drm/i915: Remove dma_resv_prune

The signaled bit is already used for quick testing if a fence is signaled.
On top of that, it's a terrible abuse of dma-fence api, and in the common
case where the object is already locked by the caller, the trylock will fail.

If it were useful, the core dma-api would have exposed the same functionality.

The fact that i915 has a dma_resv_utils.c file should be a warning that the
functionality either belongs in core, or is not very useful at all.
In this case the latter.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[mlankhorst: Improve commit message]
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211021103605.735002-3-maarten.lankhorst@linux.intel.com
Reviewed-by: Matthew Auld <matthew.auld@intel.com> #irc

drivers/gpu/drm/i915/Makefile

@@ -60,7 +60,6 @@ i915-y += i915_drv.o \
 
 # core library code
 i915-y += \
-	dma_resv_utils.o \
 	i915_memcpy.o \
 	i915_mm.o \
 	i915_sw_fence.o \

drivers/gpu/drm/i915/dma_resv_utils.c

-// SPDX-License-Identifier: MIT
-/*
- * Copyright © 2020 Intel Corporation
- */
-
-#include <linux/dma-resv.h>
-
-#include "dma_resv_utils.h"
-
-void dma_resv_prune(struct dma_resv *resv)
-{
-	if (dma_resv_trylock(resv)) {
-		if (dma_resv_test_signaled(resv, true))
-			dma_resv_add_excl_fence(resv, NULL);
-		dma_resv_unlock(resv);
-	}
-}

drivers/gpu/drm/i915/dma_resv_utils.h

-/* SPDX-License-Identifier: MIT */
-/*
- * Copyright © 2020 Intel Corporation
- */
-
-#ifndef DMA_RESV_UTILS_H
-#define DMA_RESV_UTILS_H
-
-struct dma_resv;
-
-void dma_resv_prune(struct dma_resv *resv);
-
-#endif /* DMA_RESV_UTILS_H */

drivers/gpu/drm/i915/gem/i915_gem_shrinker.c

@@ -15,7 +15,6 @@
 
 #include "gt/intel_gt_requests.h"
 
-#include "dma_resv_utils.h"
 #include "i915_trace.h"
 
 static bool swap_available(void)
@@ -235,8 +234,6 @@ i915_gem_shrink(struct i915_gem_ww_ctx *ww,
 					i915_gem_object_unlock(obj);
 			}
 
-			dma_resv_prune(obj->base.resv);
-
 			scanned += obj->base.size >> PAGE_SHIFT;
 skip:
 			i915_gem_object_put(obj);

drivers/gpu/drm/i915/gem/i915_gem_wait.c

@@ -10,7 +10,6 @@
 
 #include "gt/intel_engine.h"
 
-#include "dma_resv_utils.h"
 #include "i915_gem_ioctls.h"
 #include "i915_gem_object.h"
 
@@ -52,13 +51,6 @@ i915_gem_object_wait_reservation(struct dma_resv *resv,
 	}
 	dma_resv_iter_end(&cursor);
 
-	/*
-	 * Opportunistically prune the fences iff we know they have *all* been
-	 * signaled.
-	 */
-	if (timeout > 0)
-		dma_resv_prune(resv);
-
 	return ret;
 }