On 15/04/2025 12:25, Sunil Khatri wrote:
Add helper function which get the process information for
the drm_file and updates the user provided character buffer
with the information of process name and pid as a string.
Signed-off-by: Sunil Khatri <sunil.kha...@amd.com>
---
drivers/gpu/drm/drm_file.c | 34 ++++++++++++++++++++++++++++++++++
include/drm/drm_file.h | 1 +
2 files changed, 35 insertions(+)
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index c299cd94d3f7..728a60975f5e 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -986,6 +986,40 @@ void drm_show_fdinfo(struct seq_file *m, struct file *f)
}
EXPORT_SYMBOL(drm_show_fdinfo);
+/**
+ * drm_process_info - Fill info string with process name and pid
+ * @file_priv: context of interest for process name and pid
+ * @proc_info: user char ptr to write the string to
+ * @buff_size: size of the buffer passed for the string
+ *
+ * This update the user provided buffer with process
+ * name and pid information for @file_priv
+ */
+void drm_process_info(struct drm_file *file_priv, char *proc_info, size_t
buff_size)
+{
+ struct task_struct *task;
+ struct pid *pid;
+ struct drm_device *dev = file_priv->minor->dev;
+
+ if (!proc_info) {
+ drm_WARN_ON_ONCE(dev, "Invalid user buffer\n");
+ return;
+ }
I think this should be:
if (drm_WARN_ON_ONCE(dev, !proc_info))
return;
+
+ mutex_lock(&file_priv->client_name_lock);
+ rcu_read_lock();
+ pid = rcu_dereference(file_priv->pid);
+ task = pid_task(pid, PIDTYPE_TGID);
+ if (task)
+ snprintf(proc_info, buff_size, "client_name:%s proc:%s pid:%d",
+ file_priv->client_name ? file_priv->client_name :
"Unset",
+ task->comm, task->pid);
Probably bad to return uninitialised string for the !task case.
Also, now that you added client name the case to move towards the helper
which does not need a temporary buffer, like I was suggesting
drm_file_err(drm_file *, const char *, ...), is IMO even stronger.
Consider if nothing else DRM_CLIENT_NAME_MAX_LEN plus the length of
other fields you will be adding (the series as is can truncate). And it
would be a bit unsightly to require relatively huge stack buffers in the
later patches when it can all be easily avoided.
Regards,
Tvrtko
+
+ rcu_read_unlock();
+ mutex_unlock(&file_priv->client_name_lock);
+}
+EXPORT_SYMBOL(drm_process_info);
+
/**
* mock_drm_getfile - Create a new struct file for the drm device
* @minor: drm minor to wrap (e.g. #drm_device.primary)
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 94d365b22505..a972be73a615 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -507,6 +507,7 @@ void drm_print_memory_stats(struct drm_printer *p,
void drm_show_memory_stats(struct drm_printer *p, struct drm_file *file);
void drm_show_fdinfo(struct seq_file *m, struct file *f);
+void drm_process_info(struct drm_file *file_priv, char *proc_info, size_t
buff_size);
struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags);
