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Commit d7d8aac7 authored by Thomas Hellstrom's avatar Thomas Hellstrom Committed by Dave Airlie
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drm: fix up mmap locking in preparation for ttm changes 



This change is needed to protect againt disappearing maps which aren't common.
The map lists are protected using sturct_mutex but drm_mmap never locked it.

Signed-off-by: default avatarDave Airlie <airlied@linux.ie>
parent 040ac320

drivers/char/drm/drm_vm.c

+26 −9
Original line number Diff line number Diff line
@@ -413,7 +413,7 @@ static struct vm_operations_struct drm_vm_sg_ops = { 
 * Create a new drm_vma_entry structure as the \p vma private data entry and

 * add it to drm_device::vmalist.

 */

static void drm_vm_open(struct vm_area_struct *vma)

static void drm_vm_open_locked(struct vm_area_struct *vma)

{

	drm_file_t *priv = vma->vm_file->private_data;

	drm_device_t *dev = priv->head->dev;
@@ -425,15 +425,23 @@ static void drm_vm_open(struct vm_area_struct *vma) 


	vma_entry = drm_alloc(sizeof(*vma_entry), DRM_MEM_VMAS);

	if (vma_entry) {

		mutex_lock(&dev->struct_mutex);

		vma_entry->vma = vma;

		vma_entry->next = dev->vmalist;

		vma_entry->pid = current->pid;

		dev->vmalist = vma_entry;

		mutex_unlock(&dev->struct_mutex);

	}

}



static void drm_vm_open(struct vm_area_struct *vma)

{

	drm_file_t *priv = vma->vm_file->private_data;

	drm_device_t *dev = priv->head->dev;



	mutex_lock(&dev->struct_mutex);

	drm_vm_open_locked(vma);

	mutex_unlock(&dev->struct_mutex);

}



/**

 * \c close method for all virtual memory types.

 *
@@ -484,7 +492,6 @@ static int drm_mmap_dma(struct file *filp, struct vm_area_struct *vma) 
	drm_device_dma_t *dma;

	unsigned long length = vma->vm_end - vma->vm_start;



	lock_kernel();

	dev = priv->head->dev;

	dma = dev->dma;

	DRM_DEBUG("start = 0x%lx, end = 0x%lx, page offset = 0x%lx\n",
@@ -492,10 +499,8 @@ static int drm_mmap_dma(struct file *filp, struct vm_area_struct *vma) 


	/* Length must match exact page count */

	if (!dma || (length >> PAGE_SHIFT) != dma->page_count) {

		unlock_kernel();

		return -EINVAL;

	}

	unlock_kernel();



	if (!capable(CAP_SYS_ADMIN) &&

	    (dma->flags & _DRM_DMA_USE_PCI_RO)) {
@@ -518,7 +523,7 @@ static int drm_mmap_dma(struct file *filp, struct vm_area_struct *vma) 
	vma->vm_flags |= VM_RESERVED;	/* Don't swap */



	vma->vm_file = filp;	/* Needed for drm_vm_open() */

	drm_vm_open(vma);

	drm_vm_open_locked(vma);

	return 0;

}
@@ -553,7 +558,7 @@ EXPORT_SYMBOL(drm_core_get_reg_ofs); 
 * according to the mapping type and remaps the pages. Finally sets the file

 * pointer and calls vm_open().

 */

int drm_mmap(struct file *filp, struct vm_area_struct *vma)

static int drm_mmap_locked(struct file *filp, struct vm_area_struct *vma)

{

	drm_file_t *priv = filp->private_data;

	drm_device_t *dev = priv->head->dev;
@@ -667,8 +672,20 @@ int drm_mmap(struct file *filp, struct vm_area_struct *vma) 
	vma->vm_flags |= VM_RESERVED;	/* Don't swap */



	vma->vm_file = filp;	/* Needed for drm_vm_open() */

	drm_vm_open(vma);

	drm_vm_open_locked(vma);

	return 0;

}



int drm_mmap(struct file *filp, struct vm_area_struct *vma)

{

	drm_file_t *priv = filp->private_data;

	drm_device_t *dev = priv->head->dev;

	int ret;



	mutex_lock(&dev->struct_mutex);

	ret = drm_mmap_locked(filp, vma);

	mutex_unlock(&dev->struct_mutex);



	return ret;

}

EXPORT_SYMBOL(drm_mmap);