On Sat, 31 Aug 2024 00:43:11 +0000 Mina Almasry wrote:

+The socket must be flow steered to the dmabuf bound RX queue::
+
+	ethtool -N eth1 flow-type tcp4 ... queue 15,

nit: tailing comma here

+Devmem payloads are inaccessible to the kernel processing the packets. This
+results in a few quirks for payloads of devmem skbs:
+
+- Loopback is not functional. Loopback relies on copying the payload, which is
+  not possible with devmem skbs.
+
+- Software checksum calculation fails.

Speaking of which, I think we need to add readability check to 
skb_checksum_help(). Shouldn't the check in __skb_checksum() 
have a WARN_ON_ONCE() around it? It's impossible to return 
an error from there.

+- TCP Dump and bpf can't access devmem packet payloads.
+
+
+Testing
+=======
+
+More realistic example code can be found in the kernel source under
+tools/testing/selftests/net/ncdevmem.c

looks like HTML output wraps the file path, maybe quote it as
``tools/testing/selftests/net/ncdevmem.c`` ?