Add a new helper to get a consistent set of pointers from the reservation object. While at it group all access helpers together in the header file.
Signed-off-by: Christian König christian.koenig@amd.com --- drivers/dma-buf/dma-buf.c | 27 ++------ drivers/dma-buf/reservation.c | 60 ++++++------------ include/linux/reservation.h | 113 ++++++++++++++++++++-------------- 3 files changed, 94 insertions(+), 106 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index f45bfb29ef96..0d11b3cc961e 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -199,7 +199,7 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) struct reservation_object_list *fobj; struct dma_fence *fence_excl; __poll_t events; - unsigned shared_count, seq; + unsigned shared_count;
dmabuf = file->private_data; if (!dmabuf || !dmabuf->resv) @@ -213,20 +213,12 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) if (!events) return 0;
-retry: - seq = read_seqcount_begin(&resv->seq); rcu_read_lock(); - - fobj = rcu_dereference(resv->fence); + reservation_object_fences(resv, &fence_excl, &fobj); if (fobj) shared_count = fobj->shared_count; else shared_count = 0; - fence_excl = rcu_dereference(resv->fence_excl); - if (read_seqcount_retry(&resv->seq, seq)) { - rcu_read_unlock(); - goto retry; - }
if (fence_excl && (!(events & EPOLLOUT) || shared_count == 0)) { struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl; @@ -1157,7 +1149,6 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) struct reservation_object *robj; struct reservation_object_list *fobj; struct dma_fence *fence; - unsigned seq; int count = 0, attach_count, shared_count, i; size_t size = 0;
@@ -1188,16 +1179,10 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) buf_obj->name ?: "");
robj = buf_obj->resv; - while (true) { - seq = read_seqcount_begin(&robj->seq); - rcu_read_lock(); - fobj = rcu_dereference(robj->fence); - shared_count = fobj ? fobj->shared_count : 0; - fence = rcu_dereference(robj->fence_excl); - if (!read_seqcount_retry(&robj->seq, seq)) - break; - rcu_read_unlock(); - } + rcu_read_lock(); + reservation_object_fences(robj, &fence, &fobj); + shared_count = fobj ? fobj->shared_count : 0; + rcu_read_unlock();
if (fence) seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index 7505eb289023..839d72af7ad8 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -316,9 +316,9 @@ int reservation_object_copy_fences(struct reservation_object *dst, reservation_object_assert_held(dst);
rcu_read_lock(); - src_list = rcu_dereference(src->fence);
retry: + reservation_object_fences(src, &new, &src_list); if (src_list) { unsigned shared_count = src_list->shared_count;
@@ -329,7 +329,7 @@ int reservation_object_copy_fences(struct reservation_object *dst, return -ENOMEM;
rcu_read_lock(); - src_list = rcu_dereference(src->fence); + reservation_object_fences(src, &new, &src_list); if (!src_list || src_list->shared_count > shared_count) { kfree(dst_list); goto retry; @@ -346,7 +346,6 @@ int reservation_object_copy_fences(struct reservation_object *dst,
if (!dma_fence_get_rcu(fence)) { reservation_object_list_free(dst_list); - src_list = rcu_dereference(src->fence); goto retry; }
@@ -361,7 +360,10 @@ int reservation_object_copy_fences(struct reservation_object *dst, dst_list = NULL; }
- new = dma_fence_get_rcu_safe(&src->fence_excl); + if (new && !dma_fence_get_rcu(new)) { + reservation_object_list_free(dst_list); + goto retry; + } rcu_read_unlock();
src_list = reservation_object_get_list(dst); @@ -407,19 +409,17 @@ int reservation_object_get_fences_rcu(struct reservation_object *obj,
do { struct reservation_object_list *fobj; - unsigned int i, seq; + unsigned int i; size_t sz = 0;
shared_count = i = 0;
rcu_read_lock(); - seq = read_seqcount_begin(&obj->seq); + reservation_object_fences(obj, &fence_excl, &fobj);
- fence_excl = rcu_dereference(obj->fence_excl); if (fence_excl && !dma_fence_get_rcu(fence_excl)) goto unlock;
- fobj = rcu_dereference(obj->fence); if (fobj) sz += sizeof(*shared) * fobj->shared_max;
@@ -455,7 +455,7 @@ int reservation_object_get_fences_rcu(struct reservation_object *obj, } }
- if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) { + if (i != shared_count) { while (i--) dma_fence_put(shared[i]); dma_fence_put(fence_excl); @@ -499,18 +499,18 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj, bool wait_all, bool intr, unsigned long timeout) { + struct reservation_object_list *fobj; struct dma_fence *fence; - unsigned seq, shared_count; + unsigned shared_count; long ret = timeout ? timeout : 1; int i;
retry: shared_count = 0; - seq = read_seqcount_begin(&obj->seq); rcu_read_lock(); i = -1;
- fence = rcu_dereference(obj->fence_excl); + reservation_object_fences(obj, &fence, &fobj); if (fence && !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) { if (!dma_fence_get_rcu(fence)) goto unlock_retry; @@ -525,9 +525,6 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj, }
if (wait_all) { - struct reservation_object_list *fobj = - rcu_dereference(obj->fence); - if (fobj) shared_count = fobj->shared_count;
@@ -553,11 +550,6 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
rcu_read_unlock(); if (fence) { - if (read_seqcount_retry(&obj->seq, seq)) { - dma_fence_put(fence); - goto retry; - } - ret = dma_fence_wait_timeout(fence, intr, ret); dma_fence_put(fence); if (ret > 0 && wait_all && (i + 1 < shared_count)) @@ -602,21 +594,20 @@ reservation_object_test_signaled_single(struct dma_fence *passed_fence) bool reservation_object_test_signaled_rcu(struct reservation_object *obj, bool test_all) { - unsigned seq, shared_count; + struct reservation_object_list *fobj; + struct dma_fence *fence_excl; + unsigned shared_count; int ret;
rcu_read_lock(); retry: ret = true; shared_count = 0; - seq = read_seqcount_begin(&obj->seq);
+ reservation_object_fences(obj, &fence_excl, &fobj); if (test_all) { unsigned i;
- struct reservation_object_list *fobj = - rcu_dereference(obj->fence); - if (fobj) shared_count = fobj->shared_count;
@@ -629,23 +620,12 @@ bool reservation_object_test_signaled_rcu(struct reservation_object *obj, else if (!ret) break; } - - if (read_seqcount_retry(&obj->seq, seq)) - goto retry; }
- if (!shared_count) { - struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl); - - if (fence_excl) { - ret = reservation_object_test_signaled_single( - fence_excl); - if (ret < 0) - goto retry; - - if (read_seqcount_retry(&obj->seq, seq)) - goto retry; - } + if (!shared_count && fence_excl) { + ret = reservation_object_test_signaled_single(fence_excl); + if (ret < 0) + goto retry; }
rcu_read_unlock(); diff --git a/include/linux/reservation.h b/include/linux/reservation.h index 56b782fec49b..b8b8273eef00 100644 --- a/include/linux/reservation.h +++ b/include/linux/reservation.h @@ -81,6 +81,51 @@ struct reservation_object { #define reservation_object_assert_held(obj) \ lockdep_assert_held(&(obj)->lock.base)
+/** + * reservation_object_get_excl - get the reservation object's + * exclusive fence, with update-side lock held + * @obj: the reservation object + * + * Returns the exclusive fence (if any). Does NOT take a + * reference. Writers must hold obj->lock, readers may only + * hold a RCU read side lock. + * + * RETURNS + * The exclusive fence or NULL + */ +static inline struct dma_fence * +reservation_object_get_excl(struct reservation_object *obj) +{ + return rcu_dereference_protected(obj->fence_excl, + reservation_object_held(obj)); +} + +/** + * reservation_object_get_excl_rcu - get the reservation object's + * exclusive fence, without lock held. + * @obj: the reservation object + * + * If there is an exclusive fence, this atomically increments it's + * reference count and returns it. + * + * RETURNS + * The exclusive fence or NULL if none + */ +static inline struct dma_fence * +reservation_object_get_excl_rcu(struct reservation_object *obj) +{ + struct dma_fence *fence; + + if (!rcu_access_pointer(obj->fence_excl)) + return NULL; + + rcu_read_lock(); + fence = dma_fence_get_rcu_safe(&obj->fence_excl); + rcu_read_unlock(); + + return fence; +} + /** * reservation_object_get_list - get the reservation object's * shared fence list, with update-side lock held @@ -96,6 +141,29 @@ reservation_object_get_list(struct reservation_object *obj) reservation_object_held(obj)); }
+/** + * reservation_object_fences - read consistent fence pointers + * @obj: reservation object where we get the fences from + * @excl: pointer for the exclusive fence + * @list: pointer for the shared fence list + * + * Make sure we have a consisten exclusive fence and shared fence list. + * Must be called with rcu read side lock held. + */ +static inline void +reservation_object_fences(struct reservation_object *obj, + struct dma_fence **excl, + struct reservation_object_list **list) +{ + unsigned int seq; + + do { + seq = read_seqcount_begin(&obj->seq); + *excl = rcu_dereference(obj->fence_excl); + *list = rcu_dereference(obj->fence); + } while (read_seqcount_retry(&obj->seq, seq)); +} + /** * reservation_object_lock - lock the reservation object * @obj: the reservation object @@ -239,51 +307,6 @@ reservation_object_unlock(struct reservation_object *obj) ww_mutex_unlock(&obj->lock); }
-/** - * reservation_object_get_excl - get the reservation object's - * exclusive fence, with update-side lock held - * @obj: the reservation object - * - * Returns the exclusive fence (if any). Does NOT take a - * reference. Writers must hold obj->lock, readers may only - * hold a RCU read side lock. - * - * RETURNS - * The exclusive fence or NULL - */ -static inline struct dma_fence * -reservation_object_get_excl(struct reservation_object *obj) -{ - return rcu_dereference_protected(obj->fence_excl, - reservation_object_held(obj)); -} - -/** - * reservation_object_get_excl_rcu - get the reservation object's - * exclusive fence, without lock held. - * @obj: the reservation object - * - * If there is an exclusive fence, this atomically increments it's - * reference count and returns it. - * - * RETURNS - * The exclusive fence or NULL if none - */ -static inline struct dma_fence * -reservation_object_get_excl_rcu(struct reservation_object *obj) -{ - struct dma_fence *fence; - - if (!rcu_access_pointer(obj->fence_excl)) - return NULL; - - rcu_read_lock(); - fence = dma_fence_get_rcu_safe(&obj->fence_excl); - rcu_read_unlock(); - - return fence; -} - void reservation_object_init(struct reservation_object *obj); void reservation_object_fini(struct reservation_object *obj); int reservation_object_reserve_shared(struct reservation_object *obj,