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/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index fa6a27b..a087b96 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -93,7 +93,7 @@ void amdgpu_gem_force_release(struct amdgpu_device *adev)
        struct drm_device *ddev = adev->ddev;
        struct drm_file *file;
 
-       mutex_lock(&ddev->struct_mutex);
+       mutex_lock(&ddev->filelist_mutex);
 
        list_for_each_entry(file, &ddev->filelist, lhead) {
                struct drm_gem_object *gobj;
@@ -103,13 +103,13 @@ void amdgpu_gem_force_release(struct amdgpu_device *adev)
                spin_lock(&file->table_lock);
                idr_for_each_entry(&file->object_idr, gobj, handle) {
                        WARN_ONCE(1, "And also active allocations!\n");
-                       drm_gem_object_unreference(gobj);
+                       drm_gem_object_unreference_unlocked(gobj);
                }
                idr_destroy(&file->object_idr);
                spin_unlock(&file->table_lock);
        }
 
-       mutex_unlock(&ddev->struct_mutex);
+       mutex_unlock(&ddev->filelist_mutex);
 }
 
 /*
@@ -769,7 +769,7 @@ static int amdgpu_debugfs_gem_info(struct seq_file *m, void *data)
        struct drm_file *file;
        int r;
 
-       r = mutex_lock_interruptible(&dev->struct_mutex);
+       r = mutex_lock_interruptible(&dev->filelist_mutex);
        if (r)
                return r;
 
@@ -793,7 +793,7 @@ static int amdgpu_debugfs_gem_info(struct seq_file *m, void *data)
                spin_unlock(&file->table_lock);
        }
 
-       mutex_unlock(&dev->struct_mutex);
+       mutex_unlock(&dev->filelist_mutex);
        return 0;
 }
 

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index e1fb52d..bff8922 100644 (file)
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -590,6 +590,7 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver,
        spin_lock_init(&dev->buf_lock);
        spin_lock_init(&dev->event_lock);
        mutex_init(&dev->struct_mutex);
+       mutex_init(&dev->filelist_mutex);
        mutex_init(&dev->ctxlist_mutex);
        mutex_init(&dev->master_mutex);
 

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index c3d0aaa..7af7f8b 100644 (file)
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -297,9 +297,9 @@ static int drm_open_helper(struct file *filp, struct drm_minor *minor)
        }
        mutex_unlock(&dev->master_mutex);
 
-       mutex_lock(&dev->struct_mutex);
+       mutex_lock(&dev->filelist_mutex);
        list_add(&priv->lhead, &dev->filelist);
-       mutex_unlock(&dev->struct_mutex);
+       mutex_unlock(&dev->filelist_mutex);
 
 #ifdef __alpha__
        /*
@@ -447,8 +447,11 @@ int drm_release(struct inode *inode, struct file *filp)
 
        DRM_DEBUG("open_count = %d\n", dev->open_count);
 
-       mutex_lock(&dev->struct_mutex);
+       mutex_lock(&dev->filelist_mutex);
        list_del(&file_priv->lhead);
+       mutex_unlock(&dev->filelist_mutex);
+
+       mutex_lock(&dev->struct_mutex);
        if (file_priv->magic)
                idr_remove(&file_priv->master->magic_map, file_priv->magic);
        mutex_unlock(&dev->struct_mutex);

diff --git a/drivers/gpu/drm/drm_info.c b/drivers/gpu/drm/drm_info.c
index cbb4fc0..5d469b2 100644 (file)
--- a/drivers/gpu/drm/drm_info.c
+++ b/drivers/gpu/drm/drm_info.c
@@ -174,7 +174,7 @@ int drm_clients_info(struct seq_file *m, void *data)
        /* dev->filelist is sorted youngest first, but we want to present
         * oldest first (i.e. kernel, servers, clients), so walk backwardss.
         */
-       mutex_lock(&dev->struct_mutex);
+       mutex_lock(&dev->filelist_mutex);
        list_for_each_entry_reverse(priv, &dev->filelist, lhead) {
                struct task_struct *task;
 
@@ -190,7 +190,7 @@ int drm_clients_info(struct seq_file *m, void *data)
                           priv->magic);
                rcu_read_unlock();
        }
-       mutex_unlock(&dev->struct_mutex);
+       mutex_unlock(&dev->filelist_mutex);
        return 0;
 }
 

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 8593394..c298312 100644 (file)
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -498,6 +498,10 @@ static int i915_gem_object_info(struct seq_file *m, void* data)
 
        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 @@ static int i915_gem_object_info(struct seq_file *m, void* data)
                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 @@ static int i915_ppgtt_info(struct seq_file *m, void *data)
        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 @@ static int i915_ppgtt_info(struct seq_file *m, void *data)
                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 @@ static int i915_rps_boost_info(struct seq_file *m, void *data)
                   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 @@ static int i915_rps_boost_info(struct seq_file *m, void *data)
                   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;
 }

diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 5de4cff..7901768 100644 (file)
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -769,6 +769,7 @@ struct drm_device {
        atomic_t buf_alloc;             /**< Buffer allocation in progress */
        /*@} */
 
+       struct mutex filelist_mutex;
        struct list_head filelist;
 
        /** \name Memory management */