drm: Protect dev->filelist with its own mutex
amdgpu gained dev->struct_mutex usage, and that's because it's walking
the dev->filelist list. Protect that list with it's own lock to take
one more step towards getting rid of struct_mutex usage in drivers
once and for all.
While doing the conversion I noticed that 2 debugfs files in i915
completely lacked appropriate locking. Fix that up too.
v2: don't forget to switch to drm_gem_object_unreference_unlocked.
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461691808-12414-9-git-send-email-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 8593394..c298312 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -498,6 +498,10 @@
seq_putc(m, '\n');
print_batch_pool_stats(m, dev_priv);
+
+ mutex_unlock(&dev->struct_mutex);
+
+ mutex_lock(&dev->filelist_mutex);
list_for_each_entry_reverse(file, &dev->filelist, lhead) {
struct file_stats stats;
struct task_struct *task;
@@ -518,8 +522,7 @@
print_file_stats(m, task ? task->comm : "<unknown>", stats);
rcu_read_unlock();
}
-
- mutex_unlock(&dev->struct_mutex);
+ mutex_unlock(&dev->filelist_mutex);
return 0;
}
@@ -2325,6 +2328,7 @@
else if (INTEL_INFO(dev)->gen >= 6)
gen6_ppgtt_info(m, dev);
+ mutex_lock(&dev->filelist_mutex);
list_for_each_entry_reverse(file, &dev->filelist, lhead) {
struct drm_i915_file_private *file_priv = file->driver_priv;
struct task_struct *task;
@@ -2339,6 +2343,7 @@
idr_for_each(&file_priv->context_idr, per_file_ctx,
(void *)(unsigned long)m);
}
+ mutex_unlock(&dev->filelist_mutex);
out_put:
intel_runtime_pm_put(dev_priv);
@@ -2374,6 +2379,8 @@
intel_gpu_freq(dev_priv, dev_priv->rps.min_freq_softlimit),
intel_gpu_freq(dev_priv, dev_priv->rps.max_freq_softlimit),
intel_gpu_freq(dev_priv, dev_priv->rps.max_freq));
+
+ mutex_lock(&dev->filelist_mutex);
spin_lock(&dev_priv->rps.client_lock);
list_for_each_entry_reverse(file, &dev->filelist, lhead) {
struct drm_i915_file_private *file_priv = file->driver_priv;
@@ -2396,6 +2403,7 @@
list_empty(&dev_priv->rps.mmioflips.link) ? "" : ", active");
seq_printf(m, "Kernel boosts: %d\n", dev_priv->rps.boosts);
spin_unlock(&dev_priv->rps.client_lock);
+ mutex_unlock(&dev->filelist_mutex);
return 0;
}