[PATCH 07/11] staging: fsl-mc: fix asymmetry in destroy of mc_io

[Stuart Yoder]

From: Bharat Bhushan <bharat.bhus...@nxp.com>

An mc_io represents a mapped MC portal.  Previously, an mc_io was
created for the root dprc in fsl_mc_bus_probe() and for child dprcs
in dprc_probe().  But the free of that data structure happened in the
general bus remove callback.  This asymmetry resulted in some bugs due
to unwanted destroys of mc_io object in some scenarios (e.g. vfio).

Fix this bug by making things symmetric-- mc_io created in
fsl_mc_bus_probe() is freed in fsl_mc_bus_remove().  The mc_io created
in dprc_probe() is freed in dprc_remove().

Signed-off-by: Bharat Bhushan <bharat.bhus...@nxp.com>
[Stuart: added check for root dprc and reworded commit message]
Signed-off-by: Stuart Yoder <stuart.yo...@nxp.com>
---
 drivers/staging/fsl-mc/bus/dprc-driver.c | 5 +++++
 drivers/staging/fsl-mc/bus/mc-bus.c      | 8 ++++----
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/fsl-mc/bus/dprc-driver.c 
b/drivers/staging/fsl-mc/bus/dprc-driver.c
index f865d18..1a6bcc4 100644
--- a/drivers/staging/fsl-mc/bus/dprc-driver.c
+++ b/drivers/staging/fsl-mc/bus/dprc-driver.c
@@ -801,6 +801,11 @@ static int dprc_remove(struct fsl_mc_device *mc_dev)
                dev_set_msi_domain(&mc_dev->dev, NULL);
        }
 
+       if (!fsl_mc_is_root_dprc(&mc_dev->dev)) {
+               fsl_destroy_mc_io(mc_dev->mc_io);
+               mc_dev->mc_io = NULL;
+       }
+
        dev_info(&mc_dev->dev, "DPRC device unbound from driver");
        return 0;
 }
diff --git a/drivers/staging/fsl-mc/bus/mc-bus.c 
b/drivers/staging/fsl-mc/bus/mc-bus.c
index a49186e..db3afdb 100644
--- a/drivers/staging/fsl-mc/bus/mc-bus.c
+++ b/drivers/staging/fsl-mc/bus/mc-bus.c
@@ -579,10 +579,6 @@ void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
 
        if (strcmp(mc_dev->obj_desc.type, "dprc") == 0) {
                mc_bus = to_fsl_mc_bus(mc_dev);
-               if (mc_dev->mc_io) {
-                       fsl_destroy_mc_io(mc_dev->mc_io);
-                       mc_dev->mc_io = NULL;
-               }
 
                if (fsl_mc_is_root_dprc(&mc_dev->dev)) {
                        if (atomic_read(&root_dprc_count) > 0)
@@ -810,6 +806,10 @@ static int fsl_mc_bus_remove(struct platform_device *pdev)
                return -EINVAL;
 
        fsl_mc_device_remove(mc->root_mc_bus_dev);
+
+       fsl_destroy_mc_io(mc->root_mc_bus_dev->mc_io);
+       mc->root_mc_bus_dev->mc_io = NULL;
+
        dev_info(&pdev->dev, "Root MC bus device removed");
        return 0;
 }
-- 
1.9.0