[Freedreno] [PATCH v2 8/9] drm/fdinfo: Add comm/cmdline override fields

[Rob Clark]

From: Rob Clark <robdcl...@chromium.org>

These are useful in particular for VM scenarios where the process which
has opened to drm device file is just a proxy for the real user in a VM
guest.

Signed-off-by: Rob Clark <robdcl...@chromium.org>
---
 Documentation/gpu/drm-usage-stats.rst | 18 ++++++++++++++++++
 drivers/gpu/drm/drm_file.c            | 15 +++++++++++++++
 include/drm/drm_file.h                | 19 +++++++++++++++++++
 3 files changed, 52 insertions(+)

diff --git a/Documentation/gpu/drm-usage-stats.rst 
b/Documentation/gpu/drm-usage-stats.rst
index 58dc0d3f8c58..e4877cf8089c 100644
--- a/Documentation/gpu/drm-usage-stats.rst
+++ b/Documentation/gpu/drm-usage-stats.rst
@@ -73,6 +73,24 @@ scope of each device, in which case `drm-pdev` shall be 
present as well.
 Userspace should make sure to not double account any usage statistics by using
 the above described criteria in order to associate data to individual clients.
 
+- drm-comm-override: <valstr>
+
+Returns the client executable override string.  Some drivers support letting
+userspace override this in cases where the userspace is simply a "proxy".
+Such as is the case with virglrenderer drm native context, where the host
+process is just forwarding command submission, etc, from guest userspace.
+This allows the proxy to make visible the executable name of the actual
+app in the VM guest.
+
+- drm-cmdline-override: <valstr>
+
+Returns the client cmdline override string.  Some drivers support letting
+userspace override this in cases where the userspace is simply a "proxy".
+Such as is the case with virglrenderer drm native context, where the host
+process is just forwarding command submission, etc, from guest userspace.
+This allows the proxy to make visible the cmdline of the actual app in the
+VM guest.
+
 Utilization
 ^^^^^^^^^^^
 
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 9321eb0bf020..d7514c313af1 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -178,6 +178,8 @@ struct drm_file *drm_file_alloc(struct drm_minor *minor)
        spin_lock_init(&file->master_lookup_lock);
        mutex_init(&file->event_read_lock);
 
+       mutex_init(&file->override_lock);
+
        if (drm_core_check_feature(dev, DRIVER_GEM))
                drm_gem_open(dev, file);
 
@@ -292,6 +294,8 @@ void drm_file_free(struct drm_file *file)
        WARN_ON(!list_empty(&file->event_list));
 
        put_pid(file->pid);
+       kfree(file->override_comm);
+       kfree(file->override_cmdline);
        kfree(file);
 }
 
@@ -995,6 +999,17 @@ void drm_show_fdinfo(struct seq_file *m, struct file *f)
                           PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
        }
 
+       mutex_lock(&file->override_lock);
+       if (file->override_comm) {
+               drm_printf(&p, "drm-comm-override:\t%s\n",
+                          file->override_comm);
+       }
+       if (file->override_cmdline) {
+               drm_printf(&p, "drm-cmdline-override:\t%s\n",
+                          file->override_cmdline);
+       }
+       mutex_unlock(&file->override_lock);
+
        if (dev->driver->show_fdinfo)
                dev->driver->show_fdinfo(&p, file);
 }
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 1339e925af52..604d05fa6f0c 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -370,6 +370,25 @@ struct drm_file {
         */
        struct drm_prime_file_private prime;
 
+       /**
+        * @comm: Overridden task comm
+        *
+        * Accessed under override_lock
+        */
+       char *override_comm;
+
+       /**
+        * @cmdline: Overridden task cmdline
+        *
+        * Accessed under override_lock
+        */
+       char *override_cmdline;
+
+       /**
+        * @override_lock: Serialize access to override_comm and 
override_cmdline
+        */
+       struct mutex override_lock;
+
        /* private: */
 #if IS_ENABLED(CONFIG_DRM_LEGACY)
        unsigned long lock_count; /* DRI1 legacy lock count */
-- 
2.39.2