linux-kernel - [PATCH AUTOSEL 4.19 29/38] media: cec-adap.c: fix is

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Date:   Mon, 30 May 2022 09:49:15 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Hans Verkuil <hverkuil-cisco@...all.nl>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Sasha Levin <sashal@...nel.org>, linux-media@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 29/38] media: cec-adap.c: fix is_configuring state

From: Hans Verkuil <hverkuil-cisco@...all.nl>

[ Upstream commit 59267fc34f4900dcd2ec3295f6be04b79aee2186 ]

If an adapter is trying to claim a free logical address then it is
in the 'is_configuring' state. If during that process the cable is
disconnected (HPD goes low, which in turn invalidates the physical
address), then cec_adap_unconfigure() is called, and that set the
is_configuring boolean to false, even though the thread that's
trying to claim an LA is still running.

Don't touch the is_configuring bool in cec_adap_unconfigure(), it
will eventually be cleared by the thread. By making that change
the cec_config_log_addr() function also had to change: it was
aborting if is_configuring became false (since that is what
cec_adap_unconfigure() did), but that no longer works. Instead
check if the physical address is invalid. That is a much
more appropriate check anyway.

This fixes a bug where the the adapter could be disabled even
though the device was still configuring. This could cause POLL
transmits to time out.

Signed-off-by: Hans Verkuil <hverkuil-cisco@...all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/cec/cec-adap.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
index 5eeadab15a5f..a42043379d67 100644
--- a/drivers/media/cec/cec-adap.c
+++ b/drivers/media/cec/cec-adap.c
@@ -1218,7 +1218,7 @@ static int cec_config_log_addr(struct cec_adapter *adap,
 		 * While trying to poll the physical address was reset
 		 * and the adapter was unconfigured, so bail out.
 		 */
-		if (!adap->is_configuring)
+		if (adap->phys_addr == CEC_PHYS_ADDR_INVALID)
 			return -EINTR;

 		if (err)
@@ -1276,7 +1276,6 @@ static void cec_adap_unconfigure(struct cec_adapter *adap)
 	    adap->phys_addr != CEC_PHYS_ADDR_INVALID)
 		WARN_ON(adap->ops->adap_log_addr(adap, CEC_LOG_ADDR_INVALID));
 	adap->log_addrs.log_addr_mask = 0;
-	adap->is_configuring = false;
 	adap->is_configured = false;
 	memset(adap->phys_addrs, 0xff, sizeof(adap->phys_addrs));
 	cec_flush(adap);
@@ -1469,9 +1468,10 @@ static int cec_config_thread_func(void *arg)
 	for (i = 0; i < las->num_log_addrs; i++)
 		las->log_addr[i] = CEC_LOG_ADDR_INVALID;
 	cec_adap_unconfigure(adap);
+	adap->is_configuring = false;
 	adap->kthread_config = NULL;
-	mutex_unlock(&adap->lock);
 	complete(&adap->config_completion);
+	mutex_unlock(&adap->lock);
 	return 0;
 }

-- 
2.35.1