Merge tag 'i2c-host-6.13-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux into i2c/for-mergewindow

i2c-host updates for v6.13, part 1

Major Improvements and Refactoring:

 - All controllers using the 'remove_new' callback have been
   reverted to use the 'remove' callback.

 - Intel SCH controller underwent significant refactoring,
   this brings love and a modern look to the driver.

 - PIIX4 driver refactored to enable usage by other drivers
   (e.g., AMD ASF).

 - iMX/MXC improved message handling to reduce protocol overhead:
     Refactored DMA/non-DMA read/write and bus polling mechanisms
     to achieve this.

 - ACPI documentation for PIIX4.

New Features:

 - i2c-cadence added support for atomic transfers.
 - Qualcomm CII added support for a 32MHz serial engine clock.

Deprecated Features:

 - Dropped outdated support for AMD756 S4882 and NFORCE2 S4985. If
   somebody misses this, Jean will rewrite support using the proper
   i2c mux framework.

New Hardware Support:

 - Added support for:
   - Intel Panther Lake (new ID)
   - AMD ASF (new driver)
   - S32G2/S32G3 SoCs (new ID)
   - Realtek RTL I2C Controller (new driver)
   - HJMC01 DesignWare ACPI HID (new ID)
   - PIC64GX to Microchip Core (new ID)
   - Qualcomm SDM670 to Qualcomm CCI (new ID)

1 files changed, 38 insertions, 4 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index cc05ec1faac89..2d844e1f867f0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2473,8 +2473,22 @@ static bool tcp_skb_spurious_retrans(const struct tcp_sock *tp,
  */
 static inline bool tcp_packet_delayed(const struct tcp_sock *tp)
 {
-	return tp->retrans_stamp &&
-	       tcp_tsopt_ecr_before(tp, tp->retrans_stamp);
+	const struct sock *sk = (const struct sock *)tp;
+
+	if (tp->retrans_stamp &&
+	    tcp_tsopt_ecr_before(tp, tp->retrans_stamp))
+		return true;  /* got echoed TS before first retransmission */
+
+	/* Check if nothing was retransmitted (retrans_stamp==0), which may
+	 * happen in fast recovery due to TSQ. But we ignore zero retrans_stamp
+	 * in TCP_SYN_SENT, since when we set FLAG_SYN_ACKED we also clear
+	 * retrans_stamp even if we had retransmitted the SYN.
+	 */
+	if (!tp->retrans_stamp &&	   /* no record of a retransmit/SYN? */
+	    sk->sk_state != TCP_SYN_SENT)  /* not the FLAG_SYN_ACKED case? */
+		return true;  /* nothing was retransmitted */
+
+	return false;
 }
 
 /* Undo procedures. */
@@ -2508,6 +2522,16 @@ static bool tcp_any_retrans_done(const struct sock *sk)
 	return false;
 }
 
+/* If loss recovery is finished and there are no retransmits out in the
+ * network, then we clear retrans_stamp so that upon the next loss recovery
+ * retransmits_timed_out() and timestamp-undo are using the correct value.
+ */
+static void tcp_retrans_stamp_cleanup(struct sock *sk)
+{
+	if (!tcp_any_retrans_done(sk))
+		tcp_sk(sk)->retrans_stamp = 0;
+}
+
 static void DBGUNDO(struct sock *sk, const char *msg)
 {
 #if FASTRETRANS_DEBUG > 1
@@ -2875,6 +2899,9 @@ void tcp_enter_recovery(struct sock *sk, bool ece_ack)
 	struct tcp_sock *tp = tcp_sk(sk);
 	int mib_idx;
 
+	/* Start the clock with our fast retransmit, for undo and ETIMEDOUT. */
+	tcp_retrans_stamp_cleanup(sk);
+
 	if (tcp_is_reno(tp))
 		mib_idx = LINUX_MIB_TCPRENORECOVERY;
 	else
@@ -6657,10 +6684,17 @@ static void tcp_rcv_synrecv_state_fastopen(struct sock *sk)
 	if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss && !tp->packets_out)
 		tcp_try_undo_recovery(sk);
 
-	/* Reset rtx states to prevent spurious retransmits_timed_out() */
 	tcp_update_rto_time(tp);
-	tp->retrans_stamp = 0;
 	inet_csk(sk)->icsk_retransmits = 0;
+	/* In tcp_fastopen_synack_timer() on the first SYNACK RTO we set
+	 * retrans_stamp but don't enter CA_Loss, so in case that happened we
+	 * need to zero retrans_stamp here to prevent spurious
+	 * retransmits_timed_out(). However, if the ACK of our SYNACK caused us
+	 * to enter CA_Recovery then we need to leave retrans_stamp as it was
+	 * set entering CA_Recovery, for correct retransmits_timed_out() and
+	 * undo behavior.
+	 */
+	tcp_retrans_stamp_cleanup(sk);
 
 	/* Once we leave TCP_SYN_RECV or TCP_FIN_WAIT_1,
 	 * we no longer need req so release it.