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neighbour: Annotate access to struct pneigh_entry.{flags,protocol}.

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We will convert pneigh readers to RCU, and its flags and protocol
will be read locklessly.

Let's annotate the access to the two fields.

Note that all access to pn->permanent is under RTNL (neigh_add()
and pneigh_ifdown_and_unlock()), so WRITE_ONCE() and READ_ONCE()
are not needed.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250716221221.442239-9-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2025-07-16 22:08:13 +00:00 committed by Jakub Kicinski
parent d539d8fbd8
commit cc03492c7b
1 changed files with 8 additions and 5 deletions
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13
net/core/neighbour.c
View File

@ -2044,10 +2044,10 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
err = -ENOBUFS;
pn = pneigh_create(tbl, net, dst, dev);
if (pn) {
pn->flags = ndm_flags;
WRITE_ONCE(pn->flags, ndm_flags);
pn->permanent = !!(ndm->ndm_state & NUD_PERMANENT);
if (protocol)
pn->protocol = protocol;
WRITE_ONCE(pn->protocol, protocol);
err = 0;
}
goto out;
@ -2678,13 +2678,15 @@ static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
u32 neigh_flags, neigh_flags_ext;
struct nlmsghdr *nlh;
struct ndmsg *ndm;
u8 protocol;
nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
if (nlh == NULL)
return -EMSGSIZE;
neigh_flags_ext = pn->flags >> NTF_EXT_SHIFT;
neigh_flags = pn->flags & NTF_OLD_MASK;
neigh_flags = READ_ONCE(pn->flags);
neigh_flags_ext = neigh_flags >> NTF_EXT_SHIFT;
neigh_flags &= NTF_OLD_MASK;
ndm = nlmsg_data(nlh);
ndm->ndm_family = tbl->family;
@ -2698,7 +2700,8 @@ static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
if (nla_put(skb, NDA_DST, tbl->key_len, pn->key))
goto nla_put_failure;
if (pn->protocol && nla_put_u8(skb, NDA_PROTOCOL, pn->protocol))
protocol = READ_ONCE(pn->protocol);
if (protocol && nla_put_u8(skb, NDA_PROTOCOL, protocol))
goto nla_put_failure;
if (neigh_flags_ext && nla_put_u32(skb, NDA_FLAGS_EXT, neigh_flags_ext))
goto nla_put_failure;