+++ /dev/null
-From 8dc9a0888f4c8e27b25e48ff1b4bc2b3a845cc2d Mon Sep 17 00:00:00 2001
-From: Lorenzo Bianconi <lorenzo@kernel.org>
-Date: Sat, 19 Oct 2019 10:13:23 +0200
-Subject: [PATCH 3/7] net: mvneta: rely on build_skb in mvneta_rx_swbm poll
- routine
-
-Refactor mvneta_rx_swbm code introducing mvneta_swbm_rx_frame and
-mvneta_swbm_add_rx_fragment routines. Rely on build_skb in oreder to
-allocate skb since the previous patch introduced buffer recycling using
-the page_pool API.
-This patch fixes even an issue in the original driver where dma buffers
-are accessed before dma sync.
-mvneta driver can run on not cache coherent devices so it is
-necessary to sync DMA buffers before sending them to the device
-in order to avoid memory corruptions. Running perf analysis we can
-see a performance cost associated with this DMA-sync (anyway it is
-already there in the original driver code). In follow up patches we
-will add more logic to reduce DMA-sync as much as possible.
-
-Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
-Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
-Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
-Signed-off-by: David S. Miller <davem@davemloft.net>
----
- drivers/net/ethernet/marvell/mvneta.c | 185 +++++++++++++-------------
- 1 file changed, 95 insertions(+), 90 deletions(-)
-
---- a/drivers/net/ethernet/marvell/mvneta.c
-+++ b/drivers/net/ethernet/marvell/mvneta.c
-@@ -325,6 +325,11 @@
- ETH_HLEN + ETH_FCS_LEN, \
- cache_line_size())
-
-+#define MVNETA_SKB_PAD (SKB_DATA_ALIGN(sizeof(struct skb_shared_info) + \
-+ NET_SKB_PAD))
-+#define MVNETA_SKB_SIZE(len) (SKB_DATA_ALIGN(len) + MVNETA_SKB_PAD)
-+#define MVNETA_MAX_RX_BUF_SIZE (PAGE_SIZE - MVNETA_SKB_PAD)
-+
- #define IS_TSO_HEADER(txq, addr) \
- ((addr >= txq->tso_hdrs_phys) && \
- (addr < txq->tso_hdrs_phys + txq->size * TSO_HEADER_SIZE))
-@@ -650,7 +655,6 @@ static int txq_number = 8;
- static int rxq_def;
-
- static int rx_copybreak __read_mostly = 256;
--static int rx_header_size __read_mostly = 128;
-
- /* HW BM need that each port be identify by a unique ID */
- static int global_port_id;
-@@ -1842,7 +1846,7 @@ static int mvneta_rx_refill(struct mvnet
- phys_addr = page_pool_get_dma_addr(page) + pp->rx_offset_correction;
- dma_dir = page_pool_get_dma_dir(rxq->page_pool);
- dma_sync_single_for_device(pp->dev->dev.parent, phys_addr,
-- PAGE_SIZE, dma_dir);
-+ MVNETA_MAX_RX_BUF_SIZE, dma_dir);
- mvneta_rx_desc_fill(rx_desc, phys_addr, page, rxq);
-
- return 0;
-@@ -1960,30 +1964,102 @@ int mvneta_rx_refill_queue(struct mvneta
- return i;
- }
-
-+static int
-+mvneta_swbm_rx_frame(struct mvneta_port *pp,
-+ struct mvneta_rx_desc *rx_desc,
-+ struct mvneta_rx_queue *rxq,
-+ struct page *page)
-+{
-+ unsigned char *data = page_address(page);
-+ int data_len = -MVNETA_MH_SIZE, len;
-+ struct net_device *dev = pp->dev;
-+ enum dma_data_direction dma_dir;
-+
-+ if (MVNETA_SKB_SIZE(rx_desc->data_size) > PAGE_SIZE) {
-+ len = MVNETA_MAX_RX_BUF_SIZE;
-+ data_len += len;
-+ } else {
-+ len = rx_desc->data_size;
-+ data_len += len - ETH_FCS_LEN;
-+ }
-+
-+ dma_dir = page_pool_get_dma_dir(rxq->page_pool);
-+ dma_sync_single_for_cpu(dev->dev.parent,
-+ rx_desc->buf_phys_addr,
-+ len, dma_dir);
-+
-+ rxq->skb = build_skb(data, PAGE_SIZE);
-+ if (unlikely(!rxq->skb)) {
-+ netdev_err(dev,
-+ "Can't allocate skb on queue %d\n",
-+ rxq->id);
-+ dev->stats.rx_dropped++;
-+ rxq->skb_alloc_err++;
-+ return -ENOMEM;
-+ }
-+ page_pool_release_page(rxq->page_pool, page);
-+
-+ skb_reserve(rxq->skb, MVNETA_MH_SIZE + NET_SKB_PAD);
-+ skb_put(rxq->skb, data_len);
-+ mvneta_rx_csum(pp, rx_desc->status, rxq->skb);
-+
-+ rxq->left_size = rx_desc->data_size - len;
-+ rx_desc->buf_phys_addr = 0;
-+
-+ return 0;
-+}
-+
-+static void
-+mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
-+ struct mvneta_rx_desc *rx_desc,
-+ struct mvneta_rx_queue *rxq,
-+ struct page *page)
-+{
-+ struct net_device *dev = pp->dev;
-+ enum dma_data_direction dma_dir;
-+ int data_len, len;
-+
-+ if (rxq->left_size > MVNETA_MAX_RX_BUF_SIZE) {
-+ len = MVNETA_MAX_RX_BUF_SIZE;
-+ data_len = len;
-+ } else {
-+ len = rxq->left_size;
-+ data_len = len - ETH_FCS_LEN;
-+ }
-+ dma_dir = page_pool_get_dma_dir(rxq->page_pool);
-+ dma_sync_single_for_cpu(dev->dev.parent,
-+ rx_desc->buf_phys_addr,
-+ len, dma_dir);
-+ if (data_len > 0) {
-+ /* refill descriptor with new buffer later */
-+ skb_add_rx_frag(rxq->skb,
-+ skb_shinfo(rxq->skb)->nr_frags,
-+ page, NET_SKB_PAD, data_len,
-+ PAGE_SIZE);
-+ }
-+ page_pool_release_page(rxq->page_pool, page);
-+ rx_desc->buf_phys_addr = 0;
-+ rxq->left_size -= len;
-+}
-+
- /* Main rx processing when using software buffer management */
- static int mvneta_rx_swbm(struct napi_struct *napi,
- struct mvneta_port *pp, int budget,
- struct mvneta_rx_queue *rxq)
- {
-+ int rcvd_pkts = 0, rcvd_bytes = 0, rx_proc = 0;
- struct net_device *dev = pp->dev;
-- int rx_todo, rx_proc;
-- int refill = 0;
-- u32 rcvd_pkts = 0;
-- u32 rcvd_bytes = 0;
-+ int rx_todo, refill;
-
- /* Get number of received packets */
- rx_todo = mvneta_rxq_busy_desc_num_get(pp, rxq);
-- rx_proc = 0;
-
- /* Fairness NAPI loop */
-- while ((rcvd_pkts < budget) && (rx_proc < rx_todo)) {
-+ while (rx_proc < budget && rx_proc < rx_todo) {
- struct mvneta_rx_desc *rx_desc = mvneta_rxq_next_desc_get(rxq);
-+ u32 rx_status, index;
- unsigned char *data;
- struct page *page;
-- dma_addr_t phys_addr;
-- u32 rx_status, index;
-- int rx_bytes, skb_size, copy_size;
-- int frag_num, frag_size, frag_offset;
-
- index = rx_desc - rxq->descs;
- page = (struct page *)rxq->buf_virt_addr[index];
-@@ -1991,100 +2067,30 @@ static int mvneta_rx_swbm(struct napi_st
- /* Prefetch header */
- prefetch(data);
-
-- phys_addr = rx_desc->buf_phys_addr;
- rx_status = rx_desc->status;
- rx_proc++;
- rxq->refill_num++;
-
- if (rx_status & MVNETA_RXD_FIRST_DESC) {
-+ int err;
-+
- /* Check errors only for FIRST descriptor */
- if (rx_status & MVNETA_RXD_ERR_SUMMARY) {
- mvneta_rx_error(pp, rx_desc);
- /* leave the descriptor untouched */
- continue;
- }
-- rx_bytes = rx_desc->data_size -
-- (ETH_FCS_LEN + MVNETA_MH_SIZE);
--
-- /* Allocate small skb for each new packet */
-- skb_size = max(rx_copybreak, rx_header_size);
-- rxq->skb = netdev_alloc_skb_ip_align(dev, skb_size);
-- if (unlikely(!rxq->skb)) {
-- struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
--
-- netdev_err(dev,
-- "Can't allocate skb on queue %d\n",
-- rxq->id);
--
-- rxq->skb_alloc_err++;
-
-- u64_stats_update_begin(&stats->syncp);
-- stats->rx_dropped++;
-- u64_stats_update_end(&stats->syncp);
-+ err = mvneta_swbm_rx_frame(pp, rx_desc, rxq, page);
-+ if (err)
- continue;
-- }
-- copy_size = min(skb_size, rx_bytes);
--
-- /* Copy data from buffer to SKB, skip Marvell header */
-- memcpy(rxq->skb->data, data + MVNETA_MH_SIZE,
-- copy_size);
-- skb_put(rxq->skb, copy_size);
-- rxq->left_size = rx_bytes - copy_size;
--
-- mvneta_rx_csum(pp, rx_status, rxq->skb);
-- if (rxq->left_size == 0) {
-- int size = copy_size + MVNETA_MH_SIZE;
--
-- dma_sync_single_range_for_cpu(dev->dev.parent,
-- phys_addr, 0,
-- size,
-- DMA_FROM_DEVICE);
--
-- /* leave the descriptor and buffer untouched */
-- } else {
-- /* refill descriptor with new buffer later */
-- rx_desc->buf_phys_addr = 0;
--
-- frag_num = 0;
-- frag_offset = copy_size + MVNETA_MH_SIZE;
-- frag_size = min(rxq->left_size,
-- (int)(PAGE_SIZE - frag_offset));
-- skb_add_rx_frag(rxq->skb, frag_num, page,
-- frag_offset, frag_size,
-- PAGE_SIZE);
-- page_pool_release_page(rxq->page_pool, page);
-- rxq->left_size -= frag_size;
-- }
- } else {
-- /* Middle or Last descriptor */
- if (unlikely(!rxq->skb)) {
- pr_debug("no skb for rx_status 0x%x\n",
- rx_status);
- continue;
- }
-- if (!rxq->left_size) {
-- /* last descriptor has only FCS */
-- /* and can be discarded */
-- dma_sync_single_range_for_cpu(dev->dev.parent,
-- phys_addr, 0,
-- ETH_FCS_LEN,
-- DMA_FROM_DEVICE);
-- /* leave the descriptor and buffer untouched */
-- } else {
-- /* refill descriptor with new buffer later */
-- rx_desc->buf_phys_addr = 0;
--
-- frag_num = skb_shinfo(rxq->skb)->nr_frags;
-- frag_offset = 0;
-- frag_size = min(rxq->left_size,
-- (int)(PAGE_SIZE - frag_offset));
-- skb_add_rx_frag(rxq->skb, frag_num, page,
-- frag_offset, frag_size,
-- PAGE_SIZE);
--
-- page_pool_release_page(rxq->page_pool, page);
-- rxq->left_size -= frag_size;
-- }
-+ mvneta_swbm_add_rx_fragment(pp, rx_desc, rxq, page);
- } /* Middle or Last descriptor */
-
- if (!(rx_status & MVNETA_RXD_LAST_DESC))
-@@ -2109,7 +2115,6 @@ static int mvneta_rx_swbm(struct napi_st
-
- /* clean uncomplete skb pointer in queue */
- rxq->skb = NULL;
-- rxq->left_size = 0;
- }
-
- if (rcvd_pkts)
-@@ -2970,7 +2975,7 @@ static void mvneta_rxq_hw_init(struct mv
- /* Set Offset */
- mvneta_rxq_offset_set(pp, rxq, 0);
- mvneta_rxq_buf_size_set(pp, rxq, PAGE_SIZE < SZ_64K ?
-- PAGE_SIZE :
-+ MVNETA_MAX_RX_BUF_SIZE :
- MVNETA_RX_BUF_SIZE(pp->pkt_size));
- mvneta_rxq_bm_disable(pp, rxq);
- mvneta_rxq_fill(pp, rxq, rxq->size);
-@@ -4713,7 +4718,7 @@ static int mvneta_probe(struct platform_
- SET_NETDEV_DEV(dev, &pdev->dev);
-
- pp->id = global_port_id++;
-- pp->rx_offset_correction = 0; /* not relevant for SW BM */
-+ pp->rx_offset_correction = NET_SKB_PAD;
-
- /* Obtain access to BM resources if enabled and already initialized */
- bm_node = of_parse_phandle(dn, "buffer-manager", 0);
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