From: Tvrtko Ursulin <[email protected]> Add a helper which allows migrating the tracked client from one process to another.
Signed-off-by: Tvrtko Ursulin <[email protected]> --- drivers/gpu/drm/drm_cgroup.c | 111 ++++++++++++++++++++++++++++++----- include/drm/drm_clients.h | 7 +++ include/drm/drm_file.h | 1 + 3 files changed, 103 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/drm_cgroup.c b/drivers/gpu/drm/drm_cgroup.c index 7ed9c7150cae..59b730ed1334 100644 --- a/drivers/gpu/drm/drm_cgroup.c +++ b/drivers/gpu/drm/drm_cgroup.c @@ -8,9 +8,21 @@ static DEFINE_XARRAY(drm_pid_clients); +static void +__del_clients(struct drm_pid_clients *clients, struct drm_file *file_priv) +{ + list_del_rcu(&file_priv->clink); + if (atomic_dec_and_test(&clients->num)) { + xa_erase(&drm_pid_clients, (unsigned long)file_priv->cpid); + kfree_rcu(clients, rcu); + } + + put_pid(file_priv->cpid); + file_priv->cpid = NULL; +} + void drm_clients_close(struct drm_file *file_priv) { - unsigned long pid = (unsigned long)file_priv->pid; struct drm_device *dev = file_priv->minor->dev; struct drm_pid_clients *clients; @@ -19,19 +31,32 @@ void drm_clients_close(struct drm_file *file_priv) if (!dev->driver->cg_ops) return; - clients = xa_load(&drm_pid_clients, pid); - list_del_rcu(&file_priv->clink); - if (atomic_dec_and_test(&clients->num)) { - xa_erase(&drm_pid_clients, pid); - kfree_rcu(clients, rcu); + clients = xa_load(&drm_pid_clients, (unsigned long)file_priv->cpid); + if (WARN_ON_ONCE(!clients)) + return; - /* - * FIXME: file_priv is not RCU protected so we add this hack - * to avoid any races with code which walks clients->file_list - * and accesses file_priv. - */ - synchronize_rcu(); + __del_clients(clients, file_priv); + + /* + * FIXME: file_priv is not RCU protected so we add this hack + * to avoid any races with code which walks clients->file_list + * and accesses file_priv. + */ + synchronize_rcu(); +} + +static struct drm_pid_clients *__alloc_clients(void) +{ + struct drm_pid_clients *clients; + + clients = kmalloc(sizeof(*clients), GFP_KERNEL); + if (clients) { + atomic_set(&clients->num, 0); + INIT_LIST_HEAD(&clients->file_list); + init_rcu_head(&clients->rcu); } + + return clients; } int drm_clients_open(struct drm_file *file_priv) @@ -48,12 +73,9 @@ int drm_clients_open(struct drm_file *file_priv) clients = xa_load(&drm_pid_clients, pid); if (!clients) { - clients = kmalloc(sizeof(*clients), GFP_KERNEL); + clients = __alloc_clients(); if (!clients) return -ENOMEM; - atomic_set(&clients->num, 0); - INIT_LIST_HEAD(&clients->file_list); - init_rcu_head(&clients->rcu); new_client = true; } atomic_inc(&clients->num); @@ -69,9 +91,66 @@ int drm_clients_open(struct drm_file *file_priv) } } + file_priv->cpid = get_pid(file_priv->pid); + return 0; } +void drm_clients_migrate(struct drm_file *file_priv) +{ + struct drm_device *dev = file_priv->minor->dev; + struct drm_pid_clients *existing_clients; + struct drm_pid_clients *clients, *spare; + struct pid *pid = task_pid(current); + + if (!dev->driver->cg_ops) + return; + + // TODO: only do this if drmcs level property allows it? + + spare = __alloc_clients(); + if (WARN_ON(!spare)) + return; + + mutex_lock(&dev->filelist_mutex); + rcu_read_lock(); + + existing_clients = xa_load(&drm_pid_clients, (unsigned long)pid); + clients = xa_load(&drm_pid_clients, (unsigned long)file_priv->cpid); + + if (WARN_ON_ONCE(!clients)) + goto out_unlock; + else if (clients == existing_clients) + goto out_unlock; + + __del_clients(clients, file_priv); + smp_mb(); /* hmmm? del_rcu followed by add_rcu? */ + + if (!existing_clients) { + void *xret; + + xret = xa_store(&drm_pid_clients, (unsigned long)pid, spare, + GFP_KERNEL); + if (WARN_ON(xa_err(xret))) + goto out_unlock; + clients = spare; + spare = NULL; + } else { + clients = existing_clients; + } + + atomic_inc(&clients->num); + list_add_tail_rcu(&file_priv->clink, &clients->file_list); + file_priv->cpid = get_pid(pid); + +out_unlock: + rcu_read_unlock(); + mutex_unlock(&dev->filelist_mutex); + + kfree(spare); +} +EXPORT_SYMBOL_GPL(drm_clients_migrate); + unsigned int drm_pid_priority_levels(struct pid *pid, bool *non_uniform) { unsigned int min_levels = UINT_MAX; diff --git a/include/drm/drm_clients.h b/include/drm/drm_clients.h index 10d21138f7af..3a0b1cdb338f 100644 --- a/include/drm/drm_clients.h +++ b/include/drm/drm_clients.h @@ -17,6 +17,8 @@ struct drm_pid_clients { #if IS_ENABLED(CONFIG_CGROUP_DRM) void drm_clients_close(struct drm_file *file_priv); int drm_clients_open(struct drm_file *file_priv); + +void drm_clients_migrate(struct drm_file *file_priv); #else static inline void drm_clients_close(struct drm_file *file_priv) { @@ -26,6 +28,11 @@ static inline int drm_clients_open(struct drm_file *file_priv) { return 0; } + +static inline void drm_clients_migrate(struct drm_file *file_priv) +{ + +} #endif unsigned int drm_pid_priority_levels(struct pid *pid, bool *non_uniform); diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h index a4360e28e2db..2c1e356d3b73 100644 --- a/include/drm/drm_file.h +++ b/include/drm/drm_file.h @@ -280,6 +280,7 @@ struct drm_file { #if IS_ENABLED(CONFIG_CGROUP_DRM) struct list_head clink; + struct pid *cpid; #endif /** -- 2.34.1
