diff mbox series

[net-next,v9,8/9] net: check for driver support in netmem TX

Message ID 20250417231540.2780723-9-almasrymina@google.com (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series Device memory TCP TX | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; GEN HAS DIFF 2 files changed, 115 insertions(+);
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 2 maintainers not CCed: jdamato@fastly.com kaiyuanz@google.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 7 this patch: 7
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 69 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 69 this patch: 69
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2025-04-18--09-00 (tests: 916)

Commit Message

Mina Almasry April 17, 2025, 11:15 p.m. UTC 
We should not enable netmem TX for drivers that don't declare support.

Check for driver netmem TX support during devmem TX binding and fail if
the driver does not have the functionality.

Check for driver support in validate_xmit_skb as well.

Signed-off-by: Mina Almasry <almasrymina@google.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>

---

v8:
- Rebase on latest net-next and resolve conflict.
- Remove likely (Paolo)

v5: https://lore.kernel.org/netdev/20250227041209.2031104-8-almasrymina@google.com/
- Check that the dmabuf mappings belongs to the specific device the TX
  is being sent from (Jakub)

v4:
- New patch

---
 net/core/dev.c         | 34 ++++++++++++++++++++++++++++++++--
 net/core/devmem.h      |  6 ++++++
 net/core/netdev-genl.c |  7 +++++++
 3 files changed, 45 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/core/dev.c b/net/core/dev.c
index d1a8cad0c99c..66f0c122de80 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3896,12 +3896,42 @@  int skb_csum_hwoffload_help(struct sk_buff *skb,
 }
 EXPORT_SYMBOL(skb_csum_hwoffload_help);
 
+static struct sk_buff *validate_xmit_unreadable_skb(struct sk_buff *skb,
+						    struct net_device *dev)
+{
+	struct skb_shared_info *shinfo;
+	struct net_iov *niov;
+
+	if (likely(skb_frags_readable(skb)))
+		goto out;
+
+	if (!dev->netmem_tx)
+		goto out_free;
+
+	shinfo = skb_shinfo(skb);
+
+	if (shinfo->nr_frags > 0) {
+		niov = netmem_to_net_iov(skb_frag_netmem(&shinfo->frags[0]));
+		if (net_is_devmem_iov(niov) &&
+		    net_devmem_iov_binding(niov)->dev != dev)
+			goto out_free;
+	}
+
+out:
+	return skb;
+
+out_free:
+	kfree_skb(skb);
+	return NULL;
+}
+
 static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device *dev, bool *again)
 {
 	netdev_features_t features;
 
-	if (!skb_frags_readable(skb))
-		goto out_kfree_skb;
+	skb = validate_xmit_unreadable_skb(skb, dev);
+	if (unlikely(!skb))
+		goto out_null;
 
 	features = netif_skb_features(skb);
 	skb = validate_xmit_vlan(skb, features);
diff --git a/net/core/devmem.h b/net/core/devmem.h
index 67168aae5e5b..919e6ed28fdc 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -229,6 +229,12 @@  net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr,
 {
 	return NULL;
 }
+
+static inline struct net_devmem_dmabuf_binding *
+net_devmem_iov_binding(const struct net_iov *niov)
+{
+	return NULL;
+}
 #endif
 
 #endif /* _NET_DEVMEM_H */
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 5f44f7a3cbdb..b221fbbc5eca 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -974,6 +974,13 @@  int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
 		goto err_unlock_sock;
 	}
 
+	if (!netdev->netmem_tx) {
+		err = -EOPNOTSUPP;
+		NL_SET_ERR_MSG(info->extack,
+			       "Driver does not support netmem TX");
+		goto err_unlock_netdev;
+	}
+
 	binding = net_devmem_bind_dmabuf(netdev, DMA_TO_DEVICE, dmabuf_fd,
 					 info->extack);
 	if (IS_ERR(binding)) {