Nouveau, in normal circumstances, does not need device lock for every ioctl,
but incoming "gpu reset" code needs exclusive access to the device.
This commit adds drm_driver flag which turns on read lock ioctl encapsulation.
Signed-off-by: Marcin Slusarz <marcin.slusarz@xxxxxxxxx>
---
drivers/gpu/drm/drm_drv.c | 6 ++++++
drivers/gpu/drm/drm_stub.c | 2 ++
include/drm/drmP.h | 4 ++++
3 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 6116e3b..c54e9f8 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -464,6 +464,9 @@ long drm_ioctl(struct file *filp,
} else
memset(kdata, 0, usize);
+ if (dev->driver->ioctls_need_rwsem)
+ down_read(&dev->ioctls_rwsem);
+
if (ioctl->flags & DRM_UNLOCKED)
retcode = func(dev, kdata, file_priv);
else {
@@ -472,6 +475,9 @@ long drm_ioctl(struct file *filp,
mutex_unlock(&drm_global_mutex);
}
+ if (dev->driver->ioctls_need_rwsem)
+ up_read(&dev->ioctls_rwsem);
+
if (cmd & IOC_OUT) {
if (copy_to_user((void __user *)arg, kdata,
usize) != 0)
diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index aa454f8..4af3227 100644
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -275,6 +275,8 @@ int drm_fill_in_dev(struct drm_device *dev,
mutex_init(&dev->struct_mutex);
mutex_init(&dev->ctxlist_mutex);
+ init_rwsem(&dev->ioctls_rwsem);
+
if (drm_ht_create(&dev->map_hash, 12)) {
return -ENOMEM;
}
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index dd73104..527dca5 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -954,6 +954,8 @@ struct drm_driver {
int dev_priv_size;
struct drm_ioctl_desc *ioctls;
int num_ioctls;
+ bool ioctls_need_rwsem;
+
const struct file_operations *fops;
union {
struct pci_driver *pci;
@@ -1070,6 +1072,8 @@ struct drm_device {
/*@{ */
spinlock_t count_lock; /**< For inuse, drm_device::open_count, drm_device::buf_use */
struct mutex struct_mutex; /**< For others */
+
+ struct rw_semaphore ioctls_rwsem;
/*@} */
/** \name Usage Counters */
--
1.7.8.5
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