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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2019-10-03 23:01:00 +0200 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2019-10-04 14:43:43 +0200 |
| commit | 3dda22d3dcd1fc39e7867b2c5f5fc8fa79fdefcc (patch) | |
| tree | f7074121eac9203209c3de91008807438b44719f /drivers/gpu/drm/drm_mm.c | |
| parent | drm/mm: Convert drm_mm_node booleans to bitops (diff) | |
| download | linux-3dda22d3dcd1fc39e7867b2c5f5fc8fa79fdefcc.tar.xz linux-3dda22d3dcd1fc39e7867b2c5f5fc8fa79fdefcc.zip | |
drm/mm: Use clear_bit_unlock() for releasing the drm_mm_node()
A few callers need to serialise the destruction of their drm_mm_node and
ensure it is removed from the drm_mm before freeing. However, to be
completely sure that any access from another thread is complete before
we free the struct, we require the RELEASE semantics of
clear_bit_unlock().
This allows the conditional locking such as
Thread A Thread B
mutex_lock(mm_lock); if (drm_mm_node_allocated(node)) {
drm_mm_node_remove(node); mutex_lock(mm_lock);
mutex_unlock(mm_lock); if (drm_mm_node_allocated(node))
drm_mm_node_remove(node);
mutex_unlock(mm_lock);
}
kfree(node);
to serialise correctly without any lingering accesses from A to the
freed node. Allocation / insertion of the node is assumed never to race
with removal or eviction scanning.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191003210100.22250-5-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/drm_mm.c')
| -rw-r--r-- | drivers/gpu/drm/drm_mm.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index a9cab5e53731..2a6e34663146 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -424,9 +424,9 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node) node->mm = mm; + __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); list_add(&node->node_list, &hole->node_list); drm_mm_interval_tree_add_node(hole, node); - __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); node->hole_size = 0; rm_hole(hole); @@ -543,9 +543,9 @@ int drm_mm_insert_node_in_range(struct drm_mm * const mm, node->color = color; node->hole_size = 0; + __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); list_add(&node->node_list, &hole->node_list); drm_mm_interval_tree_add_node(hole, node); - __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); rm_hole(hole); if (adj_start > hole_start) @@ -589,11 +589,12 @@ void drm_mm_remove_node(struct drm_mm_node *node) drm_mm_interval_tree_remove(node, &mm->interval_tree); list_del(&node->node_list); - __clear_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); if (drm_mm_hole_follows(prev_node)) rm_hole(prev_node); add_hole(prev_node); + + clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &node->flags); } EXPORT_SYMBOL(drm_mm_remove_node); @@ -614,6 +615,7 @@ void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new) *new = *old; + __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &new->flags); list_replace(&old->node_list, &new->node_list); rb_replace_node_cached(&old->rb, &new->rb, &mm->interval_tree); @@ -627,8 +629,7 @@ void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new) &mm->holes_addr); } - __clear_bit(DRM_MM_NODE_ALLOCATED_BIT, &old->flags); - __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &new->flags); + clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &old->flags); } EXPORT_SYMBOL(drm_mm_replace_node); |