drm/msm: show task cmdline in gpu recovery messages

Now that freedreno gallium driver defaults to using submit_queue task
(render reordering), just showing task->comm is not so useful (ie. it is
always "flush_queue:0"), so also dump the cmdline.  This should also be
more useful for piglit/shader_runner.

Signed-off-by: Rob Clark <robdclark@gmail.com>

diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index a05aa119f22b957974ec749215397e20d40a9274..8481014192d14cd3173cb1aa4178ded1a7ba5f48 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -20,6 +20,8 @@
 #include "msm_mmu.h"
 #include "msm_fence.h"
 
+#include <linux/string_helpers.h>
+
 
 /*
  * Power Management:
@@ -235,6 +237,20 @@ static void update_fences(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
        }
 }
 
+static struct msm_gem_submit *
+find_submit(struct msm_ringbuffer *ring, uint32_t fence)
+{
+       struct msm_gem_submit *submit;
+
+       WARN_ON(!mutex_is_locked(&ring->gpu->dev->struct_mutex));
+
+       list_for_each_entry(submit, &ring->submits, node)
+               if (submit->seqno == fence)
+                       return submit;
+
+       return NULL;
+}
+
 static void retire_submits(struct msm_gpu *gpu);
 
 static void recover_worker(struct work_struct *work)
@@ -268,19 +284,34 @@ static void recover_worker(struct work_struct *work)
        dev_err(dev->dev, "%s: hangcheck recover!\n", gpu->name);
        fence = cur_ring->memptrs->fence + 1;
 
-       list_for_each_entry(submit, &cur_ring->submits, node) {
-               if (submit->seqno == fence) {
-                       struct task_struct *task;
-
-                       rcu_read_lock();
-                       task = pid_task(submit->pid, PIDTYPE_PID);
-                       if (task) {
-                               dev_err(dev->dev, "%s: offending task: %s\n",
-                                               gpu->name, task->comm);
-                       }
-                       rcu_read_unlock();
-                       break;
+       submit = find_submit(cur_ring, fence);
+       if (submit) {
+               struct task_struct *task;
+
+               rcu_read_lock();
+               task = pid_task(submit->pid, PIDTYPE_PID);
+               if (task) {
+                       char *cmd;
+
+                       /*
+                        * So slightly annoying, in other paths like
+                        * mmap'ing gem buffers, mmap_sem is acquired
+                        * before struct_mutex, which means we can't
+                        * hold struct_mutex across the call to
+                        * get_cmdline().  But submits are retired
+                        * from the same in-order workqueue, so we can
+                        * safely drop the lock here without worrying
+                        * about the submit going away.
+                        */
+                       mutex_unlock(&dev->struct_mutex);
+                       cmd = kstrdup_quotable_cmdline(task, GFP_KERNEL);
+                       mutex_lock(&dev->struct_mutex);
+
+                       dev_err(dev->dev, "%s: offending task: %s (%s)\n",
+                               gpu->name, task->comm, cmd);
                }
+               rcu_read_unlock();
+
        }
 
        if (msm_gpu_active(gpu)) {