drm/amdgpu/userq: cleanup amdgpu_userq_get/put where not needed

amdgpu_userq_put/get are not needed in case we already holding
the userq_mutex and reference is valid already from queue create
time or from signal ioctl. These additional get/put could be a
potential reason for deadlock in case the ref count reaches zero
and destroy is called which again try to take the userq_mutex.

Due to the above change we avoid deadlock between suspend/restore
calling destroy queues trying to take userq_mutex again.

Cc: Prike Liang <Prike.Liang@amd.com>
Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
index d94f4966fea9b8d7ecae2e6343fb5ab6ae8f922d..b75b44a3169bc04795cc42504bafa2f687d6543a 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
@@ -999,15 +999,11 @@ amdgpu_userq_restore_all(struct amdgpu_userq_mgr *uq_mgr)
 
        /* Resume all the queues for this process */
        xa_for_each(&uq_mgr->userq_xa, queue_id, queue) {
-               queue = amdgpu_userq_get(uq_mgr, queue_id);
-               if (!queue)
-                       continue;
 
                if (!amdgpu_userq_buffer_vas_mapped(queue)) {
                        drm_file_err(uq_mgr->file,
                                     "trying restore queue without va mapping\n");
                        queue->state = AMDGPU_USERQ_STATE_INVALID_VA;
-                       amdgpu_userq_put(queue);
                        continue;
                }
 
@@ -1015,7 +1011,6 @@ amdgpu_userq_restore_all(struct amdgpu_userq_mgr *uq_mgr)
                if (r)
                        ret = r;
 
-               amdgpu_userq_put(queue);
        }
 
        if (ret)
@@ -1252,13 +1247,9 @@ amdgpu_userq_evict_all(struct amdgpu_userq_mgr *uq_mgr)
        amdgpu_userq_detect_and_reset_queues(uq_mgr);
        /* Try to unmap all the queues in this process ctx */
        xa_for_each(&uq_mgr->userq_xa, queue_id, queue) {
-               queue = amdgpu_userq_get(uq_mgr, queue_id);
-               if (!queue)
-                       continue;
                r = amdgpu_userq_preempt_helper(queue);
                if (r)
                        ret = r;
-               amdgpu_userq_put(queue);
        }
 
        if (ret)
@@ -1291,24 +1282,18 @@ amdgpu_userq_wait_for_signal(struct amdgpu_userq_mgr *uq_mgr)
        int ret;
 
        xa_for_each(&uq_mgr->userq_xa, queue_id, queue) {
-               queue = amdgpu_userq_get(uq_mgr, queue_id);
-               if (!queue)
-                       continue;
-
                struct dma_fence *f = queue->last_fence;
 
-               if (!f || dma_fence_is_signaled(f)) {
-                       amdgpu_userq_put(queue);
+               if (!f || dma_fence_is_signaled(f))
                        continue;
-               }
+
                ret = dma_fence_wait_timeout(f, true, msecs_to_jiffies(100));
                if (ret <= 0) {
                        drm_file_err(uq_mgr->file, "Timed out waiting for fence=%llu:%llu\n",
                                     f->context, f->seqno);
-                       amdgpu_userq_put(queue);
+
                        return -ETIMEDOUT;
                }
-               amdgpu_userq_put(queue);
        }
 
        return 0;