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dma-buf: add dma_resv_for_each_fence v3

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A simpler version of the iterator to be used when the dma_resv object is
locked.

v2: fix index check here as well
v3: minor coding improvement, some documentation cleanup

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211006123609.2026-1-christian.koenig@amd.com
This commit is contained in:
Christian König 2021-06-15 15:10:03 +02:00
parent a0a33067b9
commit 5baaac3184
2 changed files with 71 additions and 0 deletions
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51
drivers/dma-buf/dma-resv.c
View file

@ -423,6 +423,57 @@ struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor)
}
EXPORT_SYMBOL(dma_resv_iter_next_unlocked);
/**
* dma_resv_iter_first - first fence from a locked dma_resv object
* @cursor: cursor to record the current position
*
* Return the first fence in the dma_resv object while holding the
* &dma_resv.lock.
*/
struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor)
{
struct dma_fence *fence;
dma_resv_assert_held(cursor->obj);
cursor->index = 0;
if (cursor->all_fences)
cursor->fences = dma_resv_shared_list(cursor->obj);
else
cursor->fences = NULL;
fence = dma_resv_excl_fence(cursor->obj);
if (!fence)
fence = dma_resv_iter_next(cursor);
cursor->is_restarted = true;
return fence;
}
EXPORT_SYMBOL_GPL(dma_resv_iter_first);
/**
* dma_resv_iter_next - next fence from a locked dma_resv object
* @cursor: cursor to record the current position
*
* Return the next fences from the dma_resv object while holding the
* &dma_resv.lock.
*/
struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor)
{
unsigned int idx;
dma_resv_assert_held(cursor->obj);
cursor->is_restarted = false;
if (!cursor->fences || cursor->index >= cursor->fences->shared_count)
return NULL;
idx = cursor->index++;
return rcu_dereference_protected(cursor->fences->shared[idx],
dma_resv_held(cursor->obj));
}
EXPORT_SYMBOL_GPL(dma_resv_iter_next);
/**
* dma_resv_copy_fences - Copy all fences from src to dst.
* @dst: the destination reservation object

20
include/linux/dma-resv.h
View file

@ -179,6 +179,8 @@ struct dma_resv_iter {
struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor);
/**
* dma_resv_iter_begin - initialize a dma_resv_iter object
@ -244,6 +246,24 @@ static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor)
for (fence = dma_resv_iter_first_unlocked(cursor); \
fence; fence = dma_resv_iter_next_unlocked(cursor))
/**
* dma_resv_for_each_fence - fence iterator
* @cursor: a struct dma_resv_iter pointer
* @obj: a dma_resv object pointer
* @all_fences: true if all fences should be returned
* @fence: the current fence
*
* Iterate over the fences in a struct dma_resv object while holding the
* &dma_resv.lock. @all_fences controls if the shared fences are returned as
* well. The cursor initialisation is part of the iterator and the fence stays
* valid as long as the lock is held and so no extra reference to the fence is
* taken.
*/
#define dma_resv_for_each_fence(cursor, obj, all_fences, fence) \
for (dma_resv_iter_begin(cursor, obj, all_fences), \
fence = dma_resv_iter_first(cursor); fence; \
fence = dma_resv_iter_next(cursor))
#define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
#define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)