[MPTCP] [PATCH] mptcp: Re-factor expand_ack

[Peter Krystad <peter.krystad at linux.intel.com>]

[-- Attachment #1: Type: text/plain, Size: 1866 bytes --]

Modify this commit to handle separately-stored 32-bit data acks.

squashto: update per unacked sequence on pkt reception

Signed-off-by: Peter Krystad <peter.krystad(a)linux.intel.com>
---
 net/mptcp/options.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index bd1c3ba134ae..6ad0cdfa6de2 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -674,15 +674,16 @@ static bool check_fourth_ack(struct mptcp_subflow_context *subflow,
 	return true;
 }
 
-static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit)
+static u64 expand_ack(u64 old_ack, u32 cur_ack32)
 {
-	u32 old_ack32, cur_ack32;
-
-	if (use_64bit)
-		return cur_ack;
+	u32 old_ack32;
+	u64 cur_ack;
 
+	/* avoid ack expansion on update conflict, to reduce the risk of
+	 * wrongly expanding to a future ack sequence number, which is way
+	 * more dangerous than missing an ack
+	 */
 	old_ack32 = (u32)old_ack;
-	cur_ack32 = (u32)cur_ack;
 	cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32;
 	if (unlikely(before(cur_ack32, old_ack32)))
 		return cur_ack + (1LL << 32);
@@ -695,11 +696,10 @@ static void update_una(struct mptcp_sock *msk,
 	u64 new_snd_una, snd_una, old_snd_una = atomic64_read(&msk->snd_una);
 	u64 write_seq = READ_ONCE(msk->write_seq);
 
-	/* avoid ack expansion on update conflict, to reduce the risk of
-	 * wrongly expanding to a future ack sequence number, which is way
-	 * more dangerous than missing an ack
-	 */
-	new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
+	if (mp_opt->ack64)
+		new_snd_una = mp_opt->data_ack;
+	else
+		new_snd_una = expand_ack(old_snd_una, (u32)mp_opt->data_ack);
 
 	/* ACK for data not even sent yet? Ignore. */
 	if (after64(new_snd_una, write_seq))
-- 
2.17.2