[netdrvr] sfc: Add TSO support
The SFC4000 controller does not have hardware support for TSO, and the
core GSO code incurs a high cost in allocating and freeing skbs. This
TSO implementation uses lightweight packet header structures and is
substantially faster.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/sfc/tx.c b/drivers/net/sfc/tx.c
index fbb866b..9b436f5 100644
--- a/drivers/net/sfc/tx.c
+++ b/drivers/net/sfc/tx.c
@@ -82,6 +82,46 @@
}
}
+/**
+ * struct efx_tso_header - a DMA mapped buffer for packet headers
+ * @next: Linked list of free ones.
+ * The list is protected by the TX queue lock.
+ * @dma_unmap_len: Length to unmap for an oversize buffer, or 0.
+ * @dma_addr: The DMA address of the header below.
+ *
+ * This controls the memory used for a TSO header. Use TSOH_DATA()
+ * to find the packet header data. Use TSOH_SIZE() to calculate the
+ * total size required for a given packet header length. TSO headers
+ * in the free list are exactly %TSOH_STD_SIZE bytes in size.
+ */
+struct efx_tso_header {
+ union {
+ struct efx_tso_header *next;
+ size_t unmap_len;
+ };
+ dma_addr_t dma_addr;
+};
+
+static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
+ const struct sk_buff *skb);
+static void efx_fini_tso(struct efx_tx_queue *tx_queue);
+static void efx_tsoh_heap_free(struct efx_tx_queue *tx_queue,
+ struct efx_tso_header *tsoh);
+
+static inline void efx_tsoh_free(struct efx_tx_queue *tx_queue,
+ struct efx_tx_buffer *buffer)
+{
+ if (buffer->tsoh) {
+ if (likely(!buffer->tsoh->unmap_len)) {
+ buffer->tsoh->next = tx_queue->tso_headers_free;
+ tx_queue->tso_headers_free = buffer->tsoh;
+ } else {
+ efx_tsoh_heap_free(tx_queue, buffer->tsoh);
+ }
+ buffer->tsoh = NULL;
+ }
+}
+
/*
* Add a socket buffer to a TX queue
@@ -114,6 +154,9 @@
EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
+ if (skb_shinfo((struct sk_buff *)skb)->gso_size)
+ return efx_enqueue_skb_tso(tx_queue, skb);
+
/* Get size of the initial fragment */
len = skb_headlen(skb);
@@ -166,6 +209,8 @@
insert_ptr = (tx_queue->insert_count &
efx->type->txd_ring_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 != 1);
@@ -432,6 +477,9 @@
efx_release_tx_buffers(tx_queue);
+ /* Free up TSO header cache */
+ efx_fini_tso(tx_queue);
+
/* Release queue's stop on port, if any */
if (tx_queue->stopped) {
tx_queue->stopped = 0;
@@ -450,3 +498,619 @@
}
+/* Efx TCP segmentation acceleration.
+ *
+ * Why? Because by doing it here in the driver we can go significantly
+ * faster than the GSO.
+ *
+ * Requires TX checksum offload support.
+ */
+
+/* Number of bytes inserted at the start of a TSO header buffer,
+ * similar to NET_IP_ALIGN.
+ */
+#if defined(__i386__) || defined(__x86_64__)
+#define TSOH_OFFSET 0
+#else
+#define TSOH_OFFSET NET_IP_ALIGN
+#endif
+
+#define TSOH_BUFFER(tsoh) ((u8 *)(tsoh + 1) + TSOH_OFFSET)
+
+/* Total size of struct efx_tso_header, buffer and padding */
+#define TSOH_SIZE(hdr_len) \
+ (sizeof(struct efx_tso_header) + TSOH_OFFSET + hdr_len)
+
+/* Size of blocks on free list. Larger blocks must be allocated from
+ * the heap.
+ */
+#define TSOH_STD_SIZE 128
+
+#define PTR_DIFF(p1, p2) ((u8 *)(p1) - (u8 *)(p2))
+#define ETH_HDR_LEN(skb) (skb_network_header(skb) - (skb)->data)
+#define SKB_TCP_OFF(skb) PTR_DIFF(tcp_hdr(skb), (skb)->data)
+#define SKB_IPV4_OFF(skb) PTR_DIFF(ip_hdr(skb), (skb)->data)
+
+/**
+ * struct tso_state - TSO state for an SKB
+ * @remaining_len: Bytes of data we've yet to segment
+ * @seqnum: Current sequence number
+ * @packet_space: Remaining space in current packet
+ * @ifc: Input fragment cursor.
+ * Where we are in the current fragment of the incoming SKB. These
+ * values get updated in place when we split a fragment over
+ * multiple packets.
+ * @p: Parameters.
+ * These values are set once at the start of the TSO send and do
+ * not get changed as the routine progresses.
+ *
+ * The state used during segmentation. It is put into this data structure
+ * just to make it easy to pass into inline functions.
+ */
+struct tso_state {
+ unsigned remaining_len;
+ unsigned seqnum;
+ unsigned packet_space;
+
+ struct {
+ /* DMA address of current position */
+ dma_addr_t dma_addr;
+ /* Remaining length */
+ unsigned int len;
+ /* DMA address and length of the whole fragment */
+ unsigned int unmap_len;
+ dma_addr_t unmap_addr;
+ struct page *page;
+ unsigned page_off;
+ } ifc;
+
+ struct {
+ /* The number of bytes of header */
+ unsigned int header_length;
+
+ /* The number of bytes to put in each outgoing segment. */
+ int full_packet_size;
+
+ /* Current IPv4 ID, host endian. */
+ unsigned ipv4_id;
+ } p;
+};
+
+
+/*
+ * Verify that our various assumptions about sk_buffs and the conditions
+ * under which TSO will be attempted hold true.
+ */
+static inline void efx_tso_check_safe(const struct sk_buff *skb)
+{
+ EFX_BUG_ON_PARANOID(skb->protocol != htons(ETH_P_IP));
+ EFX_BUG_ON_PARANOID(((struct ethhdr *)skb->data)->h_proto !=
+ skb->protocol);
+ EFX_BUG_ON_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP);
+ EFX_BUG_ON_PARANOID((PTR_DIFF(tcp_hdr(skb), skb->data)
+ + (tcp_hdr(skb)->doff << 2u)) >
+ skb_headlen(skb));
+}
+
+
+/*
+ * Allocate a page worth of efx_tso_header structures, and string them
+ * into the tx_queue->tso_headers_free linked list. Return 0 or -ENOMEM.
+ */
+static int efx_tsoh_block_alloc(struct efx_tx_queue *tx_queue)
+{
+
+ struct pci_dev *pci_dev = tx_queue->efx->pci_dev;
+ struct efx_tso_header *tsoh;
+ dma_addr_t dma_addr;
+ u8 *base_kva, *kva;
+
+ base_kva = pci_alloc_consistent(pci_dev, PAGE_SIZE, &dma_addr);
+ if (base_kva == NULL) {
+ EFX_ERR(tx_queue->efx, "Unable to allocate page for TSO"
+ " headers\n");
+ return -ENOMEM;
+ }
+
+ /* pci_alloc_consistent() allocates pages. */
+ EFX_BUG_ON_PARANOID(dma_addr & (PAGE_SIZE - 1u));
+
+ for (kva = base_kva; kva < base_kva + PAGE_SIZE; kva += TSOH_STD_SIZE) {
+ tsoh = (struct efx_tso_header *)kva;
+ tsoh->dma_addr = dma_addr + (TSOH_BUFFER(tsoh) - base_kva);
+ tsoh->next = tx_queue->tso_headers_free;
+ tx_queue->tso_headers_free = tsoh;
+ }
+
+ return 0;
+}
+
+
+/* Free up a TSO header, and all others in the same page. */
+static void efx_tsoh_block_free(struct efx_tx_queue *tx_queue,
+ struct efx_tso_header *tsoh,
+ struct pci_dev *pci_dev)
+{
+ struct efx_tso_header **p;
+ unsigned long base_kva;
+ dma_addr_t base_dma;
+
+ base_kva = (unsigned long)tsoh & PAGE_MASK;
+ base_dma = tsoh->dma_addr & PAGE_MASK;
+
+ p = &tx_queue->tso_headers_free;
+ while (*p != NULL)
+ if (((unsigned long)*p & PAGE_MASK) == base_kva)
+ *p = (*p)->next;
+ else
+ p = &(*p)->next;
+
+ pci_free_consistent(pci_dev, PAGE_SIZE, (void *)base_kva, base_dma);
+}
+
+static struct efx_tso_header *
+efx_tsoh_heap_alloc(struct efx_tx_queue *tx_queue, size_t header_len)
+{
+ struct efx_tso_header *tsoh;
+
+ tsoh = kmalloc(TSOH_SIZE(header_len), GFP_ATOMIC | GFP_DMA);
+ if (unlikely(!tsoh))
+ return NULL;
+
+ tsoh->dma_addr = pci_map_single(tx_queue->efx->pci_dev,
+ TSOH_BUFFER(tsoh), header_len,
+ PCI_DMA_TODEVICE);
+ if (unlikely(pci_dma_mapping_error(tsoh->dma_addr))) {
+ kfree(tsoh);
+ return NULL;
+ }
+
+ tsoh->unmap_len = header_len;
+ return tsoh;
+}
+
+static void
+efx_tsoh_heap_free(struct efx_tx_queue *tx_queue, struct efx_tso_header *tsoh)
+{
+ pci_unmap_single(tx_queue->efx->pci_dev,
+ tsoh->dma_addr, tsoh->unmap_len,
+ PCI_DMA_TODEVICE);
+ kfree(tsoh);
+}
+
+/**
+ * efx_tx_queue_insert - push descriptors onto the TX queue
+ * @tx_queue: Efx TX queue
+ * @dma_addr: DMA address of fragment
+ * @len: Length of fragment
+ * @skb: Only non-null for end of last segment
+ * @end_of_packet: True if last fragment in a packet
+ * @unmap_addr: DMA address of fragment for unmapping
+ * @unmap_len: Only set this in last segment of a fragment
+ *
+ * Push descriptors onto the TX queue. Return 0 on success or 1 if
+ * @tx_queue full.
+ */
+static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue,
+ dma_addr_t dma_addr, unsigned len,
+ const struct sk_buff *skb, int end_of_packet,
+ dma_addr_t unmap_addr, unsigned unmap_len)
+{
+ struct efx_tx_buffer *buffer;
+ struct efx_nic *efx = tx_queue->efx;
+ unsigned dma_len, fill_level, insert_ptr, misalign;
+ int q_space;
+
+ EFX_BUG_ON_PARANOID(len <= 0);
+
+ fill_level = tx_queue->insert_count - tx_queue->old_read_count;
+ /* -1 as there is no way to represent all descriptors used */
+ q_space = efx->type->txd_ring_mask - 1 - fill_level;
+
+ while (1) {
+ 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.
+ */
+ ++tx_queue->stopped;
+ /* This memory barrier protects the change of
+ * stopped from the access of read_count. */
+ smp_mb();
+ tx_queue->old_read_count =
+ *(volatile unsigned *)&tx_queue->read_count;
+ fill_level = (tx_queue->insert_count
+ - tx_queue->old_read_count);
+ q_space = efx->type->txd_ring_mask - 1 - fill_level;
+ if (unlikely(q_space-- <= 0))
+ return 1;
+ smp_mb();
+ --tx_queue->stopped;
+ }
+
+ insert_ptr = tx_queue->insert_count & efx->type->txd_ring_mask;
+ buffer = &tx_queue->buffer[insert_ptr];
+ ++tx_queue->insert_count;
+
+ EFX_BUG_ON_PARANOID(tx_queue->insert_count -
+ tx_queue->read_count >
+ efx->type->txd_ring_mask);
+
+ efx_tsoh_free(tx_queue, buffer);
+ EFX_BUG_ON_PARANOID(buffer->len);
+ EFX_BUG_ON_PARANOID(buffer->unmap_len);
+ EFX_BUG_ON_PARANOID(buffer->skb);
+ EFX_BUG_ON_PARANOID(buffer->continuation != 1);
+ EFX_BUG_ON_PARANOID(buffer->tsoh);
+
+ buffer->dma_addr = dma_addr;
+
+ /* Ensure we do not cross a boundary unsupported by H/W */
+ dma_len = (~dma_addr & efx->type->tx_dma_mask) + 1;
+
+ misalign = (unsigned)dma_addr & efx->type->bug5391_mask;
+ if (misalign && dma_len + misalign > 512)
+ dma_len = 512 - misalign;
+
+ /* If there is enough space to send then do so */
+ if (dma_len >= len)
+ break;
+
+ buffer->len = dma_len; /* Don't set the other members */
+ dma_addr += dma_len;
+ len -= dma_len;
+ }
+
+ EFX_BUG_ON_PARANOID(!len);
+ buffer->len = len;
+ buffer->skb = skb;
+ buffer->continuation = !end_of_packet;
+ buffer->unmap_addr = unmap_addr;
+ buffer->unmap_len = unmap_len;
+ return 0;
+}
+
+
+/*
+ * Put a TSO header into the TX queue.
+ *
+ * This is special-cased because we know that it is small enough to fit in
+ * a single fragment, and we know it doesn't cross a page boundary. It
+ * also allows us to not worry about end-of-packet etc.
+ */
+static inline void efx_tso_put_header(struct efx_tx_queue *tx_queue,
+ struct efx_tso_header *tsoh, unsigned len)
+{
+ struct efx_tx_buffer *buffer;
+
+ buffer = &tx_queue->buffer[tx_queue->insert_count &
+ tx_queue->efx->type->txd_ring_mask];
+ efx_tsoh_free(tx_queue, buffer);
+ EFX_BUG_ON_PARANOID(buffer->len);
+ EFX_BUG_ON_PARANOID(buffer->unmap_len);
+ EFX_BUG_ON_PARANOID(buffer->skb);
+ EFX_BUG_ON_PARANOID(buffer->continuation != 1);
+ EFX_BUG_ON_PARANOID(buffer->tsoh);
+ buffer->len = len;
+ buffer->dma_addr = tsoh->dma_addr;
+ buffer->tsoh = tsoh;
+
+ ++tx_queue->insert_count;
+}
+
+
+/* Remove descriptors put into a tx_queue. */
+static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
+{
+ struct efx_tx_buffer *buffer;
+
+ /* Work backwards until we hit the original insert pointer value */
+ while (tx_queue->insert_count != tx_queue->write_count) {
+ --tx_queue->insert_count;
+ buffer = &tx_queue->buffer[tx_queue->insert_count &
+ tx_queue->efx->type->txd_ring_mask];
+ efx_tsoh_free(tx_queue, buffer);
+ EFX_BUG_ON_PARANOID(buffer->skb);
+ buffer->len = 0;
+ buffer->continuation = 1;
+ if (buffer->unmap_len) {
+ pci_unmap_page(tx_queue->efx->pci_dev,
+ buffer->unmap_addr,
+ buffer->unmap_len, PCI_DMA_TODEVICE);
+ buffer->unmap_len = 0;
+ }
+ }
+}
+
+
+/* Parse the SKB header and initialise state. */
+static inline void tso_start(struct tso_state *st, const struct sk_buff *skb)
+{
+ /* All ethernet/IP/TCP headers combined size is TCP header size
+ * plus offset of TCP header relative to start of packet.
+ */
+ st->p.header_length = ((tcp_hdr(skb)->doff << 2u)
+ + PTR_DIFF(tcp_hdr(skb), skb->data));
+ st->p.full_packet_size = (st->p.header_length
+ + skb_shinfo(skb)->gso_size);
+
+ st->p.ipv4_id = ntohs(ip_hdr(skb)->id);
+ st->seqnum = ntohl(tcp_hdr(skb)->seq);
+
+ EFX_BUG_ON_PARANOID(tcp_hdr(skb)->urg);
+ EFX_BUG_ON_PARANOID(tcp_hdr(skb)->syn);
+ EFX_BUG_ON_PARANOID(tcp_hdr(skb)->rst);
+
+ st->packet_space = st->p.full_packet_size;
+ st->remaining_len = skb->len - st->p.header_length;
+}
+
+
+/**
+ * tso_get_fragment - record fragment details and map for DMA
+ * @st: TSO state
+ * @efx: Efx NIC
+ * @data: Pointer to fragment data
+ * @len: Length of fragment
+ *
+ * Record fragment details and map for DMA. Return 0 on success, or
+ * -%ENOMEM if DMA mapping fails.
+ */
+static inline int tso_get_fragment(struct tso_state *st, struct efx_nic *efx,
+ int len, struct page *page, int page_off)
+{
+
+ st->ifc.unmap_addr = pci_map_page(efx->pci_dev, page, page_off,
+ len, PCI_DMA_TODEVICE);
+ if (likely(!pci_dma_mapping_error(st->ifc.unmap_addr))) {
+ st->ifc.unmap_len = len;
+ st->ifc.len = len;
+ st->ifc.dma_addr = st->ifc.unmap_addr;
+ st->ifc.page = page;
+ st->ifc.page_off = page_off;
+ return 0;
+ }
+ return -ENOMEM;
+}
+
+
+/**
+ * tso_fill_packet_with_fragment - form descriptors for the current fragment
+ * @tx_queue: Efx TX queue
+ * @skb: Socket buffer
+ * @st: TSO state
+ *
+ * Form descriptors for the current fragment, until we reach the end
+ * of fragment or end-of-packet. Return 0 on success, 1 if not enough
+ * space in @tx_queue.
+ */
+static inline int tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue,
+ const struct sk_buff *skb,
+ struct tso_state *st)
+{
+
+ int n, end_of_packet, rc;
+
+ if (st->ifc.len == 0)
+ return 0;
+ if (st->packet_space == 0)
+ return 0;
+
+ EFX_BUG_ON_PARANOID(st->ifc.len <= 0);
+ EFX_BUG_ON_PARANOID(st->packet_space <= 0);
+
+ n = min(st->ifc.len, st->packet_space);
+
+ st->packet_space -= n;
+ st->remaining_len -= n;
+ st->ifc.len -= n;
+ st->ifc.page_off += n;
+ end_of_packet = st->remaining_len == 0 || st->packet_space == 0;
+
+ rc = efx_tx_queue_insert(tx_queue, st->ifc.dma_addr, n,
+ st->remaining_len ? NULL : skb,
+ end_of_packet, st->ifc.unmap_addr,
+ st->ifc.len ? 0 : st->ifc.unmap_len);
+
+ st->ifc.dma_addr += n;
+
+ return rc;
+}
+
+
+/**
+ * tso_start_new_packet - generate a new header and prepare for the new packet
+ * @tx_queue: Efx TX queue
+ * @skb: Socket buffer
+ * @st: TSO state
+ *
+ * Generate a new header and prepare for the new packet. Return 0 on
+ * success, or -1 if failed to alloc header.
+ */
+static inline int tso_start_new_packet(struct efx_tx_queue *tx_queue,
+ const struct sk_buff *skb,
+ struct tso_state *st)
+{
+ struct efx_tso_header *tsoh;
+ struct iphdr *tsoh_iph;
+ struct tcphdr *tsoh_th;
+ unsigned ip_length;
+ u8 *header;
+
+ /* Allocate a DMA-mapped header buffer. */
+ if (likely(TSOH_SIZE(st->p.header_length) <= TSOH_STD_SIZE)) {
+ if (tx_queue->tso_headers_free == NULL)
+ if (efx_tsoh_block_alloc(tx_queue))
+ return -1;
+ EFX_BUG_ON_PARANOID(!tx_queue->tso_headers_free);
+ tsoh = tx_queue->tso_headers_free;
+ tx_queue->tso_headers_free = tsoh->next;
+ tsoh->unmap_len = 0;
+ } else {
+ tx_queue->tso_long_headers++;
+ tsoh = efx_tsoh_heap_alloc(tx_queue, st->p.header_length);
+ if (unlikely(!tsoh))
+ return -1;
+ }
+
+ header = TSOH_BUFFER(tsoh);
+ tsoh_th = (struct tcphdr *)(header + SKB_TCP_OFF(skb));
+ tsoh_iph = (struct iphdr *)(header + SKB_IPV4_OFF(skb));
+
+ /* Copy and update the headers. */
+ memcpy(header, skb->data, st->p.header_length);
+
+ tsoh_th->seq = htonl(st->seqnum);
+ st->seqnum += skb_shinfo(skb)->gso_size;
+ if (st->remaining_len > skb_shinfo(skb)->gso_size) {
+ /* This packet will not finish the TSO burst. */
+ ip_length = st->p.full_packet_size - ETH_HDR_LEN(skb);
+ tsoh_th->fin = 0;
+ tsoh_th->psh = 0;
+ } else {
+ /* This packet will be the last in the TSO burst. */
+ ip_length = (st->p.header_length - ETH_HDR_LEN(skb)
+ + st->remaining_len);
+ tsoh_th->fin = tcp_hdr(skb)->fin;
+ tsoh_th->psh = tcp_hdr(skb)->psh;
+ }
+ tsoh_iph->tot_len = htons(ip_length);
+
+ /* Linux leaves suitable gaps in the IP ID space for us to fill. */
+ tsoh_iph->id = htons(st->p.ipv4_id);
+ st->p.ipv4_id++;
+
+ st->packet_space = skb_shinfo(skb)->gso_size;
+ ++tx_queue->tso_packets;
+
+ /* Form a descriptor for this header. */
+ efx_tso_put_header(tx_queue, tsoh, st->p.header_length);
+
+ return 0;
+}
+
+
+/**
+ * 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,
+ const struct sk_buff *skb)
+{
+ int frag_i, rc, rc2 = NETDEV_TX_OK;
+ struct tso_state state;
+ skb_frag_t *f;
+
+ /* Verify TSO is safe - these checks should never fail. */
+ efx_tso_check_safe(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.p.header_length) {
+ /* Grab the first payload fragment. */
+ EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1);
+ frag_i = 0;
+ f = &skb_shinfo(skb)->frags[frag_i];
+ rc = tso_get_fragment(&state, tx_queue->efx,
+ f->size, f->page, f->page_offset);
+ if (rc)
+ goto mem_err;
+ } else {
+ /* It may look like this code fragment assumes that the
+ * skb->data portion does not cross a page boundary, but
+ * that is not the case. It is guaranteed to be direct
+ * mapped memory, and therefore is physically contiguous,
+ * and so DMA will work fine. kmap_atomic() on this region
+ * will just return the direct mapping, so that will work
+ * too.
+ */
+ int page_off = (unsigned long)skb->data & (PAGE_SIZE - 1);
+ int hl = state.p.header_length;
+ rc = tso_get_fragment(&state, tx_queue->efx,
+ skb_headlen(skb) - hl,
+ virt_to_page(skb->data), page_off + hl);
+ 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))
+ goto stop;
+
+ /* Move onto the next fragment? */
+ if (state.ifc.len == 0) {
+ if (++frag_i >= skb_shinfo(skb)->nr_frags)
+ /* End of payload reached. */
+ break;
+ f = &skb_shinfo(skb)->frags[frag_i];
+ rc = tso_get_fragment(&state, tx_queue->efx,
+ f->size, f->page, f->page_offset);
+ 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 */
+ falcon_push_buffers(tx_queue);
+
+ tx_queue->tso_bursts++;
+ return NETDEV_TX_OK;
+
+ mem_err:
+ EFX_ERR(tx_queue->efx, "Out of memory for TSO headers, or PCI mapping"
+ " error\n");
+ dev_kfree_skb_any((struct sk_buff *)skb);
+ goto unwind;
+
+ stop:
+ rc2 = NETDEV_TX_BUSY;
+
+ /* Stop the queue if it wasn't stopped before. */
+ if (tx_queue->stopped == 1)
+ efx_stop_queue(tx_queue->efx);
+
+ unwind:
+ efx_enqueue_unwind(tx_queue);
+ return rc2;
+}
+
+
+/*
+ * Free up all TSO datastructures associated with tx_queue. This
+ * routine should be called only once the tx_queue is both empty and
+ * will no longer be used.
+ */
+static void efx_fini_tso(struct efx_tx_queue *tx_queue)
+{
+ unsigned i;
+
+ if (tx_queue->buffer)
+ for (i = 0; i <= tx_queue->efx->type->txd_ring_mask; ++i)
+ efx_tsoh_free(tx_queue, &tx_queue->buffer[i]);
+
+ while (tx_queue->tso_headers_free != NULL)
+ efx_tsoh_block_free(tx_queue, tx_queue->tso_headers_free,
+ tx_queue->efx->pci_dev);
+}