target/linux/layerscape/patches-4.4/7185-staging-fsl-mc-fix-asymmetry-in-destroy-of-mc_io.patch

   1 From 4e55a4c296d3a93c95320cdac0b8e72f3cfefb98 Mon Sep 17 00:00:00 2001
   2 From: Bharat Bhushan <Bharat.Bhushan@nxp.com>
   3 Date: Wed, 22 Jun 2016 16:40:48 -0500
   4 Subject: [PATCH 185/226] staging: fsl-mc: fix asymmetry in destroy of mc_io
   5
   6 An mc_io represents a mapped MC portal.  Previously, an mc_io was
   7 created for the root dprc in fsl_mc_bus_probe() and for child dprcs
   8 in dprc_probe().  But the free of that data structure happened in the
   9 general bus remove callback.  This asymmetry resulted in some bugs due
  10 to unwanted destroys of mc_io object in some scenarios (e.g. vfio).
  11
  12 Fix this bug by making things symmetric-- mc_io created in
  13 fsl_mc_bus_probe() is freed in fsl_mc_bus_remove().  The mc_io created
  14 in dprc_probe() is freed in dprc_remove().
  15
  16 Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
  17 [Stuart: added check for root dprc and reworded commit message]
  18 Signed-off-by: Stuart Yoder <stuart.yoder@nxp.com>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  20 ---
  21  drivers/staging/fsl-mc/bus/dprc-driver.c |    5 +++++
  22  drivers/staging/fsl-mc/bus/mc-bus.c      |    8 ++++----
  23  2 files changed, 9 insertions(+), 4 deletions(-)
  24
  25 --- a/drivers/staging/fsl-mc/bus/dprc-driver.c
  26 +++ b/drivers/staging/fsl-mc/bus/dprc-driver.c
  27 @@ -801,6 +801,11 @@ static int dprc_remove(struct fsl_mc_dev
  28                 dev_set_msi_domain(&mc_dev->dev, NULL);
  29         }
  30
  31 +       if (!fsl_mc_is_root_dprc(&mc_dev->dev)) {
  32 +               fsl_destroy_mc_io(mc_dev->mc_io);
  33 +               mc_dev->mc_io = NULL;
  34 +       }
  35 +
  36         dev_info(&mc_dev->dev, "DPRC device unbound from driver");
  37         return 0;
  38  }
  39 --- a/drivers/staging/fsl-mc/bus/mc-bus.c
  40 +++ b/drivers/staging/fsl-mc/bus/mc-bus.c
  41 @@ -579,10 +579,6 @@ void fsl_mc_device_remove(struct fsl_mc_
  42
  43         if (strcmp(mc_dev->obj_desc.type, "dprc") == 0) {
  44                 mc_bus = to_fsl_mc_bus(mc_dev);
  45 -               if (mc_dev->mc_io) {
  46 -                       fsl_destroy_mc_io(mc_dev->mc_io);
  47 -                       mc_dev->mc_io = NULL;
  48 -               }
  49
  50                 if (fsl_mc_is_root_dprc(&mc_dev->dev)) {
  51                         if (atomic_read(&root_dprc_count) > 0)
  52 @@ -810,6 +806,10 @@ static int fsl_mc_bus_remove(struct plat
  53                 return -EINVAL;
  54
  55         fsl_mc_device_remove(mc->root_mc_bus_dev);
  56 +
  57 +       fsl_destroy_mc_io(mc->root_mc_bus_dev->mc_io);
  58 +       mc->root_mc_bus_dev->mc_io = NULL;
  59 +
  60         dev_info(&pdev->dev, "Root MC bus device removed");
  61         return 0;
  62  }