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Subject[PATCH 6/9] vfio/fsl-mc: Added lock support in preparation for interrupt handling
Date
From: Diana Craciun <diana.craciun@nxp.com>

Only the DPRC object allocates interrupts from the MSI
interrupt domain. The interrupts are managed by the DPRC in
a pool of interrupts. The access to this pool of interrupts
has to be protected with a lock.
This patch extends the current lock implementation to have a
lock per DPRC.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
---
drivers/vfio/fsl-mc/vfio_fsl_mc.c | 90 +++++++++++++++++++++--
drivers/vfio/fsl-mc/vfio_fsl_mc_private.h | 7 +-
2 files changed, 90 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
index 6625b7cb0a3e..ea5e81e7791c 100644
--- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
+++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
@@ -15,6 +15,76 @@

#include "vfio_fsl_mc_private.h"

+static DEFINE_MUTEX(reflck_lock);
+
+static void vfio_fsl_mc_reflck_get(struct vfio_fsl_mc_reflck *reflck)
+{
+ kref_get(&reflck->kref);
+}
+
+static void vfio_fsl_mc_reflck_release(struct kref *kref)
+{
+ struct vfio_fsl_mc_reflck *reflck = container_of(kref,
+ struct vfio_fsl_mc_reflck,
+ kref);
+
+ kfree(reflck);
+ mutex_unlock(&reflck_lock);
+}
+
+static void vfio_fsl_mc_reflck_put(struct vfio_fsl_mc_reflck *reflck)
+{
+ kref_put_mutex(&reflck->kref, vfio_fsl_mc_reflck_release, &reflck_lock);
+}
+
+static struct vfio_fsl_mc_reflck *vfio_fsl_mc_reflck_alloc(void)
+{
+ struct vfio_fsl_mc_reflck *reflck;
+
+ reflck = kzalloc(sizeof(*reflck), GFP_KERNEL);
+ if (!reflck)
+ return ERR_PTR(-ENOMEM);
+
+ kref_init(&reflck->kref);
+ mutex_init(&reflck->lock);
+
+ return reflck;
+}
+
+static int vfio_fsl_mc_reflck_attach(struct vfio_fsl_mc_device *vdev)
+{
+ int ret = 0;
+
+ mutex_lock(&reflck_lock);
+ if (is_fsl_mc_bus_dprc(vdev->mc_dev)) {
+ vdev->reflck = vfio_fsl_mc_reflck_alloc();
+ } else {
+ struct device *mc_cont_dev = vdev->mc_dev->dev.parent;
+ struct vfio_device *device;
+ struct vfio_fsl_mc_device *cont_vdev;
+
+ device = vfio_device_get_from_dev(mc_cont_dev);
+ if (!device) {
+ ret = -ENODEV;
+ goto unlock;
+ }
+
+ cont_vdev = vfio_device_data(device);
+ if (!cont_vdev->reflck) {
+ vfio_device_put(device);
+ ret = -ENODEV;
+ goto unlock;
+ }
+ vfio_fsl_mc_reflck_get(cont_vdev->reflck);
+ vdev->reflck = cont_vdev->reflck;
+ vfio_device_put(device);
+ }
+
+unlock:
+ mutex_unlock(&reflck_lock);
+ return ret;
+}
+
static int vfio_fsl_mc_regions_init(struct vfio_fsl_mc_device *vdev)
{
struct fsl_mc_device *mc_dev = vdev->mc_dev;
@@ -56,7 +126,7 @@ static int vfio_fsl_mc_open(void *device_data)
if (!try_module_get(THIS_MODULE))
return -ENODEV;

- mutex_lock(&vdev->driver_lock);
+ mutex_lock(&vdev->reflck->lock);
if (!vdev->refcnt) {
ret = vfio_fsl_mc_regions_init(vdev);
if (ret)
@@ -64,11 +134,11 @@ static int vfio_fsl_mc_open(void *device_data)
}
vdev->refcnt++;

- mutex_unlock(&vdev->driver_lock);
+ mutex_unlock(&vdev->reflck->lock);
return 0;

err_reg_init:
- mutex_unlock(&vdev->driver_lock);
+ mutex_unlock(&vdev->reflck->lock);
module_put(THIS_MODULE);
return ret;
}
@@ -77,12 +147,12 @@ static void vfio_fsl_mc_release(void *device_data)
{
struct vfio_fsl_mc_device *vdev = device_data;

- mutex_lock(&vdev->driver_lock);
+ mutex_lock(&vdev->reflck->lock);

if (!(--vdev->refcnt))
vfio_fsl_mc_regions_cleanup(vdev);

- mutex_unlock(&vdev->driver_lock);
+ mutex_unlock(&vdev->reflck->lock);

module_put(THIS_MODULE);
}
@@ -294,12 +364,18 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
return ret;
}

+ ret = vfio_fsl_mc_reflck_attach(vdev);
+ if (ret) {
+ vfio_iommu_group_put(group, dev);
+ return ret;
+ }
+
ret = vfio_fsl_mc_init_device(vdev);
if (ret) {
+ vfio_fsl_mc_reflck_put(vdev->reflck);
vfio_iommu_group_put(group, dev);
return ret;
}
- mutex_init(&vdev->driver_lock);

return ret;
}
@@ -340,6 +416,8 @@ static int vfio_fsl_mc_remove(struct fsl_mc_device *mc_dev)
if (!vdev)
return -EINVAL;

+ vfio_fsl_mc_reflck_put(vdev->reflck);
+
if (is_fsl_mc_bus_dprc(mc_dev))
vfio_fsl_mc_cleanup_dprc(vdev->mc_dev);

diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h b/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
index e2a0ccdd8242..d072cccd93e0 100644
--- a/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
+++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
@@ -17,6 +17,11 @@

#define VFIO_DPRC_REGION_CACHEABLE 0x00000001

+struct vfio_fsl_mc_reflck {
+ struct kref kref;
+ struct mutex lock;
+};
+
struct vfio_fsl_mc_region {
u32 flags;
u32 type;
@@ -29,7 +34,7 @@ struct vfio_fsl_mc_device {
int refcnt;
u32 num_regions;
struct vfio_fsl_mc_region *regions;
- struct mutex driver_lock;
+ struct vfio_fsl_mc_reflck *reflck;
};

#endif /* VFIO_PCI_PRIVATE_H */
--
2.17.1
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