From 78476d315e190533757ab894255c4f2c2f254bce Mon Sep 17 00:00:00 2001
From: Jeremy Kerr <jk@codeconstruct.com.au>
Date: Fri, 29 Oct 2021 11:01:44 +0800
Subject: [PATCH] mctp: Add flow extension to skb
This change adds a new skb extension for MCTP, to represent a
request/response flow.
The intention is to use this in a later change to allow i2c controllers
to correctly configure a multiplexer over a flow.
Since we have a cleanup function in the core path (if an extension is
present), we'll need to make CONFIG_MCTP a bool, rather than a tristate.
Includes a fix for a build warning with clang:
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/linux/skbuff.h | 3 +++
include/net/mctp.h | 7 +++++++
net/core/skbuff.c | 19 +++++++++++++++++++
net/mctp/Kconfig | 7 ++++++-
4 files changed, 35 insertions(+), 1 deletion(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index cb96f1e6460c5..0bd6520329f6f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4243,6 +4243,9 @@ enum skb_ext_id {
#endif
#if IS_ENABLED(CONFIG_MPTCP)
SKB_EXT_MPTCP,
+#endif
+#if IS_ENABLED(CONFIG_MCTP_FLOWS)
+ SKB_EXT_MCTP,
#endif
SKB_EXT_NUM, /* must be last */
};
diff --git a/include/net/mctp.h b/include/net/mctp.h
index 23bec708f4c75..7a5ba801703c5 100644
--- a/include/net/mctp.h
+++ b/include/net/mctp.h
@@ -189,6 +189,13 @@ static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb)
return (void *)(skb->cb);
}
+/* If CONFIG_MCTP_FLOWS, we may add one of these as a SKB extension,
+ * indicating the flow to the device driver.
+ */
+struct mctp_flow {
+ struct mctp_sk_key *key;
+};
+
/* Route definition.
*
* These are held in the pernet->mctp.routes list, with RCU protection for
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 09b8cf8ab2347..67a9188d8a49c 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -70,6 +70,7 @@
#include <net/xfrm.h>
#include <net/mpls.h>
#include <net/mptcp.h>
+#include <net/mctp.h>
#include <net/page_pool.h>
#include <linux/uaccess.h>
@@ -4440,6 +4441,9 @@ static const u8 skb_ext_type_len[] = {
#if IS_ENABLED(CONFIG_MPTCP)
[SKB_EXT_MPTCP] = SKB_EXT_CHUNKSIZEOF(struct mptcp_ext),
#endif
+#if IS_ENABLED(CONFIG_MCTP_FLOWS)
+ [SKB_EXT_MCTP] = SKB_EXT_CHUNKSIZEOF(struct mctp_flow),
+#endif
};
static __always_inline unsigned int skb_ext_total_length(void)
@@ -4456,6 +4460,9 @@ static __always_inline unsigned int skb_ext_total_length(void)
#endif
#if IS_ENABLED(CONFIG_MPTCP)
skb_ext_type_len[SKB_EXT_MPTCP] +
+#endif
+#if IS_ENABLED(CONFIG_MCTP_FLOWS)
+ skb_ext_type_len[SKB_EXT_MCTP] +
#endif
0;
}
@@ -6529,6 +6536,14 @@ static void skb_ext_put_sp(struct sec_path *sp)
}
#endif
+#ifdef CONFIG_MCTP_FLOWS
+static void skb_ext_put_mctp(struct mctp_flow *flow)
+{
+ if (flow->key)
+ mctp_key_unref(flow->key);
+}
+#endif
+
void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
{
struct skb_ext *ext = skb->extensions;
@@ -6564,6 +6579,10 @@ void __skb_ext_put(struct skb_ext *ext)
if (__skb_ext_exist(ext, SKB_EXT_SEC_PATH))
skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH));
#endif
+#ifdef CONFIG_MCTP_FLOWS
+ if (__skb_ext_exist(ext, SKB_EXT_MCTP))
+ skb_ext_put_mctp(skb_ext_get_ptr(ext, SKB_EXT_MCTP));
+#endif
kmem_cache_free(skbuff_ext_cache, ext);
}
diff --git a/net/mctp/Kconfig b/net/mctp/Kconfig
index 868c92272cbd3..3a5c0e70da776 100644
--- a/net/mctp/Kconfig
+++ b/net/mctp/Kconfig
@@ -1,7 +1,7 @@
menuconfig MCTP
depends on NET
- tristate "MCTP core protocol support"
+ bool "MCTP core protocol support"
help
Management Component Transport Protocol (MCTP) is an in-system
protocol for communicating between management controllers and
@@ -16,3 +16,8 @@ config MCTP_TEST
bool "MCTP core tests" if !KUNIT_ALL_TESTS
depends on MCTP=y && KUNIT=y
default KUNIT_ALL_TESTS
+
+config MCTP_FLOWS
+ bool
+ depends on MCTP
+ select SKB_EXTENSIONS
--
GitLab