drm/i915: Kill the active list spinlock

This spinlock only served debugging purposes in a time when we could not
be sure of the mutex ever being released upon a GPU hang. As we now
should be able rely on hangcheck to do the job for us (and that error
reporting should not itself require the struct mutex) we can kill the
incomplete attempt at protection.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 63 insertions, 26 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 16133f10ffaa..9074300fed8d 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -72,12 +72,15 @@ static int i915_gem_object_list_info(struct seq_file *m, void *data)
 	struct drm_device *dev = node->minor->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj_priv;
-	spinlock_t *lock = NULL;
+	int ret;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
 
 	switch (list) {
 	case ACTIVE_LIST:
 		seq_printf(m, "Active:\n");
-		lock = &dev_priv->mm.active_list_lock;
 		head = &dev_priv->render_ring.active_list;
 		break;
 	case INACTIVE_LIST:
@@ -89,14 +92,11 @@ static int i915_gem_object_list_info(struct seq_file *m, void *data)
 		head = &dev_priv->mm.flushing_list;
 		break;
 	default:
-		DRM_INFO("Ooops, unexpected list\n");
-		return 0;
+		mutex_unlock(&dev->struct_mutex);
+		return -EINVAL;
 	}
 
-	if (lock)
-		spin_lock(lock);
-	list_for_each_entry(obj_priv, head, list)
-	{
+	list_for_each_entry(obj_priv, head, list) {
 		seq_printf(m, "    %p: %s %8zd %08x %08x %d%s%s",
 			   &obj_priv->base,
 			   get_pin_flag(obj_priv),
@@ -117,8 +117,7 @@ static int i915_gem_object_list_info(struct seq_file *m, void *data)
 		seq_printf(m, "\n");
 	}
 
-	if (lock)
-	    spin_unlock(lock);
+	mutex_unlock(&dev->struct_mutex);
 	return 0;
 }
 
@@ -176,6 +175,11 @@ static int i915_gem_request_info(struct seq_file *m, void *data)
 	struct drm_device *dev = node->minor->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_i915_gem_request *gem_request;
+	int ret;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
 
 	seq_printf(m, "Request:\n");
 	list_for_each_entry(gem_request, &dev_priv->render_ring.request_list,
@@ -184,6 +188,8 @@ static int i915_gem_request_info(struct seq_file *m, void *data)
 			   gem_request->seqno,
 			   (int) (jiffies - gem_request->emitted_jiffies));
 	}
+	mutex_unlock(&dev->struct_mutex);
+
 	return 0;
 }
 
@@ -192,6 +198,11 @@ static int i915_gem_seqno_info(struct seq_file *m, void *data)
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
+	int ret;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
 
 	if (dev_priv->render_ring.status_page.page_addr != NULL) {
 		seq_printf(m, "Current sequence: %d\n",
@@ -202,6 +213,9 @@ static int i915_gem_seqno_info(struct seq_file *m, void *data)
 	seq_printf(m, "Waiter sequence:  %d\n",
 			dev_priv->mm.waiting_gem_seqno);
 	seq_printf(m, "IRQ sequence:     %d\n", dev_priv->mm.irq_gem_seqno);
+
+	mutex_unlock(&dev->struct_mutex);
+
 	return 0;
 }
 
@@ -211,6 +225,11 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
+	int ret;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
 
 	if (!HAS_PCH_SPLIT(dev)) {
 		seq_printf(m, "Interrupt enable:    %08x\n",
@@ -255,6 +274,8 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
 		   dev_priv->mm.waiting_gem_seqno);
 	seq_printf(m, "IRQ sequence:        %d\n",
 		   dev_priv->mm.irq_gem_seqno);
+	mutex_unlock(&dev->struct_mutex);
+
 	return 0;
 }
 
@@ -263,7 +284,11 @@ static int i915_gem_fence_regs_info(struct seq_file *m, void *data)
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
-	int i;
+	int i, ret;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
 
 	seq_printf(m, "Reserved fences = %d\n", dev_priv->fence_reg_start);
 	seq_printf(m, "Total fences = %d\n", dev_priv->num_fence_regs);
@@ -289,6 +314,7 @@ static int i915_gem_fence_regs_info(struct seq_file *m, void *data)
 			seq_printf(m, "\n");
 		}
 	}
+	mutex_unlock(&dev->struct_mutex);
 
 	return 0;
 }
@@ -319,10 +345,10 @@ static void i915_dump_pages(struct seq_file *m, struct page **pages, int page_co
 	uint32_t *mem;
 
 	for (page = 0; page < page_count; page++) {
-		mem = kmap_atomic(pages[page], KM_USER0);
+		mem = kmap(pages[page]);
 		for (i = 0; i < PAGE_SIZE; i += 4)
 			seq_printf(m, "%08x :  %08x\n", i, mem[i / 4]);
-		kunmap_atomic(mem, KM_USER0);
+		kunmap(pages[page]);
 	}
 }
 
@@ -335,7 +361,9 @@ static int i915_batchbuffer_info(struct seq_file *m, void *data)
 	struct drm_i915_gem_object *obj_priv;
 	int ret;
 
-	spin_lock(&dev_priv->mm.active_list_lock);
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
 
 	list_for_each_entry(obj_priv, &dev_priv->render_ring.active_list,
 			list) {
@@ -343,8 +371,7 @@ static int i915_batchbuffer_info(struct seq_file *m, void *data)
 		if (obj->read_domains & I915_GEM_DOMAIN_COMMAND) {
 		    ret = i915_gem_object_get_pages(obj, 0);
 		    if (ret) {
-			    DRM_ERROR("Failed to get pages: %d\n", ret);
-			    spin_unlock(&dev_priv->mm.active_list_lock);
+			    mutex_unlock(&dev->struct_mutex);
 			    return ret;
 		    }
 
@@ -355,7 +382,7 @@ static int i915_batchbuffer_info(struct seq_file *m, void *data)
 		}
 	}
 
-	spin_unlock(&dev_priv->mm.active_list_lock);
+	mutex_unlock(&dev->struct_mutex);
 
 	return 0;
 }
@@ -365,20 +392,24 @@ static int i915_ringbuffer_data(struct seq_file *m, void *data)
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
-	u8 *virt;
-	uint32_t *ptr, off;
+	int ret;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
 
 	if (!dev_priv->render_ring.gem_object) {
 		seq_printf(m, "No ringbuffer setup\n");
-		return 0;
-	}
-
-	virt = dev_priv->render_ring.virtual_start;
+	} else {
+		u8 *virt = dev_priv->render_ring.virtual_start;
+		uint32_t off;
 
-	for (off = 0; off < dev_priv->render_ring.size; off += 4) {
-		ptr = (uint32_t *)(virt + off);
-		seq_printf(m, "%08x :  %08x\n", off, *ptr);
+		for (off = 0; off < dev_priv->render_ring.size; off += 4) {
+			uint32_t *ptr = (uint32_t *)(virt + off);
+			seq_printf(m, "%08x :  %08x\n", off, *ptr);
+		}
 	}
+	mutex_unlock(&dev->struct_mutex);
 
 	return 0;
 }
@@ -694,10 +725,16 @@ static int i915_emon_status(struct seq_file *m, void *unused)
 	struct drm_device *dev = node->minor->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	unsigned long temp, chipset, gfx;
+	int ret;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
 
 	temp = i915_mch_val(dev_priv);
 	chipset = i915_chipset_val(dev_priv);
 	gfx = i915_gfx_val(dev_priv);
+	mutex_unlock(&dev->struct_mutex);
 
 	seq_printf(m, "GMCH temp: %ld\n", temp);
 	seq_printf(m, "Chipset power: %ld\n", chipset);