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From: Adrian Hunter <adrian.hunter@intel.com>
To: alexandre.belloni@bootlin.com
Cc: Frank.Li@nxp.com, Adrian Ng Ho Yin <adrian.ho.yin.ng@altera.com>,
	linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] i3c: master: Update dev_nack_retry_count under maintenance lock
Date: Tue, 16 Jun 2026 14:37:50 +0300	[thread overview]
Message-ID: <20260616113752.196140-2-adrian.hunter@intel.com> (raw)
In-Reply-To: <20260616113752.196140-1-adrian.hunter@intel.com>

Protect master->dev_nack_retry_count against concurrent sysfs updates
by updating it while holding the bus maintenance lock.

Consequently, combine adjacent return statements into one.

For consistency, read dev_nack_retry_count while holding the bus normaluse
lock.

Fixes: b58f47eb39268 ("i3c: add sysfs entry and attribute for Device NACK Retry count")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/i3c/master.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 367e0d6d4a64..66cf5d3bd987 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -744,7 +744,14 @@ static DEVICE_ATTR_RW(hotjoin);
 static ssize_t dev_nack_retry_count_show(struct device *dev,
 					 struct device_attribute *attr, char *buf)
 {
-	return sysfs_emit(buf, "%u\n", dev_to_i3cmaster(dev)->dev_nack_retry_count);
+	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(i3cbus);
+	ret = sysfs_emit(buf, "%u\n", dev_to_i3cmaster(dev)->dev_nack_retry_count);
+	i3c_bus_normaluse_unlock(i3cbus);
+
+	return ret;
 }
 
 static ssize_t dev_nack_retry_count_store(struct device *dev,
@@ -762,14 +769,11 @@ static ssize_t dev_nack_retry_count_store(struct device *dev,
 
 	i3c_bus_maintenance_lock(i3cbus);
 	ret = master->ops->set_dev_nack_retry(master, val);
+	if (!ret)
+		master->dev_nack_retry_count = val;
 	i3c_bus_maintenance_unlock(i3cbus);
 
-	if (ret)
-		return ret;
-
-	master->dev_nack_retry_count = val;
-
-	return count;
+	return ret ?: count;
 }
 
 static DEVICE_ATTR_RW(dev_nack_retry_count);
-- 
2.51.0


-- 
linux-i3c mailing list
linux-i3c@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-i3c

WARNING: multiple messages have this Message-ID (diff)
From: Adrian Hunter <adrian.hunter@intel.com>
To: alexandre.belloni@bootlin.com
Cc: Frank.Li@nxp.com, Adrian Ng Ho Yin <adrian.ho.yin.ng@altera.com>,
	linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] i3c: master: Update dev_nack_retry_count under maintenance lock
Date: Tue, 16 Jun 2026 14:37:50 +0300	[thread overview]
Message-ID: <20260616113752.196140-2-adrian.hunter@intel.com> (raw)
In-Reply-To: <20260616113752.196140-1-adrian.hunter@intel.com>

Protect master->dev_nack_retry_count against concurrent sysfs updates
by updating it while holding the bus maintenance lock.

Consequently, combine adjacent return statements into one.

For consistency, read dev_nack_retry_count while holding the bus normaluse
lock.

Fixes: b58f47eb39268 ("i3c: add sysfs entry and attribute for Device NACK Retry count")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/i3c/master.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 367e0d6d4a64..66cf5d3bd987 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -744,7 +744,14 @@ static DEVICE_ATTR_RW(hotjoin);
 static ssize_t dev_nack_retry_count_show(struct device *dev,
 					 struct device_attribute *attr, char *buf)
 {
-	return sysfs_emit(buf, "%u\n", dev_to_i3cmaster(dev)->dev_nack_retry_count);
+	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(i3cbus);
+	ret = sysfs_emit(buf, "%u\n", dev_to_i3cmaster(dev)->dev_nack_retry_count);
+	i3c_bus_normaluse_unlock(i3cbus);
+
+	return ret;
 }
 
 static ssize_t dev_nack_retry_count_store(struct device *dev,
@@ -762,14 +769,11 @@ static ssize_t dev_nack_retry_count_store(struct device *dev,
 
 	i3c_bus_maintenance_lock(i3cbus);
 	ret = master->ops->set_dev_nack_retry(master, val);
+	if (!ret)
+		master->dev_nack_retry_count = val;
 	i3c_bus_maintenance_unlock(i3cbus);
 
-	if (ret)
-		return ret;
-
-	master->dev_nack_retry_count = val;
-
-	return count;
+	return ret ?: count;
 }
 
 static DEVICE_ATTR_RW(dev_nack_retry_count);
-- 
2.51.0


  reply	other threads:[~2026-06-16 11:38 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-16 11:37 [PATCH 0/3] i3c: master: Small fixes for dev_nack_retry_count Adrian Hunter
2026-06-16 11:37 ` Adrian Hunter
2026-06-16 11:37 ` Adrian Hunter [this message]
2026-06-16 11:37   ` [PATCH 1/3] i3c: master: Update dev_nack_retry_count under maintenance lock Adrian Hunter
2026-06-16 11:51   ` sashiko-bot
2026-06-16 13:30     ` Adrian Hunter
2026-06-16 16:55   ` Frank Li
2026-06-16 16:55     ` Frank Li
2026-06-16 11:37 ` [PATCH 2/3] i3c: master: Add missing runtime PM get in dev_nack_retry_count_store() Adrian Hunter
2026-06-16 11:37   ` Adrian Hunter
2026-06-16 11:51   ` sashiko-bot
2026-06-16 13:46     ` Adrian Hunter
2026-06-16 16:56   ` Frank Li
2026-06-16 16:56     ` Frank Li
2026-06-16 11:37 ` [PATCH 3/3] i3c: master: Use unsigned int for dev_nack_retry_count consistently Adrian Hunter
2026-06-16 11:37   ` Adrian Hunter
2026-06-16 16:58   ` Frank Li
2026-06-16 16:58     ` Frank Li

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