Am 08.08.2017 um 09:49 schrieb Liu, Monk:
Please add some spaces in "src?&src->refcount:NULL" after each operator.
With that fixed the patch is Reviewed-by: Christian König 
<christian.koe...@amd.com>.
Actually this " src?&src->refcount:NULL" is totally removed in second cleanup 
patch ...


Yeah, that obviously works as well :)

Christian.


BR Monk

-----Original Message-----
From: Christian König [mailto:deathsim...@vodafone.de]
Sent: Tuesday, August 8, 2017 3:44 PM
To: Liu, Monk <monk....@amd.com>; amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH libdrm 1/2] drm:fix race issue between two bo functions(v2)

Am 08.08.2017 um 09:34 schrieb Monk Liu:
From: Monk Liu <monk....@amd.com>

there is race issue between two threads on amdgpu_bo_reference and
amdgpu_bo_import, this patch tends to fix it by moving the
pthread_mutex_lock out of bo_free_internal and move to bo_reference to
cover the update_reference part.

The mutex_unlock in bo_import should also cover bo refcount
increasement.

Change-Id: I1f65eacf74cd28cc0d3a71ef2f7a19b890d63c29
Signed-off-by: Monk Liu <monk....@amd.com>
---
   amdgpu/amdgpu_bo.c       |  5 +----
   amdgpu/amdgpu_internal.h | 15 ++++++++++++---
   2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/amdgpu/amdgpu_bo.c b/amdgpu/amdgpu_bo.c index
07eb743..82f38c0 100644
--- a/amdgpu/amdgpu_bo.c
+++ b/amdgpu/amdgpu_bo.c
@@ -55,14 +55,12 @@ static void amdgpu_close_kms_handle(amdgpu_device_handle 
dev,
   void amdgpu_bo_free_internal(amdgpu_bo_handle bo)
   {
        /* Remove the buffer from the hash tables. */
-       pthread_mutex_lock(&bo->dev->bo_table_mutex);
        util_hash_table_remove(bo->dev->bo_handles,
                               (void*)(uintptr_t)bo->handle);
        if (bo->flink_name) {
                util_hash_table_remove(bo->dev->bo_flink_names,
                                       (void*)(uintptr_t)bo->flink_name);
        }
-       pthread_mutex_unlock(&bo->dev->bo_table_mutex);
/* Release CPU access. */
        if (bo->cpu_map_count > 0) {
@@ -340,10 +338,9 @@ int amdgpu_bo_import(amdgpu_device_handle dev,
        }
if (bo) {
-               pthread_mutex_unlock(&dev->bo_table_mutex);
-
                /* The buffer already exists, just bump the refcount. */
                atomic_inc(&bo->refcount);
+               pthread_mutex_unlock(&dev->bo_table_mutex);
output->buf_handle = bo;
                output->alloc_size = bo->alloc_size; diff --git
a/amdgpu/amdgpu_internal.h b/amdgpu/amdgpu_internal.h index
0508131..79da0e7 100644
--- a/amdgpu/amdgpu_internal.h
+++ b/amdgpu/amdgpu_internal.h
@@ -143,7 +143,7 @@ void amdgpu_vamgr_deinit(struct amdgpu_bo_va_mgr *mgr);
   uint64_t amdgpu_vamgr_find_va(struct amdgpu_bo_va_mgr *mgr, uint64_t size,
                                uint64_t alignment, uint64_t base_required);
-void amdgpu_vamgr_free_va(struct amdgpu_bo_va_mgr *mgr, uint64_t va,
+void amdgpu_vamgr_free_va(struct amdgpu_bo_va_mgr *mgr, uint64_t va,
                                uint64_t size);
int amdgpu_query_gpu_info_init(amdgpu_device_handle dev); @@ -193,8
+193,17 @@ static inline bool update_references(atomic_t *dst, atomic_t *src)
   static inline void amdgpu_bo_reference(struct amdgpu_bo **dst,
                                        struct amdgpu_bo *src)
   {
-       if (update_references(&(*dst)->refcount, &src->refcount))
-               amdgpu_bo_free_internal(*dst);
+       pthread_mutex_t *mlock;
+       struct amdgpu_bo* bo = *dst;
+
+       assert(bo != NULL);
+       mlock = &bo->dev->bo_table_mutex;
+       pthread_mutex_lock(mlock);
+
+       if (update_references(&bo->refcount, src?&src->refcount:NULL))
Please add some spaces in "src?&src->refcount:NULL" after each operator.

With that fixed the patch is Reviewed-by: Christian König 
<christian.koe...@amd.com>.

Regards,
Christian.

+               amdgpu_bo_free_internal(bo);
+
+       pthread_mutex_unlock(mlock);
        *dst = src;
   }

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