[PATCH v3 net-next] net: use get_random_u{16,32,64}() where appropriate

[PATCH v3 net-next] net: use get_random_u{16,32,64}() where appropriate

[David Carlier]

Use the typed random integer helpers instead of
get_random_bytes() when filling a single integer variable.
The helpers return the value directly, require no pointer
or size argument, and better express intent.

Skipped sites writing into __be16 fields (netdevsim) where
a direct assignment would trigger sparse endianness warnings.

Signed-off-by: David Carlier <devnexen@gmail.com>
---
 drivers/net/netdevsim/psample.c | 4 ++--
 net/ceph/auth_x.c               | 2 +-
 net/core/net_namespace.c        | 2 +-
 net/mac80211/mesh_plink.c       | 2 +-
 net/mptcp/subflow.c             | 4 ++--
 net/openvswitch/flow_table.c    | 2 +-
 net/sctp/sm_make_chunk.c        | 4 ++--
 net/tipc/node.c                 | 2 +-
 8 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/net/netdevsim/psample.c b/drivers/net/netdevsim/psample.c
index 47d24bc64ee4..717d157c3ae2 100644
--- a/drivers/net/netdevsim/psample.c
+++ b/drivers/net/netdevsim/psample.c
@@ -94,7 +94,7 @@ static void nsim_dev_psample_md_prepare(const struct nsim_dev_psample *psample,
 	if (psample->out_tc_occ_max) {
 		u64 out_tc_occ;
 
-		get_random_bytes(&out_tc_occ, sizeof(u64));
+		out_tc_occ = get_random_u64();
 		md->out_tc_occ = out_tc_occ & (psample->out_tc_occ_max - 1);
 		md->out_tc_occ_valid = 1;
 	}
@@ -102,7 +102,7 @@ static void nsim_dev_psample_md_prepare(const struct nsim_dev_psample *psample,
 	if (psample->latency_max) {
 		u64 latency;
 
-		get_random_bytes(&latency, sizeof(u64));
+		latency = get_random_u64();
 		md->latency = latency & (psample->latency_max - 1);
 		md->latency_valid = 1;
 	}
diff --git a/net/ceph/auth_x.c b/net/ceph/auth_x.c
index 692e0b868822..936b43ae4a95 100644
--- a/net/ceph/auth_x.c
+++ b/net/ceph/auth_x.c
@@ -571,7 +571,7 @@ static int ceph_x_build_request(struct ceph_auth_client *ac,
 			blob = enc_buf + SHA256_DIGEST_SIZE;
 		}
 
-		get_random_bytes(&auth->client_challenge, sizeof(u64));
+		auth->client_challenge = get_random_u64();
 		blob->client_challenge = auth->client_challenge;
 		blob->server_challenge = cpu_to_le64(xi->server_challenge);
 
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 1057d16d5dd2..deb8b2ec5674 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -411,7 +411,7 @@ static __net_init int preinit_net(struct net *net, struct user_namespace *user_n
 	ref_tracker_dir_init(&net->refcnt_tracker, 128, "net_refcnt");
 	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net_notrefcnt");
 
-	get_random_bytes(&net->hash_mix, sizeof(u32));
+	net->hash_mix = get_random_u32();
 	net->dev_base_seq = 1;
 	net->user_ns = user_ns;
 
diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index 803106fc3134..7cbab90c8784 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -712,7 +712,7 @@ void mesh_plink_timer(struct timer_list *t)
 				"Mesh plink for %pM (retry, timeout): %d %d\n",
 				sta->sta.addr, sta->mesh->plink_retries,
 				sta->mesh->plink_timeout);
-			get_random_bytes(&rand, sizeof(u32));
+			rand = get_random_u32();
 			sta->mesh->plink_timeout = sta->mesh->plink_timeout +
 					     rand % sta->mesh->plink_timeout;
 			++sta->mesh->plink_retries;
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 5cfe19990f31..1a7736145dbc 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -72,7 +72,7 @@ static void subflow_req_create_thmac(struct mptcp_subflow_request_sock *subflow_
 	struct mptcp_sock *msk = subflow_req->msk;
 	u8 hmac[SHA256_DIGEST_SIZE];
 
-	get_random_bytes(&subflow_req->local_nonce, sizeof(u32));
+	subflow_req->local_nonce = get_random_u32();
 
 	subflow_generate_hmac(READ_ONCE(msk->local_key),
 			      READ_ONCE(msk->remote_key),
@@ -1639,7 +1639,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_pm_local *local,
 	ssk = sf->sk;
 	subflow = mptcp_subflow_ctx(ssk);
 	do {
-		get_random_bytes(&subflow->local_nonce, sizeof(u32));
+		subflow->local_nonce = get_random_u32();
 	} while (!subflow->local_nonce);
 
 	/* if 'IPADDRANY', the ID will be set later, after the routing */
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 61c6a5f77c2e..67d5b8c0fe79 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -167,7 +167,7 @@ static struct table_instance *table_instance_alloc(int new_size)
 
 	ti->n_buckets = new_size;
 	ti->node_ver = 0;
-	get_random_bytes(&ti->hash_seed, sizeof(u32));
+	ti->hash_seed = get_random_u32();
 
 	return ti;
 }
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 2c0017d058d4..de86ac088289 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2727,7 +2727,7 @@ __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
 	__u32 x;
 
 	do {
-		get_random_bytes(&x, sizeof(__u32));
+		x = get_random_u32();
 	} while (x == 0);
 
 	return x;
@@ -2738,7 +2738,7 @@ __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
 {
 	__u32 retval;
 
-	get_random_bytes(&retval, sizeof(__u32));
+	retval = get_random_u32();
 	return retval;
 }
 
diff --git a/net/tipc/node.c b/net/tipc/node.c
index af442a5ef8f3..97aa970a0d83 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -1275,7 +1275,7 @@ void tipc_node_check_dest(struct net *net, u32 addr,
 			goto exit;
 
 		if_name = strchr(b->name, ':') + 1;
-		get_random_bytes(&session, sizeof(u16));
+		session = get_random_u16();
 		if (!tipc_link_create(net, if_name, b->identity, b->tolerance,
 				      b->net_plane, b->mtu, b->priority,
 				      b->min_win, b->max_win, session,
-- 
2.53.0

Re: [PATCH v3 net-next] net: use get_random_u{16,32,64}() where appropriate

[Andrew Lunn]

On Sun, Apr 05, 2026 at 04:48:16PM +0100, David Carlier wrote:
> Use the typed random integer helpers instead of
> get_random_bytes() when filling a single integer variable.
> The helpers return the value directly, require no pointer
> or size argument, and better express intent.
> 
> Skipped sites writing into __be16 fields (netdevsim) where
> a direct assignment would trigger sparse endianness warnings.
> 
> Signed-off-by: David Carlier <devnexen@gmail.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH v3 net-next] net: use get_random_u{16,32,64}() where appropriate

[Matthieu Baerts]

Hi David,

On 05/04/2026 17:48, David Carlier wrote:
> Use the typed random integer helpers instead of
> get_random_bytes() when filling a single integer variable.
> The helpers return the value directly, require no pointer
> or size argument, and better express intent.

Regarding the modifications in net/mptcp, it looks good to me:

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> # net/mptcp

> Skipped sites writing into __be16 fields (netdevsim) where
> a direct assignment would trigger sparse endianness warnings.

Note that the AI reviews are mentioning that auth->client_challenge from
net/ceph/auth_x.c is declared as __le64, and it might then also cause
sparse warnings:

  https://sashiko.dev/#/patchset/20260405154816.4774-1-devnexen%40gmail.com


It looks like they are right:

  $ make C=1 net/ceph/auth_x.o
  net/ceph/auth_x.c:574:40: warning: incorrect type in assignment (different base types)
  net/ceph/auth_x.c:574:40:    expected restricted __le64 [usertype] client_challenge
  net/ceph/auth_x.c:574:40:    got unsigned long long


Note that the Netdev CI currently doesn't check sparse warnings:

  https://github.com/linux-netdev/nipa/issues/76

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Re: [PATCH v3 net-next] net: use get_random_u{16,32,64}() where appropriate

[David CARLIER]

Hi Mathieu yes this is indeed a valid point, will address is for next
time. Cheers

On Mon, 6 Apr 2026 at 15:13, Matthieu Baerts <matttbe@kernel.org> wrote:
>
> Hi David,
>
> On 05/04/2026 17:48, David Carlier wrote:
> > Use the typed random integer helpers instead of
> > get_random_bytes() when filling a single integer variable.
> > The helpers return the value directly, require no pointer
> > or size argument, and better express intent.
>
> Regarding the modifications in net/mptcp, it looks good to me:
>
> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> # net/mptcp
>
> > Skipped sites writing into __be16 fields (netdevsim) where
> > a direct assignment would trigger sparse endianness warnings.
>
> Note that the AI reviews are mentioning that auth->client_challenge from
> net/ceph/auth_x.c is declared as __le64, and it might then also cause
> sparse warnings:
>
>   https://sashiko.dev/#/patchset/20260405154816.4774-1-devnexen%40gmail.com
>
>
> It looks like they are right:
>
>   $ make C=1 net/ceph/auth_x.o
>   net/ceph/auth_x.c:574:40: warning: incorrect type in assignment (different base types)
>   net/ceph/auth_x.c:574:40:    expected restricted __le64 [usertype] client_challenge
>   net/ceph/auth_x.c:574:40:    got unsigned long long
>
>
> Note that the Netdev CI currently doesn't check sparse warnings:
>
>   https://github.com/linux-netdev/nipa/issues/76
>
> Cheers,
> Matt
> --
> Sponsored by the NGI0 Core fund.
>