diff mbox series

[net-next,v2,2/3] net: introduce abstraction for network memory

Message ID 20231217080913.2025973-3-almasrymina@google.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Abstract page from net stack | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
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: 1115 this patch: 1115
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/build_clang success Errors and warnings before: 1142 this patch: 1142
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: 1142 this patch: 1142
netdev/checkpatch warning WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Mina Almasry Dec. 17, 2023, 8:09 a.m. UTC 
Add the netmem_t type, an abstraction for network memory.

To add support for new memory types to the net stack, we must first
abstract the current memory type from the net stack. Currently parts of
the net stack use struct page directly:

- page_pool
- drivers
- skb_frag_t

Originally the plan was to reuse struct page* for the new memory types,
and to set the LSB on the page* to indicate it's not really a page.
However, for compiler type checking we need to introduce a new type.

netmem_t is introduced to abstract the underlying memory type. Currently
it's a no-op abstraction that is always a struct page underneath. In
parallel there is an undergoing effort to add support for devmem to the
net stack:

https://lore.kernel.org/netdev/20231208005250.2910004-1-almasrymina@google.com/

Signed-off-by: Mina Almasry <almasrymina@google.com>

---

v2:

- Use container_of instead of a type cast (David).
---
 include/net/netmem.h | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 include/net/netmem.h
diff mbox series

Patch

diff --git a/include/net/netmem.h b/include/net/netmem.h
new file mode 100644
index 000000000000..b60b00216704
--- /dev/null
+++ b/include/net/netmem.h
@@ -0,0 +1,35 @@ 
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * netmem.h
+ *	Author:	Mina Almasry <almasrymina@google.com>
+ *	Copyright (C) 2023 Google LLC
+ */
+
+#ifndef _NET_NETMEM_H
+#define _NET_NETMEM_H
+
+struct netmem {
+	union {
+		struct page page;
+
+		/* Stub to prevent compiler implicitly converting from page*
+		 * to netmem_t* and vice versa.
+		 *
+		 * Other memory type(s) net stack would like to support
+		 * can be added to this union.
+		 */
+		void *addr;
+	};
+};
+
+static inline struct page *netmem_to_page(struct netmem *netmem)
+{
+	return &netmem->page;
+}
+
+static inline struct netmem *page_to_netmem(struct page *page)
+{
+	return container_of(page, struct netmem, page);
+}
+
+#endif /* _NET_NETMEM_H */