[PATCH v7 net-next 0/5] net: ethernet: ti: cpsw: Add XDP support

[PATCH v7 net-next 0/5] net: ethernet: ti: cpsw: Add XDP support

[Ivan Khoronzhuk]

This patchset adds XDP support for TI cpsw driver and base it on
page_pool allocator. It was verified on af_xdp socket drop,
af_xdp l2f, ebpf XDP_DROP, XDP_REDIRECT, XDP_PASS, XDP_TX.

It was verified with following configs enabled:
CONFIG_JIT=y
CONFIG_BPFILTER=y
CONFIG_BPF_SYSCALL=y
CONFIG_XDP_SOCKETS=y
CONFIG_BPF_EVENTS=y
CONFIG_HAVE_EBPF_JIT=y
CONFIG_BPF_JIT=y
CONFIG_CGROUP_BPF=y

Link on previous v6:
https://lkml.org/lkml/2019/7/3/243

Also regular tests with iperf2 were done in order to verify impact on
regular netstack performance, compared with base commit:
https://pastebin.com/JSMT0iZ4

v6..v7:
- rolled back to v4 solution but with small modification
- picked up patch:
  https://www.spinics.net/lists/netdev/msg583145.html
- added changes related to netsec fix and cpsw


v5..v6:
- do changes that is rx_dev while redirect/flush cycle is kept the same
- dropped net: ethernet: ti: davinci_cpdma: return handler status
- other changes desc in patches

v4..v5:
- added two plreliminary patches:
  net: ethernet: ti: davinci_cpdma: allow desc split while down
  net: ethernet: ti: cpsw_ethtool: allow res split while down
- added xdp alocator refcnt on xdp level, avoiding page pool refcnt
- moved flush status as separate argument for cpdma_chan_process
- reworked cpsw code according to last changes to allocator
- added missed statistic counter

v3..v4:
- added page pool user counter
- use same pool for ndevs in dual mac
- restructured page pool create/destroy according to the last changes in API

v2..v3:
- each rxq and ndev has its own page pool

v1..v2:
- combined xdp_xmit functions
- used page allocation w/o refcnt juggle
- unmapped page for skb netstack
- moved rxq/page pool allocation to open/close pair
- added several preliminary patches:
  net: page_pool: add helper function to retrieve dma addresses
  net: page_pool: add helper function to unmap dma addresses
  net: ethernet: ti: cpsw: use cpsw as drv data
  net: ethernet: ti: cpsw_ethtool: simplify slave loops

Ivan Khoronzhuk (5):
  net: core: page_pool: add user refcnt and reintroduce
    page_pool_destroy
  net: ethernet: ti: davinci_cpdma: add dma mapped submit
  net: ethernet: ti: davinci_cpdma: allow desc split while down
  net: ethernet: ti: cpsw_ethtool: allow res split while down
  net: ethernet: ti: cpsw: add XDP support

 .../net/ethernet/mellanox/mlx5/core/en_main.c |   4 +-
 drivers/net/ethernet/socionext/netsec.c       |   8 +-
 drivers/net/ethernet/ti/Kconfig               |   1 +
 drivers/net/ethernet/ti/cpsw.c                | 502 ++++++++++++++++--
 drivers/net/ethernet/ti/cpsw_ethtool.c        |  57 +-
 drivers/net/ethernet/ti/cpsw_priv.h           |   7 +
 drivers/net/ethernet/ti/davinci_cpdma.c       | 106 +++-
 drivers/net/ethernet/ti/davinci_cpdma.h       |   7 +-
 include/net/page_pool.h                       |  25 +
 net/core/page_pool.c                          |   8 +
 net/core/xdp.c                                |   3 +
 11 files changed, 640 insertions(+), 88 deletions(-)

-- 
2.17.1

[PATCH v7 net-next 1/5] net: core: page_pool: add user refcnt and reintroduce page_pool_destroy

[Ivan Khoronzhuk]

Jesper recently removed page_pool_destroy() (from driver invocation)
and moved shutdown and free of page_pool into xdp_rxq_info_unreg(),
in-order to handle in-flight packets/pages. This created an asymmetry
in drivers create/destroy pairs.

This patch reintroduce page_pool_destroy and add page_pool user
refcnt. This serves the purpose to simplify drivers error handling as
driver now drivers always calls page_pool_destroy() and don't need to
track if xdp_rxq_info_reg_mem_model() was unsuccessful.

This could be used for a special cases where a single RX-queue (with a
single page_pool) provides packets for two net_device'es, and thus
needs to register the same page_pool twice with two xdp_rxq_info
structures.

This patch is primarily to ease API usage for drivers. The recently
merged netsec driver, actually have a bug in this area, which is
solved by this API change.

This patch is a modified version of Ivan Khoronzhu's original patch.

Link: https://lore.kernel.org/netdev/20190625175948.24771-2-ivan.khoronzhuk@linaro.org/
Fixes: 5c67bf0ec4d0 ("net: netsec: Use page_pool API")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 .../net/ethernet/mellanox/mlx5/core/en_main.c |  4 +--
 drivers/net/ethernet/socionext/netsec.c       |  8 ++----
 include/net/page_pool.h                       | 25 +++++++++++++++++++
 net/core/page_pool.c                          |  8 ++++++
 net/core/xdp.c                                |  3 +++
 5 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 2f9093ba82aa..ac882b2341d0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -575,8 +575,6 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
 		}
 		err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 						 MEM_TYPE_PAGE_POOL, rq->page_pool);
-		if (err)
-			page_pool_free(rq->page_pool);
 	}
 	if (err)
 		goto err_free;
@@ -644,6 +642,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
 	if (rq->xdp_prog)
 		bpf_prog_put(rq->xdp_prog);
 	xdp_rxq_info_unreg(&rq->xdp_rxq);
+	page_pool_destroy(rq->page_pool);
 	mlx5_wq_destroy(&rq->wq_ctrl);
 
 	return err;
@@ -678,6 +677,7 @@ static void mlx5e_free_rq(struct mlx5e_rq *rq)
 	}
 
 	xdp_rxq_info_unreg(&rq->xdp_rxq);
+	page_pool_destroy(rq->page_pool);
 	mlx5_wq_destroy(&rq->wq_ctrl);
 }
 
diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
index 5544a722543f..43ab0ce90704 100644
--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -1210,15 +1210,11 @@ static void netsec_uninit_pkt_dring(struct netsec_priv *priv, int id)
 		}
 	}
 
-	/* Rx is currently using page_pool
-	 * since the pool is created during netsec_setup_rx_dring(), we need to
-	 * free the pool manually if the registration failed
-	 */
+	/* Rx is currently using page_pool */
 	if (id == NETSEC_RING_RX) {
 		if (xdp_rxq_info_is_reg(&dring->xdp_rxq))
 			xdp_rxq_info_unreg(&dring->xdp_rxq);
-		else
-			page_pool_free(dring->page_pool);
+		page_pool_destroy(dring->page_pool);
 	}
 
 	memset(dring->desc, 0, sizeof(struct netsec_desc) * DESC_NUM);
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index ee9c871d2043..2cbcdbdec254 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -101,6 +101,12 @@ struct page_pool {
 	struct ptr_ring ring;
 
 	atomic_t pages_state_release_cnt;
+
+	/* A page_pool is strictly tied to a single RX-queue being
+	 * protected by NAPI, due to above pp_alloc_cache. This
+	 * refcnt serves purpose is to simplify drivers error handling.
+	 */
+	refcount_t user_cnt;
 };
 
 struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
@@ -134,6 +140,15 @@ static inline void page_pool_free(struct page_pool *pool)
 #endif
 }
 
+/* Drivers use this instead of page_pool_free */
+static inline void page_pool_destroy(struct page_pool *pool)
+{
+	if (!pool)
+		return;
+
+	page_pool_free(pool);
+}
+
 /* Never call this directly, use helpers below */
 void __page_pool_put_page(struct page_pool *pool,
 			  struct page *page, bool allow_direct);
@@ -201,4 +216,14 @@ static inline bool is_page_pool_compiled_in(void)
 #endif
 }
 
+static inline void page_pool_get(struct page_pool *pool)
+{
+	refcount_inc(&pool->user_cnt);
+}
+
+static inline bool page_pool_put(struct page_pool *pool)
+{
+	return refcount_dec_and_test(&pool->user_cnt);
+}
+
 #endif /* _NET_PAGE_POOL_H */
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index b366f59885c1..3272dc7a8c81 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -49,6 +49,9 @@ static int page_pool_init(struct page_pool *pool,
 
 	atomic_set(&pool->pages_state_release_cnt, 0);
 
+	/* Driver calling page_pool_create() also call page_pool_destroy() */
+	refcount_set(&pool->user_cnt, 1);
+
 	if (pool->p.flags & PP_FLAG_DMA_MAP)
 		get_device(pool->p.dev);
 
@@ -70,6 +73,7 @@ struct page_pool *page_pool_create(const struct page_pool_params *params)
 		kfree(pool);
 		return ERR_PTR(err);
 	}
+
 	return pool;
 }
 EXPORT_SYMBOL(page_pool_create);
@@ -356,6 +360,10 @@ static void __warn_in_flight(struct page_pool *pool)
 
 void __page_pool_free(struct page_pool *pool)
 {
+	/* Only last user actually free/release resources */
+	if (!page_pool_put(pool))
+		return;
+
 	WARN(pool->alloc.count, "API usage violation");
 	WARN(!ptr_ring_empty(&pool->ring), "ptr_ring is not empty");
 
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 829377cc83db..d7bf62ffbb5e 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -370,6 +370,9 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
 		goto err;
 	}
 
+	if (type == MEM_TYPE_PAGE_POOL)
+		page_pool_get(xdp_alloc->page_pool);
+
 	mutex_unlock(&mem_id_lock);
 
 	trace_mem_connect(xdp_alloc, xdp_rxq);
-- 
2.17.1

[PATCH v7 net-next 2/5] net: ethernet: ti: davinci_cpdma: add dma mapped submit

[Ivan Khoronzhuk]

In case if dma mapped packet needs to be sent, like with XDP
page pool, the "mapped" submit can be used. This patch adds dma
mapped submit based on regular one.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 drivers/net/ethernet/ti/davinci_cpdma.c | 89 ++++++++++++++++++++++---
 drivers/net/ethernet/ti/davinci_cpdma.h |  4 ++
 2 files changed, 83 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index 5cf1758d425b..8da46394c0e7 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -139,6 +139,7 @@ struct submit_info {
 	int directed;
 	void *token;
 	void *data;
+	int flags;
 	int len;
 };
 
@@ -184,6 +185,8 @@ static struct cpdma_control_info controls[] = {
 				 (directed << CPDMA_TO_PORT_SHIFT));	\
 	} while (0)
 
+#define CPDMA_DMA_EXT_MAP		BIT(16)
+
 static void cpdma_desc_pool_destroy(struct cpdma_ctlr *ctlr)
 {
 	struct cpdma_desc_pool *pool = ctlr->pool;
@@ -1015,6 +1018,7 @@ static int cpdma_chan_submit_si(struct submit_info *si)
 	struct cpdma_chan		*chan = si->chan;
 	struct cpdma_ctlr		*ctlr = chan->ctlr;
 	int				len = si->len;
+	int				swlen = len;
 	struct cpdma_desc __iomem	*desc;
 	dma_addr_t			buffer;
 	u32				mode;
@@ -1036,16 +1040,22 @@ static int cpdma_chan_submit_si(struct submit_info *si)
 		chan->stats.runt_transmit_buff++;
 	}
 
-	buffer = dma_map_single(ctlr->dev, si->data, len, chan->dir);
-	ret = dma_mapping_error(ctlr->dev, buffer);
-	if (ret) {
-		cpdma_desc_free(ctlr->pool, desc, 1);
-		return -EINVAL;
-	}
-
 	mode = CPDMA_DESC_OWNER | CPDMA_DESC_SOP | CPDMA_DESC_EOP;
 	cpdma_desc_to_port(chan, mode, si->directed);
 
+	if (si->flags & CPDMA_DMA_EXT_MAP) {
+		buffer = (u32)si->data;
+		dma_sync_single_for_device(ctlr->dev, buffer, len, chan->dir);
+		swlen |= CPDMA_DMA_EXT_MAP;
+	} else {
+		buffer = dma_map_single(ctlr->dev, si->data, len, chan->dir);
+		ret = dma_mapping_error(ctlr->dev, buffer);
+		if (ret) {
+			cpdma_desc_free(ctlr->pool, desc, 1);
+			return -EINVAL;
+		}
+	}
+
 	/* Relaxed IO accessors can be used here as there is read barrier
 	 * at the end of write sequence.
 	 */
@@ -1055,7 +1065,7 @@ static int cpdma_chan_submit_si(struct submit_info *si)
 	writel_relaxed(mode | len, &desc->hw_mode);
 	writel_relaxed((uintptr_t)si->token, &desc->sw_token);
 	writel_relaxed(buffer, &desc->sw_buffer);
-	writel_relaxed(len, &desc->sw_len);
+	writel_relaxed(swlen, &desc->sw_len);
 	desc_read(desc, sw_len);
 
 	__cpdma_chan_submit(chan, desc);
@@ -1079,6 +1089,32 @@ int cpdma_chan_idle_submit(struct cpdma_chan *chan, void *token, void *data,
 	si.data = data;
 	si.len = len;
 	si.directed = directed;
+	si.flags = 0;
+
+	spin_lock_irqsave(&chan->lock, flags);
+	if (chan->state == CPDMA_STATE_TEARDOWN) {
+		spin_unlock_irqrestore(&chan->lock, flags);
+		return -EINVAL;
+	}
+
+	ret = cpdma_chan_submit_si(&si);
+	spin_unlock_irqrestore(&chan->lock, flags);
+	return ret;
+}
+
+int cpdma_chan_idle_submit_mapped(struct cpdma_chan *chan, void *token,
+				  dma_addr_t data, int len, int directed)
+{
+	struct submit_info si;
+	unsigned long flags;
+	int ret;
+
+	si.chan = chan;
+	si.token = token;
+	si.data = (void *)(u32)data;
+	si.len = len;
+	si.directed = directed;
+	si.flags = CPDMA_DMA_EXT_MAP;
 
 	spin_lock_irqsave(&chan->lock, flags);
 	if (chan->state == CPDMA_STATE_TEARDOWN) {
@@ -1103,6 +1139,32 @@ int cpdma_chan_submit(struct cpdma_chan *chan, void *token, void *data,
 	si.data = data;
 	si.len = len;
 	si.directed = directed;
+	si.flags = 0;
+
+	spin_lock_irqsave(&chan->lock, flags);
+	if (chan->state != CPDMA_STATE_ACTIVE) {
+		spin_unlock_irqrestore(&chan->lock, flags);
+		return -EINVAL;
+	}
+
+	ret = cpdma_chan_submit_si(&si);
+	spin_unlock_irqrestore(&chan->lock, flags);
+	return ret;
+}
+
+int cpdma_chan_submit_mapped(struct cpdma_chan *chan, void *token,
+			     dma_addr_t data, int len, int directed)
+{
+	struct submit_info si;
+	unsigned long flags;
+	int ret;
+
+	si.chan = chan;
+	si.token = token;
+	si.data = (void *)(u32)data;
+	si.len = len;
+	si.directed = directed;
+	si.flags = CPDMA_DMA_EXT_MAP;
 
 	spin_lock_irqsave(&chan->lock, flags);
 	if (chan->state != CPDMA_STATE_ACTIVE) {
@@ -1140,10 +1202,17 @@ static void __cpdma_chan_free(struct cpdma_chan *chan,
 	uintptr_t			token;
 
 	token      = desc_read(desc, sw_token);
-	buff_dma   = desc_read(desc, sw_buffer);
 	origlen    = desc_read(desc, sw_len);
 
-	dma_unmap_single(ctlr->dev, buff_dma, origlen, chan->dir);
+	buff_dma   = desc_read(desc, sw_buffer);
+	if (origlen & CPDMA_DMA_EXT_MAP) {
+		origlen &= ~CPDMA_DMA_EXT_MAP;
+		dma_sync_single_for_cpu(ctlr->dev, buff_dma, origlen,
+					chan->dir);
+	} else {
+		dma_unmap_single(ctlr->dev, buff_dma, origlen, chan->dir);
+	}
+
 	cpdma_desc_free(pool, desc, 1);
 	(*chan->handler)((void *)token, outlen, status);
 }
diff --git a/drivers/net/ethernet/ti/davinci_cpdma.h b/drivers/net/ethernet/ti/davinci_cpdma.h
index 9343c8c73c1b..0271a20c2e09 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.h
+++ b/drivers/net/ethernet/ti/davinci_cpdma.h
@@ -77,8 +77,12 @@ int cpdma_chan_stop(struct cpdma_chan *chan);
 
 int cpdma_chan_get_stats(struct cpdma_chan *chan,
 			 struct cpdma_chan_stats *stats);
+int cpdma_chan_submit_mapped(struct cpdma_chan *chan, void *token,
+			     dma_addr_t data, int len, int directed);
 int cpdma_chan_submit(struct cpdma_chan *chan, void *token, void *data,
 		      int len, int directed);
+int cpdma_chan_idle_submit_mapped(struct cpdma_chan *chan, void *token,
+				  dma_addr_t data, int len, int directed);
 int cpdma_chan_idle_submit(struct cpdma_chan *chan, void *token, void *data,
 			   int len, int directed);
 int cpdma_chan_process(struct cpdma_chan *chan, int quota);
-- 
2.17.1

[PATCH v7 net-next 3/5] net: ethernet: ti: davinci_cpdma: allow desc split while down

[Ivan Khoronzhuk]

That's possible to set ring params while interfaces are down. When
interface gets up it uses number of descs to fill rx queue and on
later on changes to create rx pools. Usually, this resplit can happen
after phy is up, but it can be needed before this, so allow it to
happen while setting number of rx descs, when interfaces are down.
Also, if no dependency on intf state, move it to cpdma layer, where
it should be.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 drivers/net/ethernet/ti/cpsw_ethtool.c  | 17 +++++++++++------
 drivers/net/ethernet/ti/davinci_cpdma.c | 17 ++++++++++++++++-
 drivers/net/ethernet/ti/davinci_cpdma.h |  3 +--
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpsw_ethtool.c b/drivers/net/ethernet/ti/cpsw_ethtool.c
index f60dc1dfc443..c477e6b620d6 100644
--- a/drivers/net/ethernet/ti/cpsw_ethtool.c
+++ b/drivers/net/ethernet/ti/cpsw_ethtool.c
@@ -650,7 +650,7 @@ int cpsw_set_ringparam(struct net_device *ndev,
 {
 	struct cpsw_priv *priv = netdev_priv(ndev);
 	struct cpsw_common *cpsw = priv->cpsw;
-	int ret;
+	int descs_num, ret;
 
 	/* ignore ering->tx_pending - only rx_pending adjustment is supported */
 
@@ -659,20 +659,25 @@ int cpsw_set_ringparam(struct net_device *ndev,
 	    ering->rx_pending > (cpsw->descs_pool_size - CPSW_MAX_QUEUES))
 		return -EINVAL;
 
-	if (ering->rx_pending == cpdma_get_num_rx_descs(cpsw->dma))
+	descs_num = cpdma_get_num_rx_descs(cpsw->dma);
+	if (ering->rx_pending == descs_num)
 		return 0;
 
 	cpsw_suspend_data_pass(ndev);
 
-	cpdma_set_num_rx_descs(cpsw->dma, ering->rx_pending);
+	ret = cpdma_set_num_rx_descs(cpsw->dma, ering->rx_pending);
+	if (ret) {
+		if (cpsw_resume_data_pass(ndev))
+			goto err;
 
-	if (cpsw->usage_count)
-		cpdma_chan_split_pool(cpsw->dma);
+		return ret;
+	}
 
 	ret = cpsw_resume_data_pass(ndev);
 	if (!ret)
 		return 0;
-
+err:
+	cpdma_set_num_rx_descs(cpsw->dma, descs_num);
 	dev_err(cpsw->dev, "cannot set ring params, closing device\n");
 	dev_close(ndev);
 	return ret;
diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index 8da46394c0e7..a3b6aeb4e935 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -1423,8 +1423,23 @@ int cpdma_get_num_tx_descs(struct cpdma_ctlr *ctlr)
 	return ctlr->num_tx_desc;
 }
 
-void cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc)
+int cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc)
 {
+	unsigned long flags;
+	int temp, ret;
+
+	spin_lock_irqsave(&ctlr->lock, flags);
+
+	temp = ctlr->num_rx_desc;
 	ctlr->num_rx_desc = num_rx_desc;
 	ctlr->num_tx_desc = ctlr->pool->num_desc - ctlr->num_rx_desc;
+	ret = cpdma_chan_split_pool(ctlr);
+	if (ret) {
+		ctlr->num_rx_desc = temp;
+		ctlr->num_tx_desc = ctlr->pool->num_desc - ctlr->num_rx_desc;
+	}
+
+	spin_unlock_irqrestore(&ctlr->lock, flags);
+
+	return ret;
 }
diff --git a/drivers/net/ethernet/ti/davinci_cpdma.h b/drivers/net/ethernet/ti/davinci_cpdma.h
index 0271a20c2e09..d3cfe234d16a 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.h
+++ b/drivers/net/ethernet/ti/davinci_cpdma.h
@@ -116,8 +116,7 @@ enum cpdma_control {
 int cpdma_control_get(struct cpdma_ctlr *ctlr, int control);
 int cpdma_control_set(struct cpdma_ctlr *ctlr, int control, int value);
 int cpdma_get_num_rx_descs(struct cpdma_ctlr *ctlr);
-void cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc);
+int cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc);
 int cpdma_get_num_tx_descs(struct cpdma_ctlr *ctlr);
-int cpdma_chan_split_pool(struct cpdma_ctlr *ctlr);
 
 #endif
-- 
2.17.1

[PATCH v7 net-next 4/5] net: ethernet: ti: cpsw_ethtool: allow res split while down

[Ivan Khoronzhuk]

That's possible to set channel num while interfaces are down. When
interface gets up it should resplit budget. This resplit can happen
after phy is up but only if speed is changed, so should be set before
this, for this allow it to happen while changing number of channels,
when interfaces are down.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 drivers/net/ethernet/ti/cpsw_ethtool.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpsw_ethtool.c b/drivers/net/ethernet/ti/cpsw_ethtool.c
index c477e6b620d6..e4d7185fde49 100644
--- a/drivers/net/ethernet/ti/cpsw_ethtool.c
+++ b/drivers/net/ethernet/ti/cpsw_ethtool.c
@@ -620,8 +620,7 @@ int cpsw_set_channels_common(struct net_device *ndev,
 		}
 	}
 
-	if (cpsw->usage_count)
-		cpsw_split_res(cpsw);
+	cpsw_split_res(cpsw);
 
 	ret = cpsw_resume_data_pass(ndev);
 	if (!ret)
-- 
2.17.1

[PATCH v7 net-next 5/5] net: ethernet: ti: cpsw: add XDP support

[Ivan Khoronzhuk]

Add XDP support based on rx page_pool allocator, one frame per page.
Page pool allocator is used with assumption that only one rx_handler
is running simultaneously. DMA map/unmap is reused from page pool
despite there is no need to map whole page.

Due to specific of cpsw, the same TX/RX handler can be used by 2
network devices, so special fields in buffer are added to identify
an interface the frame is destined to. Thus XDP works for both
interfaces, that allows to test xdp redirect between two interfaces
easily. Aslo, each rx queue have own page pools, but common for both
netdevs.

XDP prog is common for all channels till appropriate changes are added
in XDP infrastructure. Also, once page_pool recycling becomes part of
skb netstack some simplifications can be added, like removing
page_pool_release_page() before skb receive.

In order to keep rx_dev while redirect, that can be somehow used in
future, do flush in rx_handler, that allows to keep rx dev the same
while reidrect. It allows to conform with tracing rx_dev pointed
by Jesper.

Also, there is probability, that XDP generic code can be extended to
support multi ndev drivers like this one, using same rx queue for
several ndevs, based on switchdev for instance or else. In this case,
driver can be modified like exposed here:
https://lkml.org/lkml/2019/7/3/243

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 drivers/net/ethernet/ti/Kconfig        |   1 +
 drivers/net/ethernet/ti/cpsw.c         | 502 ++++++++++++++++++++++---
 drivers/net/ethernet/ti/cpsw_ethtool.c |  37 +-
 drivers/net/ethernet/ti/cpsw_priv.h    |   7 +
 4 files changed, 488 insertions(+), 59 deletions(-)

diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
index a800d3417411..834afca3a019 100644
--- a/drivers/net/ethernet/ti/Kconfig
+++ b/drivers/net/ethernet/ti/Kconfig
@@ -50,6 +50,7 @@ config TI_CPSW
 	depends on ARCH_DAVINCI || ARCH_OMAP2PLUS || COMPILE_TEST
 	select TI_DAVINCI_MDIO
 	select MFD_SYSCON
+	select PAGE_POOL
 	select REGMAP
 	---help---
 	  This driver supports TI's CPSW Ethernet Switch.
diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 32b7b3b74a6b..c17bb9381116 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -31,6 +31,10 @@
 #include <linux/if_vlan.h>
 #include <linux/kmemleak.h>
 #include <linux/sys_soc.h>
+#include <net/page_pool.h>
+#include <linux/bpf.h>
+#include <linux/bpf_trace.h>
+#include <linux/filter.h>
 
 #include <linux/pinctrl/consumer.h>
 #include <net/pkt_cls.h>
@@ -60,6 +64,10 @@ static int descs_pool_size = CPSW_CPDMA_DESCS_POOL_SIZE_DEFAULT;
 module_param(descs_pool_size, int, 0444);
 MODULE_PARM_DESC(descs_pool_size, "Number of CPDMA CPPI descriptors in pool");
 
+/* The buf includes headroom compatible with both skb and xdpf */
+#define CPSW_HEADROOM_NA (max(XDP_PACKET_HEADROOM, NET_SKB_PAD) + NET_IP_ALIGN)
+#define CPSW_HEADROOM  ALIGN(CPSW_HEADROOM_NA, sizeof(long))
+
 #define for_each_slave(priv, func, arg...)				\
 	do {								\
 		struct cpsw_slave *slave;				\
@@ -74,6 +82,11 @@ MODULE_PARM_DESC(descs_pool_size, "Number of CPDMA CPPI descriptors in pool");
 				(func)(slave++, ##arg);			\
 	} while (0)
 
+#define CPSW_XMETA_OFFSET	ALIGN(sizeof(struct xdp_frame), sizeof(long))
+
+#define CPSW_XDP_CONSUMED		1
+#define CPSW_XDP_PASS			0
+
 static int cpsw_ndo_vlan_rx_add_vid(struct net_device *ndev,
 				    __be16 proto, u16 vid);
 
@@ -337,24 +350,58 @@ void cpsw_intr_disable(struct cpsw_common *cpsw)
 	return;
 }
 
+static int cpsw_is_xdpf_handle(void *handle)
+{
+	return (unsigned long)handle & BIT(0);
+}
+
+static void *cpsw_xdpf_to_handle(struct xdp_frame *xdpf)
+{
+	return (void *)((unsigned long)xdpf | BIT(0));
+}
+
+static struct xdp_frame *cpsw_handle_to_xdpf(void *handle)
+{
+	return (struct xdp_frame *)((unsigned long)handle & ~BIT(0));
+}
+
+struct __aligned(sizeof(long)) cpsw_meta_xdp {
+	struct net_device *ndev;
+	int ch;
+};
+
 void cpsw_tx_handler(void *token, int len, int status)
 {
+	struct cpsw_meta_xdp	*xmeta;
+	struct xdp_frame	*xdpf;
+	struct net_device	*ndev;
 	struct netdev_queue	*txq;
-	struct sk_buff		*skb = token;
-	struct net_device	*ndev = skb->dev;
-	struct cpsw_common	*cpsw = ndev_to_cpsw(ndev);
+	struct sk_buff		*skb;
+	int			ch;
+
+	if (cpsw_is_xdpf_handle(token)) {
+		xdpf = cpsw_handle_to_xdpf(token);
+		xmeta = (void *)xdpf + CPSW_XMETA_OFFSET;
+		ndev = xmeta->ndev;
+		ch = xmeta->ch;
+		xdp_return_frame(xdpf);
+	} else {
+		skb = token;
+		ndev = skb->dev;
+		ch = skb_get_queue_mapping(skb);
+		cpts_tx_timestamp(ndev_to_cpsw(ndev)->cpts, skb);
+		dev_kfree_skb_any(skb);
+	}
 
 	/* Check whether the queue is stopped due to stalled tx dma, if the
 	 * queue is stopped then start the queue as we have free desc for tx
 	 */
-	txq = netdev_get_tx_queue(ndev, skb_get_queue_mapping(skb));
+	txq = netdev_get_tx_queue(ndev, ch);
 	if (unlikely(netif_tx_queue_stopped(txq)))
 		netif_tx_wake_queue(txq);
 
-	cpts_tx_timestamp(cpsw->cpts, skb);
 	ndev->stats.tx_packets++;
 	ndev->stats.tx_bytes += len;
-	dev_kfree_skb_any(skb);
 }
 
 static void cpsw_rx_vlan_encap(struct sk_buff *skb)
@@ -400,24 +447,252 @@ static void cpsw_rx_vlan_encap(struct sk_buff *skb)
 	}
 }
 
+static int cpsw_xdp_tx_frame(struct cpsw_priv *priv, struct xdp_frame *xdpf,
+			     struct page *page)
+{
+	struct cpsw_common *cpsw = priv->cpsw;
+	struct cpsw_meta_xdp *xmeta;
+	struct cpdma_chan *txch;
+	dma_addr_t dma;
+	int ret, port;
+
+	xmeta = (void *)xdpf + CPSW_XMETA_OFFSET;
+	xmeta->ndev = priv->ndev;
+	xmeta->ch = 0;
+	txch = cpsw->txv[0].ch;
+
+	port = priv->emac_port + cpsw->data.dual_emac;
+	if (page) {
+		dma = page_pool_get_dma_addr(page);
+		dma += xdpf->data - (void *)xdpf;
+		ret = cpdma_chan_submit_mapped(txch, cpsw_xdpf_to_handle(xdpf),
+					       dma, xdpf->len, port);
+	} else {
+		if (sizeof(*xmeta) > xdpf->headroom) {
+			xdp_return_frame_rx_napi(xdpf);
+			return -EINVAL;
+		}
+
+		ret = cpdma_chan_submit(txch, cpsw_xdpf_to_handle(xdpf),
+					xdpf->data, xdpf->len, port);
+	}
+
+	if (ret) {
+		priv->ndev->stats.tx_dropped++;
+		xdp_return_frame_rx_napi(xdpf);
+	}
+
+	return ret;
+}
+
+static int cpsw_run_xdp(struct cpsw_priv *priv, int ch, struct xdp_buff *xdp,
+			struct page *page)
+{
+	struct cpsw_common *cpsw = priv->cpsw;
+	struct net_device *ndev = priv->ndev;
+	int ret = CPSW_XDP_CONSUMED;
+	struct xdp_frame *xdpf;
+	struct bpf_prog *prog;
+	u32 act;
+
+	rcu_read_lock();
+
+	prog = READ_ONCE(priv->xdp_prog);
+	if (!prog) {
+		ret = CPSW_XDP_PASS;
+		goto out;
+	}
+
+	act = bpf_prog_run_xdp(prog, xdp);
+	switch (act) {
+	case XDP_PASS:
+		ret = CPSW_XDP_PASS;
+		break;
+	case XDP_TX:
+		xdpf = convert_to_xdp_frame(xdp);
+		if (unlikely(!xdpf))
+			goto drop;
+
+		cpsw_xdp_tx_frame(priv, xdpf, page);
+		break;
+	case XDP_REDIRECT:
+		if (xdp_do_redirect(ndev, xdp, prog))
+			goto drop;
+
+		/*  Have to flush here, per packet, instead of doing it in bulk
+		 *  at the end of the napi handler. The RX devices on this
+		 *  particular hardware is sharing a common queue, so the
+		 *  incoming device might change per packet.
+		 */
+		xdp_do_flush_map();
+		break;
+	default:
+		bpf_warn_invalid_xdp_action(act);
+		/* fall through */
+	case XDP_ABORTED:
+		trace_xdp_exception(ndev, prog, act);
+		/* fall through -- handle aborts by dropping packet */
+	case XDP_DROP:
+		goto drop;
+	}
+out:
+	rcu_read_unlock();
+	return ret;
+drop:
+	rcu_read_unlock();
+	page_pool_recycle_direct(cpsw->page_pool[ch], page);
+	return ret;
+}
+
+static unsigned int cpsw_rxbuf_total_len(unsigned int len)
+{
+	len += CPSW_HEADROOM;
+	len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+
+	return SKB_DATA_ALIGN(len);
+}
+
+static struct page_pool *cpsw_create_page_pool(struct cpsw_common *cpsw,
+					       int size)
+{
+	struct page_pool_params pp_params;
+	struct page_pool *pool;
+
+	pp_params.order = 0;
+	pp_params.flags = PP_FLAG_DMA_MAP;
+	pp_params.pool_size = size;
+	pp_params.nid = NUMA_NO_NODE;
+	pp_params.dma_dir = DMA_BIDIRECTIONAL;
+	pp_params.dev = cpsw->dev;
+
+	pool = page_pool_create(&pp_params);
+	if (IS_ERR(pool))
+		dev_err(cpsw->dev, "cannot create rx page pool\n");
+
+	return pool;
+}
+
+static int cpsw_ndev_create_xdp_rxq(struct cpsw_priv *priv, int ch)
+{
+	struct cpsw_common *cpsw = priv->cpsw;
+	struct xdp_rxq_info *rxq;
+	struct page_pool *pool;
+	int ret;
+
+	pool = cpsw->page_pool[ch];
+	rxq = &priv->xdp_rxq[ch];
+
+	ret = xdp_rxq_info_reg(rxq, priv->ndev, ch);
+	if (ret)
+		return ret;
+
+	ret = xdp_rxq_info_reg_mem_model(rxq, MEM_TYPE_PAGE_POOL, pool);
+	if (ret)
+		xdp_rxq_info_unreg(rxq);
+
+	return ret;
+}
+
+static void cpsw_ndev_destroy_xdp_rxq(struct cpsw_priv *priv, int ch)
+{
+	struct xdp_rxq_info *rxq = &priv->xdp_rxq[ch];
+
+	if (!xdp_rxq_info_is_reg(rxq))
+		return;
+
+	xdp_rxq_info_unreg(rxq);
+}
+
+static int cpsw_create_rx_pool(struct cpsw_common *cpsw, int ch)
+{
+	struct page_pool *pool;
+	int ret = 0, pool_size;
+
+	pool_size = cpdma_chan_get_rx_buf_num(cpsw->rxv[ch].ch);
+	pool = cpsw_create_page_pool(cpsw, pool_size);
+	if (IS_ERR(pool))
+		ret = PTR_ERR(pool);
+	else
+		cpsw->page_pool[ch] = pool;
+
+	return ret;
+}
+
+void cpsw_destroy_xdp_rxqs(struct cpsw_common *cpsw)
+{
+	struct net_device *ndev;
+	int i, ch;
+
+	for (ch = 0; ch < cpsw->rx_ch_num; ch++) {
+		for (i = 0; i < cpsw->data.slaves; i++) {
+			ndev = cpsw->slaves[i].ndev;
+			if (!ndev)
+				continue;
+
+			cpsw_ndev_destroy_xdp_rxq(netdev_priv(ndev), ch);
+		}
+
+		page_pool_destroy(cpsw->page_pool[ch]);
+		cpsw->page_pool[ch] = NULL;
+	}
+}
+
+int cpsw_create_xdp_rxqs(struct cpsw_common *cpsw)
+{
+	struct net_device *ndev;
+	int i, ch, ret;
+
+	for (ch = 0; ch < cpsw->rx_ch_num; ch++) {
+		ret = cpsw_create_rx_pool(cpsw, ch);
+		if (ret)
+			goto err_cleanup;
+
+		/* using same page pool is allowed as no running rx handlers
+		 * simultaneously for both ndevs
+		 */
+		for (i = 0; i < cpsw->data.slaves; i++) {
+			ndev = cpsw->slaves[i].ndev;
+			if (!ndev)
+				continue;
+
+			ret = cpsw_ndev_create_xdp_rxq(netdev_priv(ndev), ch);
+			if (ret)
+				goto err_cleanup;
+		}
+	}
+
+	return 0;
+
+err_cleanup:
+	cpsw_destroy_xdp_rxqs(cpsw);
+
+	return ret;
+}
+
 static void cpsw_rx_handler(void *token, int len, int status)
 {
-	struct cpdma_chan	*ch;
-	struct sk_buff		*skb = token;
-	struct sk_buff		*new_skb;
-	struct net_device	*ndev = skb->dev;
-	int			ret = 0, port;
-	struct cpsw_common	*cpsw = ndev_to_cpsw(ndev);
+	struct page		*new_page, *page = token;
+	void			*pa = page_address(page);
+	struct cpsw_meta_xdp	*xmeta = pa + CPSW_XMETA_OFFSET;
+	struct cpsw_common	*cpsw = ndev_to_cpsw(xmeta->ndev);
+	int			pkt_size = cpsw->rx_packet_max;
+	int			ret = 0, port, ch = xmeta->ch;
+	int			headroom = CPSW_HEADROOM;
+	struct net_device	*ndev = xmeta->ndev;
 	struct cpsw_priv	*priv;
+	struct page_pool	*pool;
+	struct sk_buff		*skb;
+	struct xdp_buff		xdp;
+	dma_addr_t		dma;
 
-	if (cpsw->data.dual_emac) {
+	if (cpsw->data.dual_emac && status >= 0) {
 		port = CPDMA_RX_SOURCE_PORT(status);
-		if (port) {
+		if (port)
 			ndev = cpsw->slaves[--port].ndev;
-			skb->dev = ndev;
-		}
 	}
 
+	priv = netdev_priv(ndev);
+	pool = cpsw->page_pool[ch];
 	if (unlikely(status < 0) || unlikely(!netif_running(ndev))) {
 		/* In dual emac mode check for all interfaces */
 		if (cpsw->data.dual_emac && cpsw->usage_count &&
@@ -426,43 +701,87 @@ static void cpsw_rx_handler(void *token, int len, int status)
 			 * is already down and the other interface is up
 			 * and running, instead of freeing which results
 			 * in reducing of the number of rx descriptor in
-			 * DMA engine, requeue skb back to cpdma.
+			 * DMA engine, requeue page back to cpdma.
 			 */
-			new_skb = skb;
+			new_page = page;
 			goto requeue;
 		}
 
-		/* the interface is going down, skbs are purged */
-		dev_kfree_skb_any(skb);
+		/* the interface is going down, pages are purged */
+		page_pool_recycle_direct(pool, page);
 		return;
 	}
 
-	new_skb = netdev_alloc_skb_ip_align(ndev, cpsw->rx_packet_max);
-	if (new_skb) {
-		skb_copy_queue_mapping(new_skb, skb);
-		skb_put(skb, len);
-		if (status & CPDMA_RX_VLAN_ENCAP)
-			cpsw_rx_vlan_encap(skb);
-		priv = netdev_priv(ndev);
-		if (priv->rx_ts_enabled)
-			cpts_rx_timestamp(cpsw->cpts, skb);
-		skb->protocol = eth_type_trans(skb, ndev);
-		netif_receive_skb(skb);
-		ndev->stats.rx_bytes += len;
-		ndev->stats.rx_packets++;
-		kmemleak_not_leak(new_skb);
-	} else {
+	new_page = page_pool_dev_alloc_pages(pool);
+	if (unlikely(!new_page)) {
+		new_page = page;
 		ndev->stats.rx_dropped++;
-		new_skb = skb;
+		goto requeue;
+	}
+
+	if (priv->xdp_prog) {
+		if (status & CPDMA_RX_VLAN_ENCAP) {
+			xdp.data = pa + CPSW_HEADROOM +
+				   CPSW_RX_VLAN_ENCAP_HDR_SIZE;
+			xdp.data_end = xdp.data + len -
+				       CPSW_RX_VLAN_ENCAP_HDR_SIZE;
+		} else {
+			xdp.data = pa + CPSW_HEADROOM;
+			xdp.data_end = xdp.data + len;
+		}
+
+		xdp_set_data_meta_invalid(&xdp);
+
+		xdp.data_hard_start = pa;
+		xdp.rxq = &priv->xdp_rxq[ch];
+
+		ret = cpsw_run_xdp(priv, ch, &xdp, page);
+		if (ret != CPSW_XDP_PASS)
+			goto requeue;
+
+		/* XDP prog might have changed packet data and boundaries */
+		len = xdp.data_end - xdp.data;
+		headroom = xdp.data - xdp.data_hard_start;
+
+		/* XDP prog can modify vlan tag, so can't use encap header */
+		status &= ~CPDMA_RX_VLAN_ENCAP;
 	}
 
+	/* pass skb to netstack if no XDP prog or returned XDP_PASS */
+	skb = build_skb(pa, cpsw_rxbuf_total_len(pkt_size));
+	if (!skb) {
+		ndev->stats.rx_dropped++;
+		page_pool_recycle_direct(pool, page);
+		goto requeue;
+	}
+
+	skb_reserve(skb, headroom);
+	skb_put(skb, len);
+	skb->dev = ndev;
+	if (status & CPDMA_RX_VLAN_ENCAP)
+		cpsw_rx_vlan_encap(skb);
+	if (priv->rx_ts_enabled)
+		cpts_rx_timestamp(cpsw->cpts, skb);
+	skb->protocol = eth_type_trans(skb, ndev);
+
+	/* unmap page as no netstack skb page recycling */
+	page_pool_release_page(pool, page);
+	netif_receive_skb(skb);
+
+	ndev->stats.rx_bytes += len;
+	ndev->stats.rx_packets++;
+
 requeue:
-	ch = cpsw->rxv[skb_get_queue_mapping(new_skb)].ch;
-	ret = cpdma_chan_submit(ch, new_skb, new_skb->data,
-				skb_tailroom(new_skb), 0);
+	xmeta = page_address(new_page) + CPSW_XMETA_OFFSET;
+	xmeta->ndev = ndev;
+	xmeta->ch = ch;
+
+	dma = page_pool_get_dma_addr(new_page) + CPSW_HEADROOM;
+	ret = cpdma_chan_submit_mapped(cpsw->rxv[ch].ch, new_page, dma,
+				       pkt_size, 0);
 	if (ret < 0) {
 		WARN_ON(ret == -ENOMEM);
-		dev_kfree_skb_any(new_skb);
+		page_pool_recycle_direct(pool, new_page);
 	}
 }
 
@@ -1032,33 +1351,39 @@ static void cpsw_init_host_port(struct cpsw_priv *priv)
 int cpsw_fill_rx_channels(struct cpsw_priv *priv)
 {
 	struct cpsw_common *cpsw = priv->cpsw;
-	struct sk_buff *skb;
+	struct cpsw_meta_xdp *xmeta;
+	struct page_pool *pool;
+	struct page *page;
 	int ch_buf_num;
 	int ch, i, ret;
+	dma_addr_t dma;
 
 	for (ch = 0; ch < cpsw->rx_ch_num; ch++) {
+		pool = cpsw->page_pool[ch];
 		ch_buf_num = cpdma_chan_get_rx_buf_num(cpsw->rxv[ch].ch);
 		for (i = 0; i < ch_buf_num; i++) {
-			skb = __netdev_alloc_skb_ip_align(priv->ndev,
-							  cpsw->rx_packet_max,
-							  GFP_KERNEL);
-			if (!skb) {
-				cpsw_err(priv, ifup, "cannot allocate skb\n");
+			page = page_pool_dev_alloc_pages(pool);
+			if (!page) {
+				cpsw_err(priv, ifup, "allocate rx page err\n");
 				return -ENOMEM;
 			}
 
-			skb_set_queue_mapping(skb, ch);
-			ret = cpdma_chan_idle_submit(cpsw->rxv[ch].ch, skb,
-						     skb->data,
-						     skb_tailroom(skb), 0);
+			xmeta = page_address(page) + CPSW_XMETA_OFFSET;
+			xmeta->ndev = priv->ndev;
+			xmeta->ch = ch;
+
+			dma = page_pool_get_dma_addr(page) + CPSW_HEADROOM;
+			ret = cpdma_chan_idle_submit_mapped(cpsw->rxv[ch].ch,
+							    page, dma,
+							    cpsw->rx_packet_max,
+							    0);
 			if (ret < 0) {
 				cpsw_err(priv, ifup,
-					 "cannot submit skb to channel %d rx, error %d\n",
+					 "cannot submit page to channel %d rx, error %d\n",
 					 ch, ret);
-				kfree_skb(skb);
+				page_pool_recycle_direct(pool, page);
 				return ret;
 			}
-			kmemleak_not_leak(skb);
 		}
 
 		cpsw_info(priv, ifup, "ch %d rx, submitted %d descriptors\n",
@@ -1394,6 +1719,13 @@ static int cpsw_ndo_open(struct net_device *ndev)
 			enable_irq(cpsw->irqs_table[0]);
 		}
 
+		/* create rxqs for both infs in dual mac as they use same pool
+		 * and must be destroyed together when no users.
+		 */
+		ret = cpsw_create_xdp_rxqs(cpsw);
+		if (ret < 0)
+			goto err_cleanup;
+
 		ret = cpsw_fill_rx_channels(priv);
 		if (ret < 0)
 			goto err_cleanup;
@@ -1422,9 +1754,10 @@ static int cpsw_ndo_open(struct net_device *ndev)
 err_cleanup:
 	if (!cpsw->usage_count) {
 		cpdma_ctlr_stop(cpsw->dma);
-		for_each_slave(priv, cpsw_slave_stop, cpsw);
+		cpsw_destroy_xdp_rxqs(cpsw);
 	}
 
+	for_each_slave(priv, cpsw_slave_stop, cpsw);
 	pm_runtime_put_sync(cpsw->dev);
 	netif_carrier_off(priv->ndev);
 	return ret;
@@ -1447,6 +1780,7 @@ static int cpsw_ndo_stop(struct net_device *ndev)
 		cpsw_intr_disable(cpsw);
 		cpdma_ctlr_stop(cpsw->dma);
 		cpsw_ale_stop(cpsw->ale);
+		cpsw_destroy_xdp_rxqs(cpsw);
 	}
 	for_each_slave(priv, cpsw_slave_stop, cpsw);
 
@@ -2004,6 +2338,64 @@ static int cpsw_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
 	}
 }
 
+static int cpsw_xdp_prog_setup(struct cpsw_priv *priv, struct netdev_bpf *bpf)
+{
+	struct bpf_prog *prog = bpf->prog;
+
+	if (!priv->xdpi.prog && !prog)
+		return 0;
+
+	if (!xdp_attachment_flags_ok(&priv->xdpi, bpf))
+		return -EBUSY;
+
+	WRITE_ONCE(priv->xdp_prog, prog);
+
+	xdp_attachment_setup(&priv->xdpi, bpf);
+
+	return 0;
+}
+
+static int cpsw_ndo_bpf(struct net_device *ndev, struct netdev_bpf *bpf)
+{
+	struct cpsw_priv *priv = netdev_priv(ndev);
+
+	switch (bpf->command) {
+	case XDP_SETUP_PROG:
+		return cpsw_xdp_prog_setup(priv, bpf);
+
+	case XDP_QUERY_PROG:
+		return xdp_attachment_query(&priv->xdpi, bpf);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int cpsw_ndo_xdp_xmit(struct net_device *ndev, int n,
+			     struct xdp_frame **frames, u32 flags)
+{
+	struct cpsw_priv *priv = netdev_priv(ndev);
+	struct xdp_frame *xdpf;
+	int i, drops = 0;
+
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
+		return -EINVAL;
+
+	for (i = 0; i < n; i++) {
+		xdpf = frames[i];
+		if (xdpf->len < CPSW_MIN_PACKET_SIZE) {
+			xdp_return_frame_rx_napi(xdpf);
+			drops++;
+			continue;
+		}
+
+		if (cpsw_xdp_tx_frame(priv, xdpf, NULL))
+			drops++;
+	}
+
+	return n - drops;
+}
+
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void cpsw_ndo_poll_controller(struct net_device *ndev)
 {
@@ -2032,6 +2424,8 @@ static const struct net_device_ops cpsw_netdev_ops = {
 	.ndo_vlan_rx_add_vid	= cpsw_ndo_vlan_rx_add_vid,
 	.ndo_vlan_rx_kill_vid	= cpsw_ndo_vlan_rx_kill_vid,
 	.ndo_setup_tc           = cpsw_ndo_setup_tc,
+	.ndo_bpf		= cpsw_ndo_bpf,
+	.ndo_xdp_xmit		= cpsw_ndo_xdp_xmit,
 };
 
 static void cpsw_get_drvinfo(struct net_device *ndev,
diff --git a/drivers/net/ethernet/ti/cpsw_ethtool.c b/drivers/net/ethernet/ti/cpsw_ethtool.c
index e4d7185fde49..31248a6cc642 100644
--- a/drivers/net/ethernet/ti/cpsw_ethtool.c
+++ b/drivers/net/ethernet/ti/cpsw_ethtool.c
@@ -578,6 +578,18 @@ static int cpsw_update_channels_res(struct cpsw_priv *priv, int ch_num, int rx,
 	return 0;
 }
 
+static void cpsw_fail(struct cpsw_common *cpsw)
+{
+	struct net_device *ndev;
+	int i;
+
+	for (i = 0; i < cpsw->data.slaves; i++) {
+		ndev = cpsw->slaves[i].ndev;
+		if (ndev)
+			dev_close(ndev);
+	}
+}
+
 int cpsw_set_channels_common(struct net_device *ndev,
 			     struct ethtool_channels *chs,
 			     cpdma_handler_fn rx_handler)
@@ -585,7 +597,7 @@ int cpsw_set_channels_common(struct net_device *ndev,
 	struct cpsw_priv *priv = netdev_priv(ndev);
 	struct cpsw_common *cpsw = priv->cpsw;
 	struct net_device *sl_ndev;
-	int i, ret;
+	int i, new_pools, ret;
 
 	ret = cpsw_check_ch_settings(cpsw, chs);
 	if (ret < 0)
@@ -593,6 +605,8 @@ int cpsw_set_channels_common(struct net_device *ndev,
 
 	cpsw_suspend_data_pass(ndev);
 
+	new_pools = (chs->rx_count != cpsw->rx_ch_num) && cpsw->usage_count;
+
 	ret = cpsw_update_channels_res(priv, chs->rx_count, 1, rx_handler);
 	if (ret)
 		goto err;
@@ -622,12 +636,19 @@ int cpsw_set_channels_common(struct net_device *ndev,
 
 	cpsw_split_res(cpsw);
 
+	if (new_pools) {
+		cpsw_destroy_xdp_rxqs(cpsw);
+		ret = cpsw_create_xdp_rxqs(cpsw);
+		if (ret)
+			goto err;
+	}
+
 	ret = cpsw_resume_data_pass(ndev);
 	if (!ret)
 		return 0;
 err:
 	dev_err(priv->dev, "cannot update channels number, closing device\n");
-	dev_close(ndev);
+	cpsw_fail(cpsw);
 	return ret;
 }
 
@@ -647,8 +668,7 @@ void cpsw_get_ringparam(struct net_device *ndev,
 int cpsw_set_ringparam(struct net_device *ndev,
 		       struct ethtool_ringparam *ering)
 {
-	struct cpsw_priv *priv = netdev_priv(ndev);
-	struct cpsw_common *cpsw = priv->cpsw;
+	struct cpsw_common *cpsw = ndev_to_cpsw(ndev);
 	int descs_num, ret;
 
 	/* ignore ering->tx_pending - only rx_pending adjustment is supported */
@@ -672,13 +692,20 @@ int cpsw_set_ringparam(struct net_device *ndev,
 		return ret;
 	}
 
+	if (cpsw->usage_count) {
+		cpsw_destroy_xdp_rxqs(cpsw);
+		ret = cpsw_create_xdp_rxqs(cpsw);
+		if (ret)
+			goto err;
+	}
+
 	ret = cpsw_resume_data_pass(ndev);
 	if (!ret)
 		return 0;
 err:
 	cpdma_set_num_rx_descs(cpsw->dma, descs_num);
 	dev_err(cpsw->dev, "cannot set ring params, closing device\n");
-	dev_close(ndev);
+	cpsw_fail(cpsw);
 	return ret;
 }
 
diff --git a/drivers/net/ethernet/ti/cpsw_priv.h b/drivers/net/ethernet/ti/cpsw_priv.h
index 04795b97ee71..086bf38a4736 100644
--- a/drivers/net/ethernet/ti/cpsw_priv.h
+++ b/drivers/net/ethernet/ti/cpsw_priv.h
@@ -346,6 +346,7 @@ struct cpsw_common {
 	int				rx_ch_num, tx_ch_num;
 	int				speed;
 	int				usage_count;
+	struct page_pool		*page_pool[CPSW_MAX_QUEUES];
 };
 
 struct cpsw_priv {
@@ -360,6 +361,10 @@ struct cpsw_priv {
 	int				shp_cfg_speed;
 	int				tx_ts_enabled;
 	int				rx_ts_enabled;
+	struct bpf_prog			*xdp_prog;
+	struct xdp_rxq_info		xdp_rxq[CPSW_MAX_QUEUES];
+	struct xdp_attachment_info	xdpi;
+
 	u32 emac_port;
 	struct cpsw_common *cpsw;
 };
@@ -391,6 +396,8 @@ int cpsw_fill_rx_channels(struct cpsw_priv *priv);
 void cpsw_intr_enable(struct cpsw_common *cpsw);
 void cpsw_intr_disable(struct cpsw_common *cpsw);
 void cpsw_tx_handler(void *token, int len, int status);
+int cpsw_create_xdp_rxqs(struct cpsw_common *cpsw);
+void cpsw_destroy_xdp_rxqs(struct cpsw_common *cpsw);
 
 /* ethtool */
 u32 cpsw_get_msglevel(struct net_device *ndev);
-- 
2.17.1

Re: [PATCH v7 net-next 1/5] net: core: page_pool: add user refcnt and reintroduce page_pool_destroy

[Jesper Dangaard Brouer]

CC: Tariq + Saeed, could you please review the mlx5 part.

On Fri,  5 Jul 2019 02:14:02 +0300
Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:

> Jesper recently removed page_pool_destroy() (from driver invocation)
> and moved shutdown and free of page_pool into xdp_rxq_info_unreg(),
> in-order to handle in-flight packets/pages. This created an asymmetry
> in drivers create/destroy pairs.
> 
> This patch reintroduce page_pool_destroy and add page_pool user
> refcnt. This serves the purpose to simplify drivers error handling as
> driver now drivers always calls page_pool_destroy() and don't need to
> track if xdp_rxq_info_reg_mem_model() was unsuccessful.
> 
> This could be used for a special cases where a single RX-queue (with a
> single page_pool) provides packets for two net_device'es, and thus
> needs to register the same page_pool twice with two xdp_rxq_info
> structures.
> 
> This patch is primarily to ease API usage for drivers. The recently
> merged netsec driver, actually have a bug in this area, which is
> solved by this API change.
> 
> This patch is a modified version of Ivan Khoronzhu's original patch.
> 
> Link: https://lore.kernel.org/netdev/20190625175948.24771-2-ivan.khoronzhuk@linaro.org/
> Fixes: 5c67bf0ec4d0 ("net: netsec: Use page_pool API")
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>

Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>

Thank you Ivan for taking this more simple approach.  If we later see
more drivers wanting this feature of a single RX-queue providing
packets to multiple net_device'es, then we can change into your
more generic API at XDP-reg-layer approach later.  For now, we keep
code complexity as low as possible.


> ---
>  .../net/ethernet/mellanox/mlx5/core/en_main.c |  4 +--
>  drivers/net/ethernet/socionext/netsec.c       |  8 ++----
>  include/net/page_pool.h                       | 25 +++++++++++++++++++
>  net/core/page_pool.c                          |  8 ++++++
>  net/core/xdp.c                                |  3 +++
>  5 files changed, 40 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> index 2f9093ba82aa..ac882b2341d0 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> @@ -575,8 +575,6 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
>  		}
>  		err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
>  						 MEM_TYPE_PAGE_POOL, rq->page_pool);
> -		if (err)
> -			page_pool_free(rq->page_pool);
>  	}
>  	if (err)
>  		goto err_free;
> @@ -644,6 +642,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
>  	if (rq->xdp_prog)
>  		bpf_prog_put(rq->xdp_prog);
>  	xdp_rxq_info_unreg(&rq->xdp_rxq);
> +	page_pool_destroy(rq->page_pool);
>  	mlx5_wq_destroy(&rq->wq_ctrl);
>  
>  	return err;
> @@ -678,6 +677,7 @@ static void mlx5e_free_rq(struct mlx5e_rq *rq)
>  	}
>  
>  	xdp_rxq_info_unreg(&rq->xdp_rxq);
> +	page_pool_destroy(rq->page_pool);
>  	mlx5_wq_destroy(&rq->wq_ctrl);
>  }
>  
> diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
> index 5544a722543f..43ab0ce90704 100644
> --- a/drivers/net/ethernet/socionext/netsec.c
> +++ b/drivers/net/ethernet/socionext/netsec.c
> @@ -1210,15 +1210,11 @@ static void netsec_uninit_pkt_dring(struct netsec_priv *priv, int id)
>  		}
>  	}
>  
> -	/* Rx is currently using page_pool
> -	 * since the pool is created during netsec_setup_rx_dring(), we need to
> -	 * free the pool manually if the registration failed
> -	 */
> +	/* Rx is currently using page_pool */
>  	if (id == NETSEC_RING_RX) {
>  		if (xdp_rxq_info_is_reg(&dring->xdp_rxq))
>  			xdp_rxq_info_unreg(&dring->xdp_rxq);
> -		else
> -			page_pool_free(dring->page_pool);
> +		page_pool_destroy(dring->page_pool);
>  	}
>  
>  	memset(dring->desc, 0, sizeof(struct netsec_desc) * DESC_NUM);
> diff --git a/include/net/page_pool.h b/include/net/page_pool.h
> index ee9c871d2043..2cbcdbdec254 100644
> --- a/include/net/page_pool.h
> +++ b/include/net/page_pool.h
> @@ -101,6 +101,12 @@ struct page_pool {
>  	struct ptr_ring ring;
>  
>  	atomic_t pages_state_release_cnt;
> +
> +	/* A page_pool is strictly tied to a single RX-queue being
> +	 * protected by NAPI, due to above pp_alloc_cache. This
> +	 * refcnt serves purpose is to simplify drivers error handling.
> +	 */
> +	refcount_t user_cnt;
>  };
>  
>  struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
> @@ -134,6 +140,15 @@ static inline void page_pool_free(struct page_pool *pool)
>  #endif
>  }
>  
> +/* Drivers use this instead of page_pool_free */
> +static inline void page_pool_destroy(struct page_pool *pool)
> +{
> +	if (!pool)
> +		return;
> +
> +	page_pool_free(pool);
> +}
> +
>  /* Never call this directly, use helpers below */
>  void __page_pool_put_page(struct page_pool *pool,
>  			  struct page *page, bool allow_direct);
> @@ -201,4 +216,14 @@ static inline bool is_page_pool_compiled_in(void)
>  #endif
>  }
>  
> +static inline void page_pool_get(struct page_pool *pool)
> +{
> +	refcount_inc(&pool->user_cnt);
> +}
> +
> +static inline bool page_pool_put(struct page_pool *pool)
> +{
> +	return refcount_dec_and_test(&pool->user_cnt);
> +}
> +
>  #endif /* _NET_PAGE_POOL_H */
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index b366f59885c1..3272dc7a8c81 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -49,6 +49,9 @@ static int page_pool_init(struct page_pool *pool,
>  
>  	atomic_set(&pool->pages_state_release_cnt, 0);
>  
> +	/* Driver calling page_pool_create() also call page_pool_destroy() */
> +	refcount_set(&pool->user_cnt, 1);
> +
>  	if (pool->p.flags & PP_FLAG_DMA_MAP)
>  		get_device(pool->p.dev);
>  
> @@ -70,6 +73,7 @@ struct page_pool *page_pool_create(const struct page_pool_params *params)
>  		kfree(pool);
>  		return ERR_PTR(err);
>  	}
> +
>  	return pool;
>  }
>  EXPORT_SYMBOL(page_pool_create);
> @@ -356,6 +360,10 @@ static void __warn_in_flight(struct page_pool *pool)
>  
>  void __page_pool_free(struct page_pool *pool)
>  {
> +	/* Only last user actually free/release resources */
> +	if (!page_pool_put(pool))
> +		return;
> +
>  	WARN(pool->alloc.count, "API usage violation");
>  	WARN(!ptr_ring_empty(&pool->ring), "ptr_ring is not empty");
>  
> diff --git a/net/core/xdp.c b/net/core/xdp.c
> index 829377cc83db..d7bf62ffbb5e 100644
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c
> @@ -370,6 +370,9 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
>  		goto err;
>  	}
>  
> +	if (type == MEM_TYPE_PAGE_POOL)
> +		page_pool_get(xdp_alloc->page_pool);
> +
>  	mutex_unlock(&mem_id_lock);
>  
>  	trace_mem_connect(xdp_alloc, xdp_rxq);



-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

Re: [PATCH v7 net-next 5/5] net: ethernet: ti: cpsw: add XDP support

[Jesper Dangaard Brouer]

On Fri,  5 Jul 2019 02:14:06 +0300
Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:

> Add XDP support based on rx page_pool allocator, one frame per page.
> Page pool allocator is used with assumption that only one rx_handler
> is running simultaneously. DMA map/unmap is reused from page pool
> despite there is no need to map whole page.
> 
> Due to specific of cpsw, the same TX/RX handler can be used by 2
> network devices, so special fields in buffer are added to identify
> an interface the frame is destined to. Thus XDP works for both
> interfaces, that allows to test xdp redirect between two interfaces
> easily. Aslo, each rx queue have own page pools, but common for both
          ^^^^
          Also

> netdevs.
> 
> XDP prog is common for all channels till appropriate changes are added
> in XDP infrastructure. Also, once page_pool recycling becomes part of
> skb netstack some simplifications can be added, like removing
> page_pool_release_page() before skb receive.
> 
> In order to keep rx_dev while redirect, that can be somehow used in
> future, do flush in rx_handler, that allows to keep rx dev the same
> while reidrect. It allows to conform with tracing rx_dev pointed
        ^^^^^^^^
        redirect

> by Jesper.
> 
> Also, there is probability, that XDP generic code can be extended to
> support multi ndev drivers like this one, using same rx queue for
> several ndevs, based on switchdev for instance or else. In this case,
> driver can be modified like exposed here:
> https://lkml.org/lkml/2019/7/3/243
> 
> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>

Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>

I didn't spot any issues, but I don't have access to this hardware, so
I've not tested it.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

Re: [PATCH v7 net-next 5/5] net: ethernet: ti: cpsw: add XDP support

[Jesper Dangaard Brouer]

On Fri,  5 Jul 2019 02:14:06 +0300
Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:

> +static int cpsw_xdp_tx_frame(struct cpsw_priv *priv, struct xdp_frame *xdpf,
> +			     struct page *page)
> +{
> +	struct cpsw_common *cpsw = priv->cpsw;
> +	struct cpsw_meta_xdp *xmeta;
> +	struct cpdma_chan *txch;
> +	dma_addr_t dma;
> +	int ret, port;
> +
> +	xmeta = (void *)xdpf + CPSW_XMETA_OFFSET;
> +	xmeta->ndev = priv->ndev;
> +	xmeta->ch = 0;
> +	txch = cpsw->txv[0].ch;
> +
> +	port = priv->emac_port + cpsw->data.dual_emac;
> +	if (page) {
> +		dma = page_pool_get_dma_addr(page);
> +		dma += xdpf->data - (void *)xdpf;

This code is only okay because this only happens for XDP_TX, where you
know this head-room calculation will be true.  The "correct"
calculation of the head-room would be:

  dma += xdpf->headroom + sizeof(struct xdp_frame);

The reason behind not using xdpf pointer itself as "data_hard_start",
is to allow struct xdp_frame to be located in another memory area.
This will be useful for e.g. AF_XDP transmit, or other zero-copy
transmit to go through ndo_xdp_xmit() (as we don't want userspace to
be-able to e.g. "race" change xdpf->len during transmit/DMA-completion).


> +		ret = cpdma_chan_submit_mapped(txch, cpsw_xdpf_to_handle(xdpf),
> +					       dma, xdpf->len, port);
> +	} else {
> +		if (sizeof(*xmeta) > xdpf->headroom) {
> +			xdp_return_frame_rx_napi(xdpf);
> +			return -EINVAL;
> +		}
> +
> +		ret = cpdma_chan_submit(txch, cpsw_xdpf_to_handle(xdpf),
> +					xdpf->data, xdpf->len, port);
> +	}



-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

Re: [PATCH v7 net-next 5/5] net: ethernet: ti: cpsw: add XDP support

[Ivan Khoronzhuk]

On Fri, Jul 05, 2019 at 01:13:54PM +0200, Jesper Dangaard Brouer wrote:
>On Fri,  5 Jul 2019 02:14:06 +0300
>Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:
>
>> +static int cpsw_xdp_tx_frame(struct cpsw_priv *priv, struct xdp_frame *xdpf,
>> +			     struct page *page)
>> +{
>> +	struct cpsw_common *cpsw = priv->cpsw;
>> +	struct cpsw_meta_xdp *xmeta;
>> +	struct cpdma_chan *txch;
>> +	dma_addr_t dma;
>> +	int ret, port;
>> +
>> +	xmeta = (void *)xdpf + CPSW_XMETA_OFFSET;
>> +	xmeta->ndev = priv->ndev;
>> +	xmeta->ch = 0;
>> +	txch = cpsw->txv[0].ch;
>> +
>> +	port = priv->emac_port + cpsw->data.dual_emac;
>> +	if (page) {
>> +		dma = page_pool_get_dma_addr(page);
>> +		dma += xdpf->data - (void *)xdpf;
>
>This code is only okay because this only happens for XDP_TX, where you
>know this head-room calculation will be true.  The "correct"
>calculation of the head-room would be:
>
>  dma += xdpf->headroom + sizeof(struct xdp_frame);
>
>The reason behind not using xdpf pointer itself as "data_hard_start",
>is to allow struct xdp_frame to be located in another memory area.

My assumption was based on:

struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
{
	...
	xdp_frame = xdp->data_hard_start;
	...

	xdp_frame->headroom = headroom - sizeof(*xdp_frame);
	...
}

But agree, it doesn't contradict the reason in question.
So, better use proposed variant. Will check and do this in v8 a little later:

dma += xdpf->headroom + sizeof(struct xdp_frame);

>This will be useful for e.g. AF_XDP transmit, or other zero-copy
>transmit to go through ndo_xdp_xmit() (as we don't want userspace to
>be-able to e.g. "race" change xdpf->len during transmit/DMA-completion).
>
>
>> +		ret = cpdma_chan_submit_mapped(txch, cpsw_xdpf_to_handle(xdpf),
>> +					       dma, xdpf->len, port);
>> +	} else {
>> +		if (sizeof(*xmeta) > xdpf->headroom) {
>> +			xdp_return_frame_rx_napi(xdpf);
>> +			return -EINVAL;
>> +		}
>> +
>> +		ret = cpdma_chan_submit(txch, cpsw_xdpf_to_handle(xdpf),
>> +					xdpf->data, xdpf->len, port);
>> +	}
>
>
>
>-- 
>Best regards,
>  Jesper Dangaard Brouer
>  MSc.CS, Principal Kernel Engineer at Red Hat
>  LinkedIn: http://www.linkedin.com/in/brouer

-- 
Regards,
Ivan Khoronzhuk

Re: [PATCH v7 net-next 1/5] net: core: page_pool: add user refcnt and reintroduce page_pool_destroy

[Saeed Mahameed]

On Fri, Jul 5, 2019 at 3:45 AM Jesper Dangaard Brouer <brouer@redhat.com> wrote:
>
>
> CC: Tariq + Saeed, could you please review the mlx5 part.
>
> On Fri,  5 Jul 2019 02:14:02 +0300
> Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:
>
> > Jesper recently removed page_pool_destroy() (from driver invocation)
> > and moved shutdown and free of page_pool into xdp_rxq_info_unreg(),
> > in-order to handle in-flight packets/pages. This created an asymmetry
> > in drivers create/destroy pairs.
> >
> > This patch reintroduce page_pool_destroy and add page_pool user
> > refcnt. This serves the purpose to simplify drivers error handling as
> > driver now drivers always calls page_pool_destroy() and don't need to
> > track if xdp_rxq_info_reg_mem_model() was unsuccessful.
> >
> > This could be used for a special cases where a single RX-queue (with a
> > single page_pool) provides packets for two net_device'es, and thus
> > needs to register the same page_pool twice with two xdp_rxq_info
> > structures.
> >
> > This patch is primarily to ease API usage for drivers. The recently
> > merged netsec driver, actually have a bug in this area, which is
> > solved by this API change.
> >

This patch and the mlx5 part looks good to me,
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>

> > This patch is a modified version of Ivan Khoronzhu's original patch.
> >
> > Link: https://lore.kernel.org/netdev/20190625175948.24771-2-ivan.khoronzhuk@linaro.org/
> > Fixes: 5c67bf0ec4d0 ("net: netsec: Use page_pool API")
> > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> > Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
>
> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
>
> Thank you Ivan for taking this more simple approach.  If we later see
> more drivers wanting this feature of a single RX-queue providing
> packets to multiple net_device'es, then we can change into your
> more generic API at XDP-reg-layer approach later.  For now, we keep
> code complexity as low as possible.
>
>
> > ---
> >  .../net/ethernet/mellanox/mlx5/core/en_main.c |  4 +--
> >  drivers/net/ethernet/socionext/netsec.c       |  8 ++----
> >  include/net/page_pool.h                       | 25 +++++++++++++++++++
> >  net/core/page_pool.c                          |  8 ++++++
> >  net/core/xdp.c                                |  3 +++
> >  5 files changed, 40 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > index 2f9093ba82aa..ac882b2341d0 100644
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > @@ -575,8 +575,6 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
> >               }
> >               err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
> >                                                MEM_TYPE_PAGE_POOL, rq->page_pool);
> > -             if (err)
> > -                     page_pool_free(rq->page_pool);
> >       }
> >       if (err)
> >               goto err_free;
> > @@ -644,6 +642,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
> >       if (rq->xdp_prog)
> >               bpf_prog_put(rq->xdp_prog);
> >       xdp_rxq_info_unreg(&rq->xdp_rxq);
> > +     page_pool_destroy(rq->page_pool);
> >       mlx5_wq_destroy(&rq->wq_ctrl);
> >
> >       return err;
> > @@ -678,6 +677,7 @@ static void mlx5e_free_rq(struct mlx5e_rq *rq)
> >       }
> >
> >       xdp_rxq_info_unreg(&rq->xdp_rxq);
> > +     page_pool_destroy(rq->page_pool);
> >       mlx5_wq_destroy(&rq->wq_ctrl);
> >  }
> >
> > diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
> > index 5544a722543f..43ab0ce90704 100644
> > --- a/drivers/net/ethernet/socionext/netsec.c
> > +++ b/drivers/net/ethernet/socionext/netsec.c
> > @@ -1210,15 +1210,11 @@ static void netsec_uninit_pkt_dring(struct netsec_priv *priv, int id)
> >               }
> >       }
> >
> > -     /* Rx is currently using page_pool
> > -      * since the pool is created during netsec_setup_rx_dring(), we need to
> > -      * free the pool manually if the registration failed
> > -      */
> > +     /* Rx is currently using page_pool */
> >       if (id == NETSEC_RING_RX) {
> >               if (xdp_rxq_info_is_reg(&dring->xdp_rxq))
> >                       xdp_rxq_info_unreg(&dring->xdp_rxq);
> > -             else
> > -                     page_pool_free(dring->page_pool);
> > +             page_pool_destroy(dring->page_pool);
> >       }
> >
> >       memset(dring->desc, 0, sizeof(struct netsec_desc) * DESC_NUM);
> > diff --git a/include/net/page_pool.h b/include/net/page_pool.h
> > index ee9c871d2043..2cbcdbdec254 100644
> > --- a/include/net/page_pool.h
> > +++ b/include/net/page_pool.h
> > @@ -101,6 +101,12 @@ struct page_pool {
> >       struct ptr_ring ring;
> >
> >       atomic_t pages_state_release_cnt;
> > +
> > +     /* A page_pool is strictly tied to a single RX-queue being
> > +      * protected by NAPI, due to above pp_alloc_cache. This
> > +      * refcnt serves purpose is to simplify drivers error handling.
> > +      */
> > +     refcount_t user_cnt;
> >  };
> >
> >  struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
> > @@ -134,6 +140,15 @@ static inline void page_pool_free(struct page_pool *pool)
> >  #endif
> >  }
> >
> > +/* Drivers use this instead of page_pool_free */
> > +static inline void page_pool_destroy(struct page_pool *pool)
> > +{
> > +     if (!pool)
> > +             return;
> > +
> > +     page_pool_free(pool);
> > +}
> > +
> >  /* Never call this directly, use helpers below */
> >  void __page_pool_put_page(struct page_pool *pool,
> >                         struct page *page, bool allow_direct);
> > @@ -201,4 +216,14 @@ static inline bool is_page_pool_compiled_in(void)
> >  #endif
> >  }
> >
> > +static inline void page_pool_get(struct page_pool *pool)
> > +{
> > +     refcount_inc(&pool->user_cnt);
> > +}
> > +
> > +static inline bool page_pool_put(struct page_pool *pool)
> > +{
> > +     return refcount_dec_and_test(&pool->user_cnt);
> > +}
> > +
> >  #endif /* _NET_PAGE_POOL_H */
> > diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> > index b366f59885c1..3272dc7a8c81 100644
> > --- a/net/core/page_pool.c
> > +++ b/net/core/page_pool.c
> > @@ -49,6 +49,9 @@ static int page_pool_init(struct page_pool *pool,
> >
> >       atomic_set(&pool->pages_state_release_cnt, 0);
> >
> > +     /* Driver calling page_pool_create() also call page_pool_destroy() */
> > +     refcount_set(&pool->user_cnt, 1);
> > +
> >       if (pool->p.flags & PP_FLAG_DMA_MAP)
> >               get_device(pool->p.dev);
> >
> > @@ -70,6 +73,7 @@ struct page_pool *page_pool_create(const struct page_pool_params *params)
> >               kfree(pool);
> >               return ERR_PTR(err);
> >       }
> > +
> >       return pool;
> >  }
> >  EXPORT_SYMBOL(page_pool_create);
> > @@ -356,6 +360,10 @@ static void __warn_in_flight(struct page_pool *pool)
> >
> >  void __page_pool_free(struct page_pool *pool)
> >  {
> > +     /* Only last user actually free/release resources */
> > +     if (!page_pool_put(pool))
> > +             return;
> > +
> >       WARN(pool->alloc.count, "API usage violation");
> >       WARN(!ptr_ring_empty(&pool->ring), "ptr_ring is not empty");
> >
> > diff --git a/net/core/xdp.c b/net/core/xdp.c
> > index 829377cc83db..d7bf62ffbb5e 100644
> > --- a/net/core/xdp.c
> > +++ b/net/core/xdp.c
> > @@ -370,6 +370,9 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
> >               goto err;
> >       }
> >
> > +     if (type == MEM_TYPE_PAGE_POOL)
> > +             page_pool_get(xdp_alloc->page_pool);
> > +
> >       mutex_unlock(&mem_id_lock);
> >
> >       trace_mem_connect(xdp_alloc, xdp_rxq);
>
>
>
> --
> Best regards,
>   Jesper Dangaard Brouer
>   MSc.CS, Principal Kernel Engineer at Red Hat
>   LinkedIn: http://www.linkedin.com/in/brouer