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From: Stuart Hayes <stuart.w.hayes@gmail.com>
To: linux-kernel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Tanjore Suresh <tansuresh@google.com>,
	Martin Belanger <Martin.Belanger@dell.com>,
	Oliver O'Halloran <oohall@gmail.com>,
	Daniel Wagner <dwagner@suse.de>,
	Keith Busch <kbusch@kernel.org>,
	Lukas Wunner <lukas@wunner.de>,
	David Jeffery <djeffery@redhat.com>,
	Jeremy Allison <jallison@ciq.com>,
	Jens Axboe <axboe@fb.com>,
	Christoph Hellwig <hch@lst.de>,
	Sagi Grimberg <sagi@grimberg.me>,
	linux-nvme@lists.infradead.org
Cc: Stuart Hayes <stuart.w.hayes@gmail.com>
Subject: [PATCH v6 1/4] driver core: don't always lock parent in shutdown
Date: Thu, 16 May 2024 10:49:17 -0500
Message-Id: <20240516154920.221445-2-stuart.w.hayes@gmail.com>
In-Reply-To: <20240516154920.221445-1-stuart.w.hayes@gmail.com>
References: <20240516154920.221445-1-stuart.w.hayes@gmail.com>
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Don't lock a parent device unless it is needed in device_shutdown. This
is in preparation for making device shutdown asynchronous, when it will
be needed to allow children of a common parent to shut down
simultaneously.

Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: David Jeffery <djeffery@redhat.com>
---
 drivers/base/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 5f4e03336e68..e63177314e86 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -4856,7 +4856,7 @@ void device_shutdown(void)
 		spin_unlock(&devices_kset->list_lock);
 
 		/* hold lock to avoid race with probe/release */
-		if (parent)
+		if (parent && dev->bus && dev->bus->need_parent_lock)
 			device_lock(parent);
 		device_lock(dev);
 
@@ -4880,7 +4880,7 @@ void device_shutdown(void)
 		}
 
 		device_unlock(dev);
-		if (parent)
+		if (parent && dev->bus && dev->bus->need_parent_lock)
 			device_unlock(parent);
 
 		put_device(dev);
-- 
2.39.3