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| author | Christian König <christian.koenig@amd.com> | 2019-08-05 15:24:55 +0300 |
|---|---|---|
| committer | Christian König <christian.koenig@amd.com> | 2019-08-13 10:07:58 +0300 |
| commit | 5d344f58da760b226562e7d5199fb73294eb93fa (patch) | |
| tree | dabe9434fb720c4c0d80b7078cccf3acde6e0f9a /drivers | |
| parent | d3c6dd1fb30d3853c2012549affe75c930f4a2f9 (diff) | |
| download | linux-5d344f58da760b226562e7d5199fb73294eb93fa.tar.xz | |
dma-buf: nuke reservation_object seq number
The only remaining use for this is to protect against setting a new exclusive
fence while we grab both exclusive and shared. That can also be archived by
looking if the exclusive fence has changed or not after completing the
operation.
v2: switch setting excl fence to rcu_assign_pointer
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/322380/
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/dma-buf/reservation.c | 24 |
1 files changed, 5 insertions, 19 deletions
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index 90bc6ef03598..f7f4a0858c2a 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -49,12 +49,6 @@ DEFINE_WD_CLASS(reservation_ww_class); EXPORT_SYMBOL(reservation_ww_class); -struct lock_class_key reservation_seqcount_class; -EXPORT_SYMBOL(reservation_seqcount_class); - -const char reservation_seqcount_string[] = "reservation_seqcount"; -EXPORT_SYMBOL(reservation_seqcount_string); - /** * reservation_object_list_alloc - allocate fence list * @shared_max: number of fences we need space for @@ -103,9 +97,6 @@ static void reservation_object_list_free(struct reservation_object_list *list) void reservation_object_init(struct reservation_object *obj) { ww_mutex_init(&obj->lock, &reservation_ww_class); - - __seqcount_init(&obj->seq, reservation_seqcount_string, - &reservation_seqcount_class); RCU_INIT_POINTER(obj->fence, NULL); RCU_INIT_POINTER(obj->fence_excl, NULL); } @@ -282,12 +273,10 @@ void reservation_object_add_excl_fence(struct reservation_object *obj, dma_fence_get(fence); preempt_disable(); - write_seqcount_begin(&obj->seq); - /* write_seqcount_begin provides the necessary memory barrier */ - RCU_INIT_POINTER(obj->fence_excl, fence); + rcu_assign_pointer(obj->fence_excl, fence); + /* pointer update must be visible before we modify the shared_count */ if (old) - old->shared_count = 0; - write_seqcount_end(&obj->seq); + smp_store_mb(old->shared_count, 0); preempt_enable(); /* inplace update, no shared fences */ @@ -368,11 +357,8 @@ retry: old = reservation_object_get_excl(dst); preempt_disable(); - write_seqcount_begin(&dst->seq); - /* write_seqcount_begin provides the necessary memory barrier */ - RCU_INIT_POINTER(dst->fence_excl, new); - RCU_INIT_POINTER(dst->fence, dst_list); - write_seqcount_end(&dst->seq); + rcu_assign_pointer(dst->fence_excl, new); + rcu_assign_pointer(dst->fence, dst_list); preempt_enable(); reservation_object_list_free(src_list); |