From 7668ff9c2ad7d354655e23afa836a92d54d2ea63 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 17 May 2012 20:52:20 +0100 Subject: [PATCH] sfc: Refactor struct efx_tx_buffer to use a flags field Add a flags field to struct efx_tx_buffer, replacing the continuation and map_single booleans. Since a single descriptor cannot be both a TSO header and the last descriptor for an skb, unionise efx_tx_buffer::{skb,tsoh} and add flags for validity of these fields. Clear all flags in free buffers (whereas previously the continuation flag would be set). Signed-off-by: Ben Hutchings --- drivers/net/ethernet/sfc/net_driver.h | 27 +++++----- drivers/net/ethernet/sfc/nic.c | 4 +- drivers/net/ethernet/sfc/tx.c | 78 +++++++++++++-------------- 3 files changed, 53 insertions(+), 56 deletions(-) diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h index cd9c0a989692..0ac01fa6e63c 100644 --- a/drivers/net/ethernet/sfc/net_driver.h +++ b/drivers/net/ethernet/sfc/net_driver.h @@ -91,29 +91,30 @@ struct efx_special_buffer { }; /** - * struct efx_tx_buffer - An Efx TX buffer - * @skb: The associated socket buffer. - * Set only on the final fragment of a packet; %NULL for all other - * fragments. When this fragment completes, then we can free this - * skb. - * @tsoh: The associated TSO header structure, or %NULL if this - * buffer is not a TSO header. + * struct efx_tx_buffer - buffer state for a TX descriptor + * @skb: When @flags & %EFX_TX_BUF_SKB, the associated socket buffer to be + * freed when descriptor completes + * @tsoh: When @flags & %EFX_TX_BUF_TSOH, the associated TSO header structure. * @dma_addr: DMA address of the fragment. + * @flags: Flags for allocation and DMA mapping type * @len: Length of this fragment. * This field is zero when the queue slot is empty. - * @continuation: True if this fragment is not the end of a packet. - * @unmap_single: True if dma_unmap_single should be used. * @unmap_len: Length of this fragment to unmap */ struct efx_tx_buffer { - const struct sk_buff *skb; - struct efx_tso_header *tsoh; + union { + const struct sk_buff *skb; + struct efx_tso_header *tsoh; + }; dma_addr_t dma_addr; + unsigned short flags; unsigned short len; - bool continuation; - bool unmap_single; unsigned short unmap_len; }; +#define EFX_TX_BUF_CONT 1 /* not last descriptor of packet */ +#define EFX_TX_BUF_SKB 2 /* buffer is last part of skb */ +#define EFX_TX_BUF_TSOH 4 /* buffer is TSO header */ +#define EFX_TX_BUF_MAP_SINGLE 8 /* buffer was mapped with dma_map_single() */ /** * struct efx_tx_queue - An Efx TX queue diff --git a/drivers/net/ethernet/sfc/nic.c b/drivers/net/ethernet/sfc/nic.c index 326d799762d6..aa113709831d 100644 --- a/drivers/net/ethernet/sfc/nic.c +++ b/drivers/net/ethernet/sfc/nic.c @@ -401,8 +401,10 @@ void efx_nic_push_buffers(struct efx_tx_queue *tx_queue) ++tx_queue->write_count; /* Create TX descriptor ring entry */ + BUILD_BUG_ON(EFX_TX_BUF_CONT != 1); EFX_POPULATE_QWORD_4(*txd, - FSF_AZ_TX_KER_CONT, buffer->continuation, + FSF_AZ_TX_KER_CONT, + buffer->flags & EFX_TX_BUF_CONT, FSF_AZ_TX_KER_BYTE_COUNT, buffer->len, FSF_AZ_TX_KER_BUF_REGION, 0, FSF_AZ_TX_KER_BUF_ADDR, buffer->dma_addr); diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c index 18713436b443..24c82f3ce0f3 100644 --- a/drivers/net/ethernet/sfc/tx.c +++ b/drivers/net/ethernet/sfc/tx.c @@ -39,25 +39,25 @@ static void efx_dequeue_buffer(struct efx_tx_queue *tx_queue, struct device *dma_dev = &tx_queue->efx->pci_dev->dev; dma_addr_t unmap_addr = (buffer->dma_addr + buffer->len - buffer->unmap_len); - if (buffer->unmap_single) + if (buffer->flags & EFX_TX_BUF_MAP_SINGLE) dma_unmap_single(dma_dev, unmap_addr, buffer->unmap_len, DMA_TO_DEVICE); else dma_unmap_page(dma_dev, unmap_addr, buffer->unmap_len, DMA_TO_DEVICE); buffer->unmap_len = 0; - buffer->unmap_single = false; } - if (buffer->skb) { + if (buffer->flags & EFX_TX_BUF_SKB) { (*pkts_compl)++; (*bytes_compl) += buffer->skb->len; dev_kfree_skb_any((struct sk_buff *) buffer->skb); - buffer->skb = NULL; netif_vdbg(tx_queue->efx, tx_done, tx_queue->efx->net_dev, "TX queue %d transmission id %x complete\n", tx_queue->queue, tx_queue->read_count); } + + buffer->flags &= EFX_TX_BUF_TSOH; } /** @@ -89,14 +89,14 @@ static void efx_tsoh_heap_free(struct efx_tx_queue *tx_queue, static void efx_tsoh_free(struct efx_tx_queue *tx_queue, struct efx_tx_buffer *buffer) { - if (buffer->tsoh) { + if (buffer->flags & EFX_TX_BUF_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; + buffer->flags &= ~EFX_TX_BUF_TSOH; } } @@ -163,7 +163,7 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) 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; + unsigned short dma_flags; int q_space, i = 0; netdev_tx_t rc = NETDEV_TX_OK; @@ -190,7 +190,7 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) * since this is more efficient on machines with sparse * memory. */ - unmap_single = true; + dma_flags = EFX_TX_BUF_MAP_SINGLE; dma_addr = dma_map_single(dma_dev, skb->data, len, PCI_DMA_TODEVICE); /* Process all fragments */ @@ -234,10 +234,8 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) 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->flags); 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); @@ -247,13 +245,14 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) /* Fill out per descriptor fields */ buffer->len = dma_len; buffer->dma_addr = dma_addr; + buffer->flags = EFX_TX_BUF_CONT; 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->flags = EFX_TX_BUF_CONT | dma_flags; buffer->unmap_len = unmap_len; unmap_len = 0; @@ -264,14 +263,14 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) len = skb_frag_size(fragment); i++; /* Map for DMA */ - unmap_single = false; + dma_flags = 0; dma_addr = skb_frag_dma_map(dma_dev, fragment, 0, len, DMA_TO_DEVICE); } /* Transfer ownership of the skb to the final buffer */ buffer->skb = skb; - buffer->continuation = false; + buffer->flags = EFX_TX_BUF_SKB | dma_flags; netdev_tx_sent_queue(tx_queue->core_txq, skb->len); @@ -302,7 +301,7 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb) /* Free the fragment we were mid-way through pushing */ if (unmap_len) { - if (unmap_single) + if (dma_flags & EFX_TX_BUF_MAP_SINGLE) dma_unmap_single(dma_dev, unmap_addr, unmap_len, DMA_TO_DEVICE); else @@ -340,7 +339,6 @@ static void efx_dequeue_buffers(struct efx_tx_queue *tx_queue, } efx_dequeue_buffer(tx_queue, buffer, pkts_compl, bytes_compl); - buffer->continuation = true; buffer->len = 0; ++tx_queue->read_count; @@ -484,7 +482,7 @@ int efx_probe_tx_queue(struct efx_tx_queue *tx_queue) { struct efx_nic *efx = tx_queue->efx; unsigned int entries; - int i, rc; + int rc; /* Create the smallest power-of-two aligned ring */ entries = max(roundup_pow_of_two(efx->txq_entries), EFX_MIN_DMAQ_SIZE); @@ -500,8 +498,6 @@ int efx_probe_tx_queue(struct efx_tx_queue *tx_queue) GFP_KERNEL); if (!tx_queue->buffer) return -ENOMEM; - for (i = 0; i <= tx_queue->ptr_mask; ++i) - tx_queue->buffer[i].continuation = true; /* Allocate hardware ring */ rc = efx_nic_probe_tx(tx_queue); @@ -546,7 +542,6 @@ void efx_release_tx_buffers(struct efx_tx_queue *tx_queue) unsigned int pkts_compl = 0, bytes_compl = 0; buffer = &tx_queue->buffer[tx_queue->read_count & tx_queue->ptr_mask]; efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl); - buffer->continuation = true; buffer->len = 0; ++tx_queue->read_count; @@ -631,7 +626,7 @@ void efx_remove_tx_queue(struct efx_tx_queue *tx_queue) * @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 + * @dma_flags: TX buffer flags for DMA mapping - %EFX_TX_BUF_MAP_SINGLE or 0 * @protocol: Network protocol (after any VLAN header) * @header_len: Number of bytes of header * @full_packet_size: Number of bytes to put in each outgoing segment @@ -651,7 +646,7 @@ struct tso_state { unsigned in_len; unsigned unmap_len; dma_addr_t unmap_addr; - bool unmap_single; + unsigned short dma_flags; __be16 protocol; unsigned header_len; @@ -833,9 +828,7 @@ static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue, 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); - EFX_BUG_ON_PARANOID(buffer->tsoh); + EFX_BUG_ON_PARANOID(buffer->flags); buffer->dma_addr = dma_addr; @@ -845,7 +838,8 @@ static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue, if (dma_len >= len) break; - buffer->len = dma_len; /* Don't set the other members */ + buffer->len = dma_len; + buffer->flags = EFX_TX_BUF_CONT; dma_addr += dma_len; len -= dma_len; } @@ -873,12 +867,11 @@ static void efx_tso_put_header(struct efx_tx_queue *tx_queue, 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); - EFX_BUG_ON_PARANOID(buffer->tsoh); + EFX_BUG_ON_PARANOID(buffer->flags); buffer->len = len; buffer->dma_addr = tsoh->dma_addr; buffer->tsoh = tsoh; + buffer->flags = EFX_TX_BUF_TSOH | EFX_TX_BUF_CONT; ++tx_queue->insert_count; } @@ -896,11 +889,11 @@ static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue) buffer = &tx_queue->buffer[tx_queue->insert_count & tx_queue->ptr_mask]; efx_tsoh_free(tx_queue, buffer); - EFX_BUG_ON_PARANOID(buffer->skb); + EFX_BUG_ON_PARANOID(buffer->flags & EFX_TX_BUF_SKB); if (buffer->unmap_len) { unmap_addr = (buffer->dma_addr + buffer->len - buffer->unmap_len); - if (buffer->unmap_single) + if (buffer->flags & EFX_TX_BUF_MAP_SINGLE) dma_unmap_single(&tx_queue->efx->pci_dev->dev, unmap_addr, buffer->unmap_len, DMA_TO_DEVICE); @@ -911,7 +904,7 @@ static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue) buffer->unmap_len = 0; } buffer->len = 0; - buffer->continuation = true; + buffer->flags = 0; } } @@ -938,7 +931,7 @@ static void tso_start(struct tso_state *st, const struct sk_buff *skb) st->out_len = skb->len - st->header_len; st->unmap_len = 0; - st->unmap_single = false; + st->dma_flags = 0; } static int tso_get_fragment(struct tso_state *st, struct efx_nic *efx, @@ -947,7 +940,7 @@ static int tso_get_fragment(struct tso_state *st, struct efx_nic *efx, st->unmap_addr = skb_frag_dma_map(&efx->pci_dev->dev, frag, 0, skb_frag_size(frag), DMA_TO_DEVICE); if (likely(!dma_mapping_error(&efx->pci_dev->dev, st->unmap_addr))) { - st->unmap_single = false; + st->dma_flags = 0; st->unmap_len = skb_frag_size(frag); st->in_len = skb_frag_size(frag); st->dma_addr = st->unmap_addr; @@ -965,7 +958,7 @@ static int tso_get_head_fragment(struct tso_state *st, struct efx_nic *efx, st->unmap_addr = dma_map_single(&efx->pci_dev->dev, skb->data + hl, len, DMA_TO_DEVICE); if (likely(!dma_mapping_error(&efx->pci_dev->dev, st->unmap_addr))) { - st->unmap_single = true; + st->dma_flags = EFX_TX_BUF_MAP_SINGLE; st->unmap_len = len; st->in_len = len; st->dma_addr = st->unmap_addr; @@ -990,7 +983,7 @@ static int tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue, struct tso_state *st) { struct efx_tx_buffer *buffer; - int n, end_of_packet, rc; + int n, rc; if (st->in_len == 0) return 0; @@ -1008,17 +1001,18 @@ static int tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue, rc = efx_tx_queue_insert(tx_queue, st->dma_addr, n, &buffer); if (likely(rc == 0)) { - if (st->out_len == 0) + if (st->out_len == 0) { /* Transfer ownership of the skb */ buffer->skb = skb; - - end_of_packet = st->out_len == 0 || st->packet_space == 0; - buffer->continuation = !end_of_packet; + buffer->flags = EFX_TX_BUF_SKB; + } else if (st->packet_space != 0) { + buffer->flags = EFX_TX_BUF_CONT; + } if (st->in_len == 0) { /* Transfer ownership of the DMA mapping */ buffer->unmap_len = st->unmap_len; - buffer->unmap_single = st->unmap_single; + buffer->flags |= st->dma_flags; st->unmap_len = 0; } } @@ -1195,7 +1189,7 @@ 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.unmap_len) { - if (state.unmap_single) + if (state.dma_flags & EFX_TX_BUF_MAP_SINGLE) dma_unmap_single(&efx->pci_dev->dev, state.unmap_addr, state.unmap_len, DMA_TO_DEVICE); else