netdev - [PATCH net v2 3/5] ptp: vmclock: Don't unregister misc device if it was not registered

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Message-Id: <20250207-vmclock-probe-v2-3-bc2fce0bdf07@linutronix.de>
Date: Fri, 07 Feb 2025 10:39:04 +0100
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: David Woodhouse <dwmw2@...radead.org>, 
 Richard Cochran <richardcochran@...il.com>, 
 Andrew Lunn <andrew+netdev@...n.ch>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Cc: Mateusz Polchlopek <mateusz.polchlopek@...el.com>, 
 David Woodhouse <dwmw@...zon.co.uk>, netdev@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 Thomas Weißschuh <thomas.weissschuh@...utronix.de>, 
 stable@...r.kernel.org
Subject: [PATCH net v2 3/5] ptp: vmclock: Don't unregister misc device if
 it was not registered

vmclock_remove() tries to detect the successful registration of the misc
device based on the value of its minor value.
However that check is incorrect if the misc device registration was not
attempted in the first place.

Always initialize the minor number, so the check works properly.

Fixes: 205032724226 ("ptp: Add support for the AMZNC10C 'vmclock' device")
Cc: stable@...r.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Acked-by: Richard Cochran <richardcochran@...il.com>
Reviewed-by: David Woodhouse <dwmw@...zon.co.uk>
---
 drivers/ptp/ptp_vmclock.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_vmclock.c b/drivers/ptp/ptp_vmclock.c
index 1ba30a2da570fb4d1ec9db72820bf1781dfa9655..9b8bd626a397313433908fcc838edf8ffc3ecc98 100644
--- a/drivers/ptp/ptp_vmclock.c
+++ b/drivers/ptp/ptp_vmclock.c
@@ -550,6 +550,8 @@ static int vmclock_probe(struct platform_device *pdev)
 		goto out;
 	}

+	st->miscdev.minor = MISC_DYNAMIC_MINOR;
+
 	/*
 	 * If the structure is big enough, it can be mapped to userspace.
 	 * Theoretically a guest OS even using larger pages could still
@@ -557,7 +559,6 @@ static int vmclock_probe(struct platform_device *pdev)
 	 * cross that bridge if/when we come to it.
 	 */
 	if (le32_to_cpu(st->clk->size) >= PAGE_SIZE) {
-		st->miscdev.minor = MISC_DYNAMIC_MINOR;
 		st->miscdev.fops = &vmclock_miscdev_fops;
 		st->miscdev.name = st->name;

-- 
2.48.1