From 6dc8b74bf5c5a958136613ff773f6c770fbde2f2 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Sun, 20 Jan 2019 11:12:01 +0100 Subject: [PATCH] r8169: improve rx buffer allocation 8 years ago, as part of 6f0333b8fde4 ("r8169: use 50% less ram for RX ring"), the alignment requirement for rx buffers was silently changed from 8 bytes to 16 bytes. I found nothing explaining this, also the chip specs I have only mention an 8 byte requirement. AFAICS kmalloc_node() guarantees allocated memory to be at least "long long" aligned, what is 8 bytes on a 32 bit machine. So we can take this memory as-is and avoid some overhead by changing the alignment requirement back to 8 bytes. Signed-off-by: Heiner Kallweit Signed-off-by: David S. Miller --- drivers/net/ethernet/realtek/r8169.c | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c index e790a4116f1e..970c82694d4d 100644 --- a/drivers/net/ethernet/realtek/r8169.c +++ b/drivers/net/ethernet/realtek/r8169.c @@ -5659,11 +5659,6 @@ static inline void rtl8169_mark_to_asic(struct RxDesc *desc) desc->opts1 = cpu_to_le32(DescOwn | eor | R8169_RX_BUF_SIZE); } -static inline void *rtl8169_align(void *data) -{ - return (void *)ALIGN((long)data, 16); -} - static struct sk_buff *rtl8169_alloc_rx_data(struct rtl8169_private *tp, struct RxDesc *desc) { @@ -5676,15 +5671,13 @@ static struct sk_buff *rtl8169_alloc_rx_data(struct rtl8169_private *tp, if (!data) return NULL; - if (rtl8169_align(data) != data) { - kfree(data); - data = kmalloc_node(R8169_RX_BUF_SIZE + 15, GFP_KERNEL, node); - if (!data) - return NULL; + /* Memory should be properly aligned, but better check. */ + if (!IS_ALIGNED((unsigned long)data, 8)) { + netdev_err_once(tp->dev, "RX buffer not 8-byte-aligned\n"); + goto err_out; } - mapping = dma_map_single(d, rtl8169_align(data), R8169_RX_BUF_SIZE, - DMA_FROM_DEVICE); + mapping = dma_map_single(d, data, R8169_RX_BUF_SIZE, DMA_FROM_DEVICE); if (unlikely(dma_mapping_error(d, mapping))) { if (net_ratelimit()) netif_err(tp, drv, tp->dev, "Failed to map RX DMA!\n"); @@ -6290,7 +6283,6 @@ static struct sk_buff *rtl8169_try_rx_copy(void *data, struct sk_buff *skb; struct device *d = tp_to_dev(tp); - data = rtl8169_align(data); dma_sync_single_for_cpu(d, addr, pkt_size, DMA_FROM_DEVICE); prefetch(data); skb = napi_alloc_skb(&tp->napi, pkt_size);