diff options
Diffstat (limited to 'drivers/net/sfc/rx.c')
| -rw-r--r-- | drivers/net/sfc/rx.c | 90 |
1 files changed, 79 insertions, 11 deletions
diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c index 615a1fcd664..dfebd73cf86 100644 --- a/drivers/net/sfc/rx.c +++ b/drivers/net/sfc/rx.c @@ -82,9 +82,10 @@ static unsigned int rx_refill_limit = 95; * RX maximum head room required. * * This must be at least 1 to prevent overflow and at least 2 to allow - * pipelined receives. + * pipelined receives. Then a further 1 because efx_recycle_rx_buffer() + * might insert two buffers. */ -#define EFX_RXD_HEAD_ROOM 2 +#define EFX_RXD_HEAD_ROOM 3 static inline unsigned int efx_rx_buf_offset(struct efx_rx_buffer *buf) { @@ -250,6 +251,70 @@ static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue, efx_free_rx_buffer(rx_queue->efx, rx_buf); } +/* Attempt to resurrect the other receive buffer that used to share this page, + * which had previously been passed up to the kernel and freed. */ +static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue, + struct efx_rx_buffer *rx_buf) +{ + struct efx_rx_buffer *new_buf; + unsigned index; + + /* We could have recycled the 1st half, then refilled + * the queue, and now recycle the 2nd half. + * EFX_RXD_HEAD_ROOM ensures that there is always room + * to reinsert two buffers (once). */ + get_page(rx_buf->page); + + index = rx_queue->added_count & EFX_RXQ_MASK; + new_buf = efx_rx_buffer(rx_queue, index); + new_buf->dma_addr = rx_buf->dma_addr - (PAGE_SIZE >> 1); + new_buf->skb = NULL; + new_buf->page = rx_buf->page; + new_buf->data = rx_buf->data - (PAGE_SIZE >> 1); + new_buf->len = rx_buf->len; + ++rx_queue->added_count; +} + +/* Recycle the given rx buffer directly back into the rx_queue. There is + * always room to add this buffer, because we've just popped a buffer. */ +static void efx_recycle_rx_buffer(struct efx_channel *channel, + struct efx_rx_buffer *rx_buf) +{ + struct efx_nic *efx = channel->efx; + struct efx_rx_queue *rx_queue = &efx->rx_queue[channel->channel]; + struct efx_rx_buffer *new_buf; + unsigned index; + + if (rx_buf->page != NULL && efx->rx_buffer_len < (PAGE_SIZE >> 1)) { + if (efx_rx_buf_offset(rx_buf) & (PAGE_SIZE >> 1)) { + /* This is the 2nd half of a page split between two + * buffers, If page_count() is > 1 then the kernel + * is holding onto the previous buffer */ + if (page_count(rx_buf->page) != 1) { + efx_fini_rx_buffer(rx_queue, rx_buf); + return; + } + + efx_resurrect_rx_buffer(rx_queue, rx_buf); + } else { + /* Free the 1st buffer's reference on the page. If the + * 2nd buffer is also discarded, this buffer will be + * resurrected above */ + put_page(rx_buf->page); + rx_buf->page = NULL; + return; + } + } + + index = rx_queue->added_count & EFX_RXQ_MASK; + new_buf = efx_rx_buffer(rx_queue, index); + + memcpy(new_buf, rx_buf, sizeof(*new_buf)); + rx_buf->page = NULL; + rx_buf->skb = NULL; + ++rx_queue->added_count; +} + /** * efx_fast_push_rx_descriptors - push new RX descriptors quickly * @rx_queue: RX descriptor queue @@ -271,7 +336,7 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue) fill_level = (rx_queue->added_count - rx_queue->removed_count); EFX_BUG_ON_PARANOID(fill_level > EFX_RXQ_SIZE); if (fill_level >= rx_queue->fast_fill_trigger) - return; + goto out; /* Record minimum fill level */ if (unlikely(fill_level < rx_queue->min_fill)) { @@ -281,7 +346,7 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue) space = rx_queue->fast_fill_limit - fill_level; if (space < EFX_RX_BATCH) - return; + goto out; EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from" " level %d to level %d using %s allocation\n", @@ -306,8 +371,8 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue) rx_queue->added_count - rx_queue->removed_count); out: - /* Send write pointer to card. */ - efx_nic_notify_rx_desc(rx_queue); + if (rx_queue->notified_count != rx_queue->added_count) + efx_nic_notify_rx_desc(rx_queue); } void efx_rx_slow_fill(unsigned long context) @@ -418,6 +483,7 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, unsigned int len, bool checksummed, bool discard) { struct efx_nic *efx = rx_queue->efx; + struct efx_channel *channel = rx_queue->channel; struct efx_rx_buffer *rx_buf; bool leak_packet = false; @@ -445,12 +511,13 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, /* Discard packet, if instructed to do so */ if (unlikely(discard)) { if (unlikely(leak_packet)) - rx_queue->channel->n_skbuff_leaks++; + channel->n_skbuff_leaks++; else - /* We haven't called efx_unmap_rx_buffer yet, - * so fini the entire rx_buffer here */ - efx_fini_rx_buffer(rx_queue, rx_buf); - return; + efx_recycle_rx_buffer(channel, rx_buf); + + /* Don't hold off the previous receive */ + rx_buf = NULL; + goto out; } /* Release card resources - assumes all RX buffers consumed in-order @@ -467,6 +534,7 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index, * prefetched into cache. */ rx_buf->len = len; +out: if (rx_queue->channel->rx_pkt) __efx_rx_packet(rx_queue->channel, rx_queue->channel->rx_pkt, |