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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Parav Pandit <parav@mellanox.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Sasha Levin <sashal@kernel.org>,
	kvm@vger.kernel.org
Subject: [PATCH AUTOSEL 4.14 191/371] vfio/mdev: Fix aborting mdev child device removal if one fails
Date: Thu, 16 Jan 2020 12:21:03 -0500
Message-ID: <20200116172403.18149-134-sashal@kernel.org> (raw)
In-Reply-To: <20200116172403.18149-1-sashal@kernel.org>

From: Parav Pandit <parav@mellanox.com>

[ Upstream commit 6093e348a5e2475c5bb2e571346460f939998670 ]

device_for_each_child() stops executing callback function for remaining
child devices, if callback hits an error.
Each child mdev device is independent of each other.
While unregistering parent device, mdev core must remove all child mdev
devices.
Therefore, mdev_device_remove_cb() always returns success so that
device_for_each_child doesn't abort if one child removal hits error.

While at it, improve remove and unregister functions for below simplicity.

There isn't need to pass forced flag pointer during mdev parent
removal which invokes mdev_device_remove(). So simplify the flow.

mdev_device_remove() is called from two paths.
1. mdev_unregister_driver()
     mdev_device_remove_cb()
       mdev_device_remove()
2. remove_store()
     mdev_device_remove()

Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/vfio/mdev/mdev_core.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 8cfa71230877..e052f62fdea7 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -150,10 +150,10 @@ static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove)
 
 static int mdev_device_remove_cb(struct device *dev, void *data)
 {
-	if (!dev_is_mdev(dev))
-		return 0;
+	if (dev_is_mdev(dev))
+		mdev_device_remove(dev, true);
 
-	return mdev_device_remove(dev, data ? *(bool *)data : true);
+	return 0;
 }
 
 /*
@@ -241,7 +241,6 @@ EXPORT_SYMBOL(mdev_register_device);
 void mdev_unregister_device(struct device *dev)
 {
 	struct mdev_parent *parent;
-	bool force_remove = true;
 
 	mutex_lock(&parent_list_lock);
 	parent = __find_parent_device(dev);
@@ -255,8 +254,7 @@ void mdev_unregister_device(struct device *dev)
 	list_del(&parent->next);
 	class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
 
-	device_for_each_child(dev, (void *)&force_remove,
-			      mdev_device_remove_cb);
+	device_for_each_child(dev, NULL, mdev_device_remove_cb);
 
 	parent_remove_sysfs_files(parent);
 
-- 
2.20.1


      parent reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116172403.18149-1-sashal@kernel.org>
2020-01-16 17:19 ` [PATCH AUTOSEL 4.14 101/371] vfio_pci: Enable memory accesses before calling pci_map_rom Sasha Levin
2020-01-16 17:21 ` [PATCH AUTOSEL 4.14 190/371] vfio/mdev: Avoid release parent reference during error path Sasha Levin
2020-01-16 17:21 ` Sasha Levin [this message]

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