On Fri, Sep 17, 2021 at 03:27:55PM +0200, Daniel Vetter wrote:
On Fri, Sep 17, 2021 at 02:34:49PM +0200, Christian König wrote:
A simpler version of the iterator to be used when the dma_resv object is locked.
Signed-off-by: Christian König christian.koenig@amd.com
drivers/dma-buf/dma-resv.c | 33 +++++++++++++++++++++++++++++++++ include/linux/dma-resv.h | 17 +++++++++++++++++ 2 files changed, 50 insertions(+)
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 3e77cad2c9d4..a3c79a99fb44 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -384,6 +384,39 @@ struct dma_fence *dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor, } EXPORT_SYMBOL_GPL(dma_resv_iter_walk_unlocked); +/**
- dma_resv_iter_walk - walk over fences in a dma_resv obj
- @cursor: cursor to record the current position
- @first: if we should start over
- Return all the fences in the dma_resv object while holding the
- dma_resv::lock.
I think we should document here that the fence is valid for as long as the dma_resv_lock is held, which is not like the _unlocked version, where the fence stops being valid either on the next call to iter_next() or on the call to iter_end() to clean up everything.
Might be good to clarify that also for the unlocked version to be really precise here when the fence is valid and when not. -Daniel
- */
+struct dma_fence *dma_resv_iter_walk(struct dma_resv_iter *cursor, bool first) +{
- dma_resv_assert_held(cursor->obj);
- cursor->is_first = first;
- if (first) {
struct dma_fence *fence;cursor->index = -1;cursor->fences = dma_resv_shared_list(cursor->obj);fence = dma_resv_excl_fence(cursor->obj);if (fence)return fence;- }
I think you can still use the shared iter_begin/end functions even with my suggestions for patch 1, but would mean changes here too.
- if (!cursor->all_fences || !cursor->fences ||
++cursor->index >= cursor->fences->shared_count)return NULL;- return rcu_dereference_protected(cursor->fences->shared[cursor->index],
dma_resv_held(cursor->obj));+} +EXPORT_SYMBOL_GPL(dma_resv_iter_walk);
/**
- dma_resv_copy_fences - Copy all fences from src to dst.
- @dst: the destination reservation object
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 693d16117153..8c968f8c9d33 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -179,6 +179,7 @@ struct dma_resv_iter { struct dma_fence *dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor, bool first); +struct dma_fence *dma_resv_iter_walk(struct dma_resv_iter *cursor, bool first); /**
- dma_resv_iter_begin - initialize a dma_resv_iter object
@@ -233,6 +234,22 @@ static inline bool dma_resv_iter_is_exclusive(struct dma_resv_iter *cursor) for (fence = dma_resv_iter_walk_unlocked(cursor, true); \ fence; fence = dma_resv_iter_walk_unlocked(cursor, false)) +/**
- 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
&dma_resv.lock is how you reference struct members in kerneldoc. I think you had this also in patch 1.
- well. The cursor initialisation is part of the iterator.
Please also link to the iter_begin/end functions here.
Aside from doc nits and obviously changes due to changes in patch 1 (if we do them), this looks good. -Daniel
- */
+#define dma_resv_for_each_fence(cursor, obj, all_fences, fence) \
- for (dma_resv_iter_begin(cursor, obj, all_fences), \
fence = dma_resv_iter_walk(cursor, true); fence; \fence = dma_resv_iter_walk(cursor, false))#define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base) #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base) -- 2.25.1
-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch