[PATCH] drm/amdgpu: Fix validating flush_gpu_tlb_pasid()

["Timur Kristóf" <timur.kristof@gmail.com>]

When a function holds a lock and we return without unlocking it,
it deadlocks the kernel. We should always unlock before returning.

This commit fixes suspend/resume on SI.
Tested on two Tahiti GPUs: FirePro W9000 and R9 280X.

Fixes: bc2dea30038a ("drm/amdgpu: validate the flush_gpu_tlb_pasid()")
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
index 0e67fa4338ff..4fa24be1bf45 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
@@ -769,7 +769,7 @@ int amdgpu_gmc_flush_gpu_tlb_pasid(struct amdgpu_device *adev, uint16_t pasid,
 	struct amdgpu_ring *ring = &adev->gfx.kiq[inst].ring;
 	struct amdgpu_kiq *kiq = &adev->gfx.kiq[inst];
 	unsigned int ndw;
-	int r, cnt = 0;
+	int r = 0, cnt = 0;
 	uint32_t seq;
 
 	/*
@@ -782,7 +782,7 @@ int amdgpu_gmc_flush_gpu_tlb_pasid(struct amdgpu_device *adev, uint16_t pasid,
 	if (!adev->gmc.flush_pasid_uses_kiq || !ring->sched.ready) {
 
 		if (!adev->gmc.gmc_funcs->flush_gpu_tlb_pasid)
-			return 0;
+			goto error_unlock_reset;
 
 		if (adev->gmc.flush_tlb_needs_extra_type_2)
 			adev->gmc.gmc_funcs->flush_gpu_tlb_pasid(adev, pasid,
@@ -797,7 +797,6 @@ int amdgpu_gmc_flush_gpu_tlb_pasid(struct amdgpu_device *adev, uint16_t pasid,
 		adev->gmc.gmc_funcs->flush_gpu_tlb_pasid(adev, pasid,
 							 flush_type, all_hub,
 							 inst);
-		r = 0;
 	} else {
 		/* 2 dwords flush + 8 dwords fence */
 		ndw = kiq->pmf->invalidate_tlbs_size + 8;
-- 
2.52.0