[openwrt/openwrt] realtek: pcs: Fix overflow in rtpcs_930x_sds_clock_wait

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/d5fec0b125a31c148cf398b5106d49f361bd377b

commit d5fec0b125a31c148cf398b5106d49f361bd377b
Author: Sven Eckelmann <sven at narfation.org>
AuthorDate: Sun Nov 23 15:25:05 2025 +0100

    realtek: pcs: Fix overflow in rtpcs_930x_sds_clock_wait
    
    It can happen that the calculation `start + (HZ / 1000) * timeout`
    overflows `unsigned long`. This must be handled correctly to avoid too long
    waits. Luckily, the `time_before()` helper already does this.
    
    Signed-off-by: Sven Eckelmann <sven at narfation.org>
    Link: https://github.com/openwrt/openwrt/pull/20906
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c b/target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c
index cced6d5168..482bc2e08e 100644
--- a/target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c
+++ b/target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c
@@ -685,13 +685,14 @@ static int rtpcs_930x_sds_clock_wait(struct rtpcs_ctrl *ctrl, int timeout)
 {
 	u32 v;
 	unsigned long start = jiffies;
+	unsigned long end = start + (HZ / 1000) * timeout;
 
 	do {
 		rtpcs_sds_write_bits(ctrl, 2, 0x1f, 0x2, 15, 0, 53);
 		v = rtpcs_sds_read_bits(ctrl, 2, 0x1f, 20, 5, 4);
 		if (v == 3)
 			return 0;
-	} while (jiffies < start + (HZ / 1000) * timeout);
+	} while (time_before(jiffies, end));
 
 	return 1;
 }