Re: [Intel-gfx] [RFC 2/8] drm/i915: Update client name on context create

Chris Wilson
2020-01-10T13:40:02Z

Quoting Tvrtko Ursulin (2020-01-10 13:30:43)
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>
> Some clients have the DRM fd passed to them over a socket by the X server.
>
> Grab the real client and pid when they create their first context and
> update the exposed data for more useful enumeration.
>
> v2:
> * Do not leak the pid reference and borrow context idr_lock. (Chris)
>
> v3:
> * More avoiding leaks. (Chris)
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_context.c | 36 ++++++++++++++++++---
> drivers/gpu/drm/i915/i915_drm_client.c | 4 +--
> drivers/gpu/drm/i915/i915_drm_client.h | 4 +++
> 3 files changed, 37 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index a2e57e62af30..ba3c29a01535 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -77,6 +77,7 @@
> #include "gt/intel_lrc_reg.h"
> #include "gt/intel_ring.h"
>
> +#include "i915_drm_client.h"
> #include "i915_gem_context.h"
> #include "i915_globals.h"
> #include "i915_trace.h"
> @@ -2181,7 +2182,10 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
> {
> struct drm_i915_private *i915 = to_i915(dev);
> struct drm_i915_gem_context_create_ext *args = data;
> + struct drm_i915_file_private *file_priv = file->driver_priv;
> + struct i915_drm_client *client = file_priv->client;
> struct create_ext ext_data;
> + struct pid *pid;
> int ret;
> u32 id;
>
> @@ -2195,16 +2199,35 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
> if (ret)
> return ret;
>
> - ext_data.fpriv = file->driver_priv;
> + pid = get_task_pid(current, PIDTYPE_PID);
> +
> + ext_data.fpriv = file_priv;

Might as well do this in the declaration ?

struct create_ext ext_data {
.fpriv = file->driver_priv,
};
struct i915_drm_client *client = ext_data.fpriv->client;

?

> if (client_is_banned(ext_data.fpriv)) {
> DRM_DEBUG("client %s[%d] banned from creating ctx\n",
> - current->comm, task_pid_nr(current));
> - return -EIO;
> + current->comm, pid_nr(pid));
> + ret = -EIO;
> + goto err_pid;
> + }
> +
> + /*
> + * Borrow struct_mutex to protect the client remove-add cycle.
> + */
> + ret = mutex_lock_interruptible(&dev->struct_mutex);
> + if (ret)
> + goto err_pid;
> + if (client->pid != pid) {
> + __i915_drm_client_unregister(client);
> + ret = __i915_drm_client_register(client, current);
> }
> + mutex_unlock(&dev->struct_mutex);
> + if (ret)
> + goto err_pid;

-> i915_drm_client_update();

And let it manage the pid locally?

>
> ext_data.ctx = i915_gem_create_context(i915, args->flags);
> - if (IS_ERR(ext_data.ctx))
> - return PTR_ERR(ext_data.ctx);
> + if (IS_ERR(ext_data.ctx)) {
> + ret = PTR_ERR(ext_data.ctx);
> + goto err_pid;
> + }
>
> if (args->flags & I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS) {
> ret = i915_user_extensions(u64_to_user_ptr(args->extensions),
> @@ -2226,6 +2249,9 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
>
> err_ctx:
> context_close(ext_data.ctx);
> +err_pid:
> + put_pid(pid);
> +
> return ret;
> }
>
> diff --git a/drivers/gpu/drm/i915/i915_drm_client.c b/drivers/gpu/drm/i915/i915_drm_client.c
> index 02356f48d85b..666ec67c77e9 100644
> --- a/drivers/gpu/drm/i915/i915_drm_client.c
> +++ b/drivers/gpu/drm/i915/i915_drm_client.c
> @@ -36,7 +36,7 @@ show_client_pid(struct device *kdev, struct device_attribute *attr, char *buf)
> client->closed ? ">" : "");
> }
>
> -static int
> +int
> __i915_drm_client_register(struct i915_drm_client *client,
> struct task_struct *task)
> {
> @@ -89,7 +89,7 @@ __i915_drm_client_register(struct i915_drm_client *client,
> return ret;
> }
>
> -static void __i915_drm_client_unregister(struct i915_drm_client *client)
> +void __i915_drm_client_unregister(struct i915_drm_client *client)
> {
> if (!client->name)
> return; /* fbdev client or error during drm open */
> diff --git a/drivers/gpu/drm/i915/i915_drm_client.h b/drivers/gpu/drm/i915/i915_drm_client.h
> index 8b261dc4a1f3..2c692345bc4e 100644
> --- a/drivers/gpu/drm/i915/i915_drm_client.h
> +++ b/drivers/gpu/drm/i915/i915_drm_client.h
> @@ -58,4 +58,8 @@ void i915_drm_client_close(struct i915_drm_client *client);
> struct i915_drm_client *i915_drm_client_add(struct i915_drm_clients *clients,
> struct task_struct *task);
>
> +int __i915_drm_client_register(struct i915_drm_client *client,
> + struct task_struct *task);
> +void __i915_drm_client_unregister(struct i915_drm_client *client);
> +
> #endif /* !__I915_DRM_CLIENT_H__ */
> --
> 2.20.1
>
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