We should never call drm_pci_alloc() while holding locks, due the the

calls to bus_dma.  There were multiple paths that held different locks or
no locks at all. This patch ensures that all of the calling paths drop
their lock(s) before calling drm_pci_alloc().

Reviewed by:	kib

5 files changed, 36 insertions, 14 deletions

diff --git a/sys/dev/drm/ati_pcigart.c b/sys/dev/drm/ati_pcigart.c
index dac400d..597479c 100644
--- a/sys/dev/drm/ati_pcigart.c
+++ b/sys/dev/drm/ati_pcigart.c
@@ -45,12 +45,17 @@ __FBSDID("$FreeBSD$");
 static int drm_ati_alloc_pcigart_table(struct drm_device *dev,
 				       struct drm_ati_pcigart_info *gart_info)
 {
-	dev->sg->dmah = drm_pci_alloc(dev, gart_info->table_size,
-						PAGE_SIZE,
-						gart_info->table_mask);
-	if (dev->sg->dmah == NULL)
+	drm_dma_handle_t *dmah;
+
+	DRM_UNLOCK();
+	dmah = drm_pci_alloc(dev, gart_info->table_size, PAGE_SIZE,
+	    gart_info->table_mask);
+	DRM_LOCK();
+	if (dmah == NULL)
 		return ENOMEM;
 
+	dev->sg->dmah = dmah;
+
 	return 0;
 }
 
diff --git a/sys/dev/drm/drm_bufs.c b/sys/dev/drm/drm_bufs.c
index 9ad13d7..b07359c 100644
--- a/sys/dev/drm/drm_bufs.c
+++ b/sys/dev/drm/drm_bufs.c
@@ -598,8 +598,10 @@ static int drm_do_addbufs_pci(struct drm_device *dev, drm_buf_desc_t *request)
 	page_count = 0;
 
 	while ( entry->buf_count < count ) {
+		DRM_SPINUNLOCK(&dev->dma_lock);
 		drm_dma_handle_t *dmah = drm_pci_alloc(dev, size, alignment,
 		    0xfffffffful);
+		DRM_SPINLOCK(&dev->dma_lock);
 		if (dmah == NULL) {
 			/* Set count correctly so we free the proper amount. */
 			entry->buf_count = count;
diff --git a/sys/dev/drm/drm_pci.c b/sys/dev/drm/drm_pci.c
index a6ddfdf..4aa6d03 100644
--- a/sys/dev/drm/drm_pci.c
+++ b/sys/dev/drm/drm_pci.c
@@ -74,7 +74,12 @@ drm_pci_alloc(struct drm_device *dev, size_t size,
 		return NULL;
 
 #ifdef __FreeBSD__
-	DRM_UNLOCK();
+	/* Make sure we aren't holding locks here */
+	if (mtx_owned(&dev->dev_lock))
+	    DRM_ERROR("called while holding dev_lock\n");
+	if (mtx_owned(&dev->dma_lock))
+	    DRM_ERROR("called while holding dma_lock\n");
+
 	ret = bus_dma_tag_create(NULL, align, 0, /* tag, align, boundary */
 	    maxaddr, BUS_SPACE_MAXADDR, /* lowaddr, highaddr */
 	    NULL, NULL, /* filtfunc, filtfuncargs */
@@ -83,7 +88,6 @@ drm_pci_alloc(struct drm_device *dev, size_t size,
 	    &dmah->tag);
 	if (ret != 0) {
 		free(dmah, M_DRM);
-		DRM_LOCK();
 		return NULL;
 	}
 
@@ -92,10 +96,9 @@ drm_pci_alloc(struct drm_device *dev, size_t size,
 	if (ret != 0) {
 		bus_dma_tag_destroy(dmah->tag);
 		free(dmah, M_DRM);
-		DRM_LOCK();
 		return NULL;
 	}
-	DRM_LOCK();
+
 	ret = bus_dmamap_load(dmah->tag, dmah->map, dmah->vaddr, size,
 	    drm_pci_busdma_callback, dmah, 0);
 	if (ret != 0) {
diff --git a/sys/dev/drm/i915_dma.c b/sys/dev/drm/i915_dma.c
index 8cfdfb0..79e687e 100644
--- a/sys/dev/drm/i915_dma.c
+++ b/sys/dev/drm/i915_dma.c
@@ -250,16 +250,22 @@ static int i915_initialize(struct drm_device * dev,
 
 	/* Program Hardware Status Page */
 	if (!I915_NEED_GFX_HWS(dev)) {
-		dev_priv->status_page_dmah =
-			drm_pci_alloc(dev, PAGE_SIZE, PAGE_SIZE, 0xffffffff);
-
-		if (!dev_priv->status_page_dmah) {
+		drm_dma_handle_t *dmah;
+#ifdef __FreeBSD__
+		DRM_UNLOCK();
+#endif
+		dmah = drm_pci_alloc(dev, PAGE_SIZE, PAGE_SIZE, 0xffffffff);
+#ifdef __FreeBSD__
+		DRM_LOCK();
+#endif
+		if (!dmah) {
 			i915_dma_cleanup(dev);
 			DRM_ERROR("Can not allocate hardware status page\n");
 			return -ENOMEM;
 		}
-		dev_priv->hw_status_page = dev_priv->status_page_dmah->vaddr;
-		dev_priv->dma_status_page = dev_priv->status_page_dmah->busaddr;
+		dev_priv->status_page_dmah = dmah;
+		dev_priv->hw_status_page = dmah->vaddr;
+		dev_priv->dma_status_page = dmah->busaddr;
 
 		memset(dev_priv->hw_status_page, 0, PAGE_SIZE);
 
diff --git a/sys/dev/drm/mach64_dma.c b/sys/dev/drm/mach64_dma.c
index 1cb7779..6068c85 100644
--- a/sys/dev/drm/mach64_dma.c
+++ b/sys/dev/drm/mach64_dma.c
@@ -837,8 +837,14 @@ static int mach64_bm_dma_test(struct drm_device * dev)
 
 	/* FIXME: get a dma buffer from the freelist here */
 	DRM_DEBUG("Allocating data memory ...\n");
+#ifdef __FreeBSD__
+	DRM_UNLOCK();
+#endif
 	cpu_addr_dmah =
 	    drm_pci_alloc(dev, 0x1000, 0x1000, 0xfffffffful);
+#ifdef __FreeBSD__
+	DRM_LOCK();
+#endif
 	if (!cpu_addr_dmah) {
 		DRM_INFO("data-memory allocation failed!\n");
 		return -ENOMEM;