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

Tvrtko Ursulin
2020-01-10T13:30:58Z

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;
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;

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