Merge patch series "Add OP-TEE based RPMB driver for UFS devices"

Bean Huo <beanhuo@iokpp.de> says:

This patch series introduces OP-TEE based RPMB (Replay Protected
Memory Block) support for UFS devices, extending the kernel-level
secure storage capabilities that are currently available for eMMC
devices.

Previously, OP-TEE required a userspace supplicant to access RPMB
partitions, which created complex dependencies and reliability issues,
especially during early boot scenarios. Recent work by Linaro has
moved core supplicant functionality directly into the Linux kernel for
eMMC devices, eliminating userspace dependencies and enabling
immediate secure storage access. This series extends the same approach
to UFS devices, which are used in enterprise and mobile applications
that require secure storage capabilities.

Benefits:

 - Eliminates dependency on userspace supplicant for UFS RPMB access

 - Enables early boot secure storage access (e.g., fTPM, secure UEFI
   variables)

 - Provides kernel-level RPMB access as soon as UFS driver is
   initialized

 - Removes complex initramfs dependencies and boot ordering
   requirements

 - Ensures reliable and deterministic secure storage operations

 - Supports both built-in and modular fTPM configurations.

Prerequisites:
--------------

This patch series depends on commit 7e8242405b94 ("rpmb: move struct
rpmb_frame to common header") which has been merged into mainline
v6.18-rc2.

Link: https://patch.msgid.link/20251107230518.4060231-1-beanhuo@iokpp.de
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 15 insertions, 4 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index bb3576ac0ad7..b94efb3050d2 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2369,7 +2369,8 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
 				 u32 max_segs)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
-	u32 send_win, cong_win, limit, in_flight;
+	u32 send_win, cong_win, limit, in_flight, threshold;
+	u64 srtt_in_ns, expected_ack, how_far_is_the_ack;
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *head;
 	int win_divisor;
@@ -2431,9 +2432,19 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
 	head = tcp_rtx_queue_head(sk);
 	if (!head)
 		goto send_now;
-	delta = tp->tcp_clock_cache - head->tstamp;
-	/* If next ACK is likely to come too late (half srtt), do not defer */
-	if ((s64)(delta - (u64)NSEC_PER_USEC * (tp->srtt_us >> 4)) < 0)
+
+	srtt_in_ns = (u64)(NSEC_PER_USEC >> 3) * tp->srtt_us;
+	/* When is the ACK expected ? */
+	expected_ack = head->tstamp + srtt_in_ns;
+	/* How far from now is the ACK expected ? */
+	how_far_is_the_ack = expected_ack - tp->tcp_clock_cache;
+
+	/* If next ACK is likely to come too late,
+	 * ie in more than min(1ms, half srtt), do not defer.
+	 */
+	threshold = min(srtt_in_ns >> 1, NSEC_PER_MSEC);
+
+	if ((s64)(how_far_is_the_ack - threshold) > 0)
 		goto send_now;
 
 	/* Ok, it looks like it is advisable to defer.