[PATCH v7 04/15] net: prepare for non devmem TCP memory providers

[David Wei <dw@davidwei.uk>]

From: Pavel Begunkov <asml.silence@gmail.com>

There is a good bunch of places in generic paths assuming that the only
page pool memory provider is devmem TCP. As we want to reuse the net_iov
and provider infrastructure, we need to patch it up and explicitly check
the provider type when we branch into devmem TCP code.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David Wei <dw@davidwei.uk>
---
 net/core/devmem.c         | 10 ++++++++--
 net/core/devmem.h         |  8 ++++++++
 net/core/page_pool_user.c | 15 +++++++++------
 net/ipv4/tcp.c            |  6 ++++++
 4 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/net/core/devmem.c b/net/core/devmem.c
index 01738029e35c..78983a98e5dc 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -28,6 +28,12 @@ static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1);
 
 static const struct memory_provider_ops dmabuf_devmem_ops;
 
+bool net_is_devmem_page_pool_ops(const struct memory_provider_ops *ops)
+{
+	return ops == &dmabuf_devmem_ops;
+}
+EXPORT_SYMBOL_GPL(net_is_devmem_page_pool_ops);
+
 static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool,
 					       struct gen_pool_chunk *chunk,
 					       void *not_used)
@@ -316,10 +322,10 @@ void dev_dmabuf_uninstall(struct net_device *dev)
 	unsigned int i;
 
 	for (i = 0; i < dev->real_num_rx_queues; i++) {
-		binding = dev->_rx[i].mp_params.mp_priv;
-		if (!binding)
+		if (dev->_rx[i].mp_params.mp_ops != &dmabuf_devmem_ops)
 			continue;
 
+		binding = dev->_rx[i].mp_params.mp_priv;
 		xa_for_each(&binding->bound_rxqs, xa_idx, rxq)
 			if (rxq == &dev->_rx[i]) {
 				xa_erase(&binding->bound_rxqs, xa_idx);
diff --git a/net/core/devmem.h b/net/core/devmem.h
index a2b9913e9a17..a3fdd66bb05b 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -116,6 +116,8 @@ struct net_iov *
 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding);
 void net_devmem_free_dmabuf(struct net_iov *ppiov);
 
+bool net_is_devmem_page_pool_ops(const struct memory_provider_ops *ops);
+
 #else
 struct net_devmem_dmabuf_binding;
 
@@ -168,6 +170,12 @@ static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov)
 {
 	return 0;
 }
+
+static inline bool
+net_is_devmem_page_pool_ops(const struct memory_provider_ops *ops)
+{
+	return false;
+}
 #endif
 
 #endif /* _NET_DEVMEM_H */
diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
index 48335766c1bf..604862a73535 100644
--- a/net/core/page_pool_user.c
+++ b/net/core/page_pool_user.c
@@ -214,7 +214,7 @@ static int
 page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
 		  const struct genl_info *info)
 {
-	struct net_devmem_dmabuf_binding *binding = pool->mp_priv;
+	struct net_devmem_dmabuf_binding *binding;
 	size_t inflight, refsz;
 	void *hdr;
 
@@ -244,8 +244,11 @@ page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
 			 pool->user.detach_time))
 		goto err_cancel;
 
-	if (binding && nla_put_u32(rsp, NETDEV_A_PAGE_POOL_DMABUF, binding->id))
-		goto err_cancel;
+	if (net_is_devmem_page_pool_ops(pool->mp_ops)) {
+		binding = pool->mp_priv;
+		if (nla_put_u32(rsp, NETDEV_A_PAGE_POOL_DMABUF, binding->id))
+			goto err_cancel;
+	}
 
 	genlmsg_end(rsp, hdr);
 
@@ -353,16 +356,16 @@ void page_pool_unlist(struct page_pool *pool)
 int page_pool_check_memory_provider(struct net_device *dev,
 				    struct netdev_rx_queue *rxq)
 {
-	struct net_devmem_dmabuf_binding *binding = rxq->mp_params.mp_priv;
+	void *mp_priv = rxq->mp_params.mp_priv;
 	struct page_pool *pool;
 	struct hlist_node *n;
 
-	if (!binding)
+	if (!mp_priv)
 		return 0;
 
 	mutex_lock(&page_pools_lock);
 	hlist_for_each_entry_safe(pool, n, &dev->page_pools, user.list) {
-		if (pool->mp_priv != binding)
+		if (pool->mp_priv != mp_priv)
 			continue;
 
 		if (pool->slow.queue_idx == get_netdev_rx_queue_index(rxq)) {
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index e928efc22f80..31e01da61c12 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -277,6 +277,7 @@
 #include <net/ip.h>
 #include <net/sock.h>
 #include <net/rstreason.h>
+#include <net/page_pool/types.h>
 
 #include <linux/uaccess.h>
 #include <asm/ioctls.h>
@@ -2476,6 +2477,11 @@ static int tcp_recvmsg_dmabuf(struct sock *sk, const struct sk_buff *skb,
 			}
 
 			niov = skb_frag_net_iov(frag);
+			if (net_is_devmem_page_pool_ops(niov->pp->mp_ops)) {
+				err = -ENODEV;
+				goto out;
+			}
+
 			end = start + skb_frag_size(frag);
 			copy = end - offset;
 
-- 
2.43.5