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Commit c5b1247b authored by Rob Clark's avatar Rob Clark Committed by Greg Kroah-Hartman
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staging: drm/omap: fix locking issue 



The create/free mmap offset code must be synchronized.  Yet only some
callers of omap_gem_mmap_offset() held struct_mutex.  Leading to various
crashes around drm_mm_insert_helper_range().  (In the free-object path,
which is currently the only place we drm_gem_free_mmap_offset(),
struct_mutex is already held.)

Signed-off-by: default avatarRob Clark <rob@ti.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent a9e8d70c

drivers/staging/omapdrm/omap_gem.c

+14 −4
Original line number Diff line number Diff line
@@ -116,6 +116,9 @@ struct omap_gem_object { 
	} *sync;

};



static int get_pages(struct drm_gem_object *obj, struct page ***pages);

static uint64_t mmap_offset(struct drm_gem_object *obj);



/* To deal with userspace mmap'ings of 2d tiled buffers, which (a) are

 * not necessarily pinned in TILER all the time, and (b) when they are

 * they are not necessarily page aligned, we reserve one or more small
@@ -149,7 +152,7 @@ static void evict_entry(struct drm_gem_object *obj, 
{

	if (obj->dev->dev_mapping) {

		size_t size = PAGE_SIZE * usergart[fmt].height;

		loff_t off = omap_gem_mmap_offset(obj) +

		loff_t off = mmap_offset(obj) +

				(entry->obj_pgoff << PAGE_SHIFT);

		unmap_mapping_range(obj->dev->dev_mapping, off, size, 1);

	}
@@ -189,8 +192,6 @@ static inline bool is_shmem(struct drm_gem_object *obj) 
	return obj->filp != NULL;

}



static int get_pages(struct drm_gem_object *obj, struct page ***pages);



static DEFINE_SPINLOCK(sync_lock);



/** ensure backing pages are allocated */
@@ -251,7 +252,7 @@ static void omap_gem_detach_pages(struct drm_gem_object *obj) 
}



/** get mmap offset */

uint64_t omap_gem_mmap_offset(struct drm_gem_object *obj)

static uint64_t mmap_offset(struct drm_gem_object *obj)

{

	if (!obj->map_list.map) {

		/* Make it mmapable */
@@ -267,6 +268,15 @@ uint64_t omap_gem_mmap_offset(struct drm_gem_object *obj) 
	return (uint64_t)obj->map_list.hash.key << PAGE_SHIFT;

}



uint64_t omap_gem_mmap_offset(struct drm_gem_object *obj)

{

	uint64_t offset;

	mutex_lock(&obj->dev->struct_mutex);

	offset = mmap_offset(obj);

	mutex_unlock(&obj->dev->struct_mutex);

	return offset;

}



/** get mmap size */

size_t omap_gem_mmap_size(struct drm_gem_object *obj)

{