(skb)->nr_frags)
/* End of payload reached. */
break;
rc = tso_get_fragment(&state, efx,
skb_shinfo(skb)->frags + frag_i);
if (rc)
goto mem_err;
}
/* Start at new packet? */
if (state.packet_space == 0 &&
tso_start_new_packet(tx_queue, skb, &state) < 0)
goto mem_err;
}
/* Pass off to hardware */
efx_nic_push_buffers(tx_queue);
tx_queue->tso_bursts++;
return NETDEV_TX_OK;
mem_err:
netif_err(efx, tx_err, efx->net_dev,
"Out of memory for TSO headers, or PCI mapping error\n");
dev_kfree_skb_any(skb);
unwind:
/* Free the DMA mapping we were in the process of writing out */
if (state.unmap_len) {
if (state.unmap_single)
pci_unmap_single(efx->pci_dev, state.unmap_addr,
state.unmap_len, PCI_DMA_TODEVICE);
else
pci_unmap_page(efx->pci_dev, state.unmap_addr,
state.unmap_len, PCI_DMA_TODEVICE);
}
efx_enqueue_unwind(tx_queue);
return rc2;
}
/*
* Add a socket buffer to a TX queue
*
* This maps all fragments of a socket buffer for DMA and adds them to
* the TX queue. The queue's insert pointer will be incremented by
* the number of fragments in the socket buffer.
*
* If any DMA mapping fails, any mapped fragments will be unmapped,
* the queue's insert pointer will be restored to its original value.
*
* This function is split out from efx_hard_start_xmit to allow the
* loopback test to direct packets via specific TX queues.
*
* Returns NETDEV_TX_OK or NETDEV_TX_BUSY
* You must hold netif_tx_lock() to call this function.
*/
netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
{
struct efx_nic *efx = tx_queue->efx;
struct pci_dev *pci_dev = efx->pci_dev;
struct efx_tx_buffer *buffer;
skb_frag_t *fragment;
struct page *page;
int page_offset;
unsigned int len, unmap_len = 0, fill_level, insert_ptr;
dma_addr_t dma_addr, unmap_addr = 0;
unsigned int dma_len;
bool unmap_single;
int q_space, i = 0;
netdev_tx_t rc = NETDEV_TX_OK;
EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
if (skb_shinfo(skb)->gso_size)
return efx_enqueue_skb_tso(tx_queue, skb);
/* Get size of the initial fragment */
len = skb_headlen(skb);
/* Pad if necessary */
if (EFX_WORKAROUND_15592(efx) && skb->len <= 32) {
EFX_BUG_ON_PARANOID(skb->data_len);
len = 32 + 1;
if (skb_pad(skb, len - skb->len))
return NETDEV_TX_OK;
}
fill_level = tx_queue->insert_count - tx_queue->old_read_count;
q_space = efx->txq_entries - 1 - fill_level;
/* Map for DMA. Use pci_map_single rather than pci_map_page
* since this is more efficient on machines with sparse
* memory.
*/
unmap_single = true;
dma_addr = pci_map_single(pci_dev, skb->data, len, PCI_DMA_TODEVICE);
/* Process all fragments */
while (1) {
if (unlikely(pci_dma_mapping_error(pci_dev, dma_addr)))
goto pci_err;
/* Store fields for marking in the per-fragment final
* descriptor */
unmap_len = len;
unmap_addr = dma_addr;
/* Add to TX queue, splitting across DMA boundaries */
do {
if (unlikely(q_space-- <= 0)) {
/* It might be that completions have
* happened since the xmit path last
* checked. Update the xmit path's
* copy of read_count.
*/
netif_tx_stop_queue(tx_queue->core_txq);
/* This memory barrier protects the
* change of queue state from the access
* of read_count. */
smp_mb();
tx_queue->old_read_count =
ACCESS_ONCE(tx_queue->read_count);
fill_level = (tx_queue->insert_count
- tx_queue->old_read_count);
q_space = efx->txq_entries - 1 - fill_level;
if (unlikely(q_space-- <= 0)) {
rc = NETDEV_TX_BUSY;
goto unwind;
}
smp_mb();
netif_tx_start_queue(tx_queue->core_txq);
}
insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
buffer = &tx_queue->buffer[insert_ptr];
efx_tsoh_free(tx_queue, buffer);
EFX_BUG_ON_PARANOID(buffer->tsoh);
EFX_BUG_ON_PARANOID(buffer->skb);
EFX_BUG_ON_PARANOID(buffer->len);
EFX_BUG_ON_PARANOID(!buffer->continuation);
EFX_BUG_ON_PARANOID(buffer->unmap_len);
dma_len = efx_max_tx_len(efx, dma_addr);
if (likely(dma_len >= len))
dma_len = len;
/* Fill out per descriptor fields */
buffer->len = dma_len;
buffer->dma_addr = dma_addr;
len -= dma_len;
dma_addr += dma_len;
++tx_queue->insert_count;
} while (len);
/* Transfer ownership of the unmapping to the final buffer */
buffer->unmap_single = unmap_single;
buffer->unmap_len = unmap_len;
unmap_len = 0;
/* Get address and size of next fragment */
if (i >= skb_shinfo(skb)->nr_frags)
break;
fragment = &skb_shinfo(skb)->frags[i];
len = fragment->size;
page = fragment->page;
page_offset = fragment->page_offset;
i++;
/* Map for DMA */
unmap_single = false;
dma_addr = pci_map_page(pci_dev, page, page_offset, len,
PCI_DMA_TODEVICE);
}
/* Transfer ownership of the skb to the final buffer */
buffer->skb = skb;
buffer->continuation = false;
/* Pass off to hardware */
efx_nic_push_buffers(tx_queue);
return NETDEV_TX_OK;
pci_err:
netif_err(efx, tx_err, efx->net_dev,
" TX queue %d could not map skb with %d bytes %d "
"fragments for DMA\n", tx_queue->queue, skb->len,
skb_shinfo(skb)->nr_frags + 1);
/* Mark the packet as transmitted, and free the SKB ourselves */
dev_kfree_skb_any(skb);
unwind:
/* Work backwards until we hit the original insert pointer value */
while (tx_queue->insert_count != tx_queue->write_count) {
--tx_queue->insert_count;
insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
buffer = &tx_queue->buffer[insert_ptr];
efx_dequeue_buffer(tx_queue, buffer);
buffer->len = 0;
}
/* Free the fragment we were mid-way through pushing */
if (unmap_len) {
if (unmap_single)
pci_unmap_single(pci_dev, unmap_addr, unmap_len,
PCI_DMA_TODEVICE);
else
pci_unmap_page(pci_dev, unmap_addr, unmap_len,
PCI_DMA_TODEVICE);
}
return rc;
}
/**
* efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
* @tx_queue: Efx TX queue
* @skb: Socket buffer
*
* Context: You must hold netif_tx_lock() to call this function.
*
* Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
* @skb was not enqueued. In all cases @skb is consumed. Return
* %NETDEV_TX_OK or %NETDEV_TX_BUSY.
*/
static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
struct sk_buff *skb)
{
struct efx_nic *efx = tx_queue->efx;
int frag_i, rc, rc2 = NETDEV_TX_OK;
struct tso_state state;
/* Since the stack does not limit the number of segments per
* skb, we must do so. Otherwise an attacker may be able to
* make the TCP produce skbs that will never fit in our TX
* queue, causing repeated resets.
*/
if (unlikely(skb_shinfo(skb)->gso_segs > EFX_TSO_MAX_SEGS)) {
unsigned int excess =
(skb_shinfo(skb)->gso_segs - EFX_TSO_MAX_SEGS) *
skb_shinfo(skb)->gso_size;
if (__pskb_trim(skb, skb->len - excess)) {
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}
}
/* Find the packet protocol and sanity-check it */
state.protocol = efx_tso_check_protocol(skb);
EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
tso_start(&state, skb);
/* Assume that skb header area contains exactly the headers, and
* all payload is in the frag list.
*/
if (skb_headlen(skb) == state.header_len) {
/* Grab the first payload fragment. */
EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1);
frag_i = 0;
rc = tso_get_fragment(&state, efx,
skb_shinfo(skb)->frags + frag_i);
if (rc)
goto mem_err;
} else {
rc = tso_get_head_fragment(&state, efx, skb);
if (rc)
goto mem_err;
frag_i = -1;
}
if (tso_start_new_packet(tx_queue, skb, &state) < 0)
goto mem_err;
while (1) {
rc = tso_fill_packet_with_fragment(tx_queue, skb, &state);
if (unlikely(rc)) {
rc2 = NETDEV_TX_BUSY;
goto unwind;
}
/* Move onto the next fragment? */
if (state.in_len == 0) {
if (++frag_i >= skb_shinfo(skb)->nr_frags)
/* End of payload reached. */
break;
rc = tso_get_fragment(&state, efx,
skb_shinfo(skb)->frags + frag_i);
if (rc)
goto mem_err;
}
/* Start at new packet? */
if (state.packet_space == 0 &&
tso_start_new_packet(tx_queue, skb, &state) < 0)
goto mem_err;
}
/* Pass off to hardware */
efx_nic_push_buffers(tx_queue);
tx_queue->tso_bursts++;
return NETDEV_TX_OK;
mem_err:
netif_err(efx, tx_err, efx->net_dev,
"Out of memory for TSO headers, or PCI mapping error\n");
dev_kfree_skb_any(skb);
unwind:
/* Free the DMA mapping we were in the process of writing out */
if (state.unmap_len) {
if (state.unmap_single)
pci_unmap_single(efx->pci_dev, state.unmap_addr,
state.unmap_len, PCI_DMA_TODEVICE);
else
pci_unmap_page(efx->pci_dev, state.unmap_addr,
state.unmap_len, PCI_DMA_TODEVICE);
}
efx_enqueue_unwind(tx_queue);
return rc2;
}
