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sfc: Cleaned up struct tso_state fields
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Squashed nested structures.

Renamed remaining_len to out_len, ifc.len to in_len, header_length to
header_len.

Moved ipv4_id into the group of output variables where it belongs.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
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Ben Hutchings authored and Jeff Garzik committed Sep 3, 2008
1 parent 2850656 commit 23d9e60
Showing 1 changed file with 75 additions and 86 deletions.
161 changes: 75 additions & 86 deletions drivers/net/sfc/tx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -540,46 +540,37 @@ void efx_remove_tx_queue(struct efx_tx_queue *tx_queue)

/**
* struct tso_state - TSO state for an SKB
* @remaining_len: Bytes of data we've yet to segment
* @out_len: Remaining length in current segment
* @seqnum: Current sequence number
* @ipv4_id: Current IPv4 ID, host endian
* @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.
* @dma_addr: DMA address of current position
* @in_len: Remaining length in current SKB fragment
* @unmap_len: Length of SKB fragment
* @unmap_addr: DMA address of SKB fragment
* @unmap_single: DMA single vs page mapping flag
* @header_len: Number of bytes of header
* @full_packet_size: Number of bytes to put in each outgoing segment
*
* 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;
/* Output position */
unsigned out_len;
unsigned seqnum;
unsigned ipv4_id;
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;
bool unmap_single;
} 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;
/* Input position */
dma_addr_t dma_addr;
unsigned in_len;
unsigned unmap_len;
dma_addr_t unmap_addr;
bool unmap_single;

unsigned header_len;
int full_packet_size;
};


Expand Down Expand Up @@ -840,35 +831,34 @@ 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->header_len = ((tcp_hdr(skb)->doff << 2u)
+ PTR_DIFF(tcp_hdr(skb), skb->data));
st->full_packet_size = st->header_len + skb_shinfo(skb)->gso_size;

st->p.ipv4_id = ntohs(ip_hdr(skb)->id);
st->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;
st->ifc.unmap_len = 0;
st->ifc.unmap_single = false;
st->packet_space = st->full_packet_size;
st->out_len = skb->len - st->header_len;
st->unmap_len = 0;
st->unmap_single = false;
}

static inline int tso_get_fragment(struct tso_state *st, struct efx_nic *efx,
skb_frag_t *frag)
{
st->ifc.unmap_addr = pci_map_page(efx->pci_dev, frag->page,
frag->page_offset, frag->size,
PCI_DMA_TODEVICE);
if (likely(!pci_dma_mapping_error(efx->pci_dev, st->ifc.unmap_addr))) {
st->ifc.unmap_single = false;
st->ifc.unmap_len = frag->size;
st->ifc.len = frag->size;
st->ifc.dma_addr = st->ifc.unmap_addr;
st->unmap_addr = pci_map_page(efx->pci_dev, frag->page,
frag->page_offset, frag->size,
PCI_DMA_TODEVICE);
if (likely(!pci_dma_mapping_error(efx->pci_dev, st->unmap_addr))) {
st->unmap_single = false;
st->unmap_len = frag->size;
st->in_len = frag->size;
st->dma_addr = st->unmap_addr;
return 0;
}
return -ENOMEM;
Expand All @@ -878,16 +868,16 @@ static inline int
tso_get_head_fragment(struct tso_state *st, struct efx_nic *efx,
const struct sk_buff *skb)
{
int hl = st->p.header_length;
int hl = st->header_len;
int len = skb_headlen(skb) - hl;

st->ifc.unmap_addr = pci_map_single(efx->pci_dev, skb->data + hl,
len, PCI_DMA_TODEVICE);
if (likely(!pci_dma_mapping_error(efx->pci_dev, st->ifc.unmap_addr))) {
st->ifc.unmap_single = true;
st->ifc.unmap_len = len;
st->ifc.len = len;
st->ifc.dma_addr = st->ifc.unmap_addr;
st->unmap_addr = pci_map_single(efx->pci_dev, skb->data + hl,
len, PCI_DMA_TODEVICE);
if (likely(!pci_dma_mapping_error(efx->pci_dev, st->unmap_addr))) {
st->unmap_single = true;
st->unmap_len = len;
st->in_len = len;
st->dma_addr = st->unmap_addr;
return 0;
}
return -ENOMEM;
Expand All @@ -911,38 +901,38 @@ static inline int tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue,
struct efx_tx_buffer *buffer;
int n, end_of_packet, rc;

if (st->ifc.len == 0)
if (st->in_len == 0)
return 0;
if (st->packet_space == 0)
return 0;

EFX_BUG_ON_PARANOID(st->ifc.len <= 0);
EFX_BUG_ON_PARANOID(st->in_len <= 0);
EFX_BUG_ON_PARANOID(st->packet_space <= 0);

n = min(st->ifc.len, st->packet_space);
n = min(st->in_len, st->packet_space);

st->packet_space -= n;
st->remaining_len -= n;
st->ifc.len -= n;
st->out_len -= n;
st->in_len -= n;

rc = efx_tx_queue_insert(tx_queue, st->ifc.dma_addr, n, &buffer);
rc = efx_tx_queue_insert(tx_queue, st->dma_addr, n, &buffer);
if (likely(rc == 0)) {
if (st->remaining_len == 0)
if (st->out_len == 0)
/* Transfer ownership of the skb */
buffer->skb = skb;

end_of_packet = st->remaining_len == 0 || st->packet_space == 0;
end_of_packet = st->out_len == 0 || st->packet_space == 0;
buffer->continuation = !end_of_packet;

if (st->ifc.len == 0) {
if (st->in_len == 0) {
/* Transfer ownership of the pci mapping */
buffer->unmap_len = st->ifc.unmap_len;
buffer->unmap_single = st->ifc.unmap_single;
st->ifc.unmap_len = 0;
buffer->unmap_len = st->unmap_len;
buffer->unmap_single = st->unmap_single;
st->unmap_len = 0;
}
}

st->ifc.dma_addr += n;
st->dma_addr += n;
return rc;
}

Expand All @@ -967,7 +957,7 @@ static inline int tso_start_new_packet(struct efx_tx_queue *tx_queue,
u8 *header;

/* Allocate a DMA-mapped header buffer. */
if (likely(TSOH_SIZE(st->p.header_length) <= TSOH_STD_SIZE)) {
if (likely(TSOH_SIZE(st->header_len) <= TSOH_STD_SIZE)) {
if (tx_queue->tso_headers_free == NULL) {
if (efx_tsoh_block_alloc(tx_queue))
return -1;
Expand All @@ -978,7 +968,7 @@ static inline int tso_start_new_packet(struct efx_tx_queue *tx_queue,
tsoh->unmap_len = 0;
} else {
tx_queue->tso_long_headers++;
tsoh = efx_tsoh_heap_alloc(tx_queue, st->p.header_length);
tsoh = efx_tsoh_heap_alloc(tx_queue, st->header_len);
if (unlikely(!tsoh))
return -1;
}
Expand All @@ -988,33 +978,32 @@ static inline int tso_start_new_packet(struct efx_tx_queue *tx_queue,
tsoh_iph = (struct iphdr *)(header + SKB_IPV4_OFF(skb));

/* Copy and update the headers. */
memcpy(header, skb->data, st->p.header_length);
memcpy(header, skb->data, st->header_len);

tsoh_th->seq = htonl(st->seqnum);
st->seqnum += skb_shinfo(skb)->gso_size;
if (st->remaining_len > skb_shinfo(skb)->gso_size) {
if (st->out_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);
ip_length = st->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);
ip_length = st->header_len - ETH_HDR_LEN(skb) + st->out_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++;
tsoh_iph->id = htons(st->ipv4_id);
st->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);
efx_tso_put_header(tx_queue, tsoh, st->header_len);

return 0;
}
Expand Down Expand Up @@ -1048,7 +1037,7 @@ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
/* 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) {
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;
Expand All @@ -1072,7 +1061,7 @@ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
goto stop;

/* Move onto the next fragment? */
if (state.ifc.len == 0) {
if (state.in_len == 0) {
if (++frag_i >= skb_shinfo(skb)->nr_frags)
/* End of payload reached. */
break;
Expand Down Expand Up @@ -1108,13 +1097,13 @@ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,

unwind:
/* Free the DMA mapping we were in the process of writing out */
if (state.ifc.unmap_len) {
if (state.ifc.unmap_single)
pci_unmap_single(efx->pci_dev, state.ifc.unmap_addr,
state.ifc.unmap_len, PCI_DMA_TODEVICE);
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.ifc.unmap_addr,
state.ifc.unmap_len, PCI_DMA_TODEVICE);
pci_unmap_page(efx->pci_dev, state.unmap_addr,
state.unmap_len, PCI_DMA_TODEVICE);
}

efx_enqueue_unwind(tx_queue);
Expand Down

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