With nouveau fixed all ttm-using drives have the correct nesting of
mmap_sem vs dma_resv, and we can just lock the buffer.
Assuming I didn't screw up anything with my audit of course.
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Christian Koenig <christian.koenig@xxxxxxx>
Cc: Huang Rui <ray.huang@xxxxxxx>
Cc: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Cc: "VMware Graphics" <linux-graphics-maintainer@xxxxxxxxxx>
Cc: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo.c | 34 ---------------------------------
drivers/gpu/drm/ttm/ttm_bo_vm.c | 26 +------------------------
include/drm/ttm/ttm_bo_api.h | 1 -
3 files changed, 1 insertion(+), 60 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 20ff56f27aa4..a952dd624b06 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1954,37 +1954,3 @@ void ttm_bo_swapout_all(struct ttm_bo_device *bdev)
;
}
EXPORT_SYMBOL(ttm_bo_swapout_all);
-
-/**
- * ttm_bo_wait_unreserved - interruptible wait for a buffer object to become
- * unreserved
- *
- * @bo: Pointer to buffer
- */
-int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo)
-{
- int ret;
-
- /*
- * In the absense of a wait_unlocked API,
- * Use the bo::wu_mutex to avoid triggering livelocks due to
- * concurrent use of this function. Note that this use of
- * bo::wu_mutex can go away if we change locking order to
- * mmap_sem -> bo::reserve.
- */
- ret = mutex_lock_interruptible(&bo->wu_mutex);
- if (unlikely(ret != 0))
- return -ERESTARTSYS;
- if (!dma_resv_is_locked(bo->base.resv))
- goto out_unlock;
- ret = dma_resv_lock_interruptible(bo->base.resv, NULL);
- if (ret == -EINTR)
- ret = -ERESTARTSYS;
- if (unlikely(ret != 0))
- goto out_unlock;
- dma_resv_unlock(bo->base.resv);
-
-out_unlock:
- mutex_unlock(&bo->wu_mutex);
- return ret;
-}
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 76eedb963693..505e1787aeea 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -125,31 +125,7 @@ static vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
&bdev->man[bo->mem.mem_type];
struct vm_area_struct cvma;
- /*
- * Work around locking order reversal in fault / nopfn
- * between mmap_sem and bo_reserve: Perform a trylock operation
- * for reserve, and if it fails, retry the fault after waiting
- * for the buffer to become unreserved.
- */
- if (unlikely(!dma_resv_trylock(bo->base.resv))) {
- if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) {
- if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
- ttm_bo_get(bo);
- up_read(&vmf->vma->vm_mm->mmap_sem);
- (void) ttm_bo_wait_unreserved(bo);
- ttm_bo_put(bo);
- }
-
- return VM_FAULT_RETRY;
- }
-
- /*
- * If we'd want to change locking order to
- * mmap_sem -> bo::reserve, we'd use a blocking reserve here
- * instead of retrying the fault...
- */
- return VM_FAULT_NOPAGE;
- }
+ dma_resv_lock(bo->base.resv, NULL);
/*
* Refuse to fault imported pages. This should be handled
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 43c4929a2171..6b50e624e3e2 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -765,7 +765,6 @@ ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
int ttm_bo_swapout(struct ttm_bo_global *glob,
struct ttm_operation_ctx *ctx);
void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
-int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo);
/**
* ttm_bo_uses_embedded_gem_object - check if the given bo uses the
--
2.23.0.rc1
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