[SRU][J][F][PATCH 3/8] hvcs: Fix hvcs port reference counting

[frank.heimes at canonical.com]

From: Brian King <brking at linux.vnet.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/2056373

The hvcs driver only ever gets two references to the port. One
at initialization time, and one at install time. Remove the code
that was trying to do multiple port puts for each open, which
would result in more puts than gets.

Signed-off-by: Brian King <brking at linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20230201195743.303163-2-brking@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit 6a9a733edd46732e906d976dc21a42dd361e53cc)
Signed-off-by: Frank Heimes <frank.heimes at canonical.com>
---
 drivers/tty/hvc/hvcs.c | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c
index 0c498b20d8cb..2e3327b23014 100644
--- a/drivers/tty/hvc/hvcs.c
+++ b/drivers/tty/hvc/hvcs.c
@@ -1246,12 +1246,9 @@ static void hvcs_hangup(struct tty_struct * tty)
 {
 	struct hvcs_struct *hvcsd = tty->driver_data;
 	unsigned long flags;
-	int temp_open_count;
 	int irq;
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
-	/* Preserve this so that we know how many kref refs to put */
-	temp_open_count = hvcsd->port.count;
 
 	/*
 	 * Don't kref put inside the spinlock because the destruction
@@ -1278,21 +1275,6 @@ static void hvcs_hangup(struct tty_struct * tty)
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
 
 	free_irq(irq, hvcsd);
-
-	/*
-	 * We need to kref_put() for every open_count we have since the
-	 * tty_hangup() function doesn't invoke a close per open connection on a
-	 * non-console device.
-	 */
-	while(temp_open_count) {
-		--temp_open_count;
-		/*
-		 * The final put will trigger destruction of the hvcs_struct.
-		 * NOTE:  If this hangup was signaled from user space then the
-		 * final put will never happen.
-		 */
-		tty_port_put(&hvcsd->port);
-	}
 }
 
 /*
-- 
2.25.1