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From:   Christoph Hellwig <hch@lst.de>
To:     Juergen Gross <jgross@suse.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, Ben Skeggs <bskeggs@redhat.com>,
        Karol Herbst <kherbst@redhat.com>,
        Lyude Paul <lyude@redhat.com>
Cc:     xen-devel@lists.xenproject.org, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org, nouveau@lists.freedesktop.org
Subject: [PATCH 3/4] drm/nouveau: stop using is_swiotlb_active
Date:   Thu, 18 May 2023 15:42:52 +0200
Message-Id: <20230518134253.909623-4-hch@lst.de>
In-Reply-To: <20230518134253.909623-1-hch@lst.de>
References: <20230518134253.909623-1-hch@lst.de>
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Drivers have no business looking into dma-mapping internals and check
what backend is used.  Unfortunstely the DRM core is still broken and
tries to do plain page allocations instead of using DMA API allocators
by default and uses various bandaids on when to use dma_alloc_coherent.

Switch nouveau to use the same (broken) scheme as amdgpu and radeon
to remove the last driver user of is_swiotlb_active.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/gpu/drm/nouveau/nouveau_ttm.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_ttm.c b/drivers/gpu/drm/nouveau/nouveau_ttm.c
index 1469a88910e45d..486f39f31a38df 100644
--- a/drivers/gpu/drm/nouveau/nouveau_ttm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_ttm.c
@@ -24,9 +24,9 @@
  */
 
 #include <linux/limits.h>
-#include <linux/swiotlb.h>
 
 #include <drm/ttm/ttm_range_manager.h>
+#include <drm/drm_cache.h>
 
 #include "nouveau_drv.h"
 #include "nouveau_gem.h"
@@ -265,7 +265,6 @@ nouveau_ttm_init(struct nouveau_drm *drm)
 	struct nvkm_pci *pci = device->pci;
 	struct nvif_mmu *mmu = &drm->client.mmu;
 	struct drm_device *dev = drm->dev;
-	bool need_swiotlb = false;
 	int typei, ret;
 
 	ret = nouveau_ttm_init_host(drm, 0);
@@ -300,13 +299,10 @@ nouveau_ttm_init(struct nouveau_drm *drm)
 		drm->agp.cma = pci->agp.cma;
 	}
 
-#if IS_ENABLED(CONFIG_SWIOTLB) && IS_ENABLED(CONFIG_X86)
-	need_swiotlb = is_swiotlb_active(dev->dev);
-#endif
-
 	ret = ttm_device_init(&drm->ttm.bdev, &nouveau_bo_driver, drm->dev->dev,
 				  dev->anon_inode->i_mapping,
-				  dev->vma_offset_manager, need_swiotlb,
+				  dev->vma_offset_manager,
+				  drm_need_swiotlb(drm->client.mmu.dmabits),
 				  drm->client.mmu.dmabits <= 32);
 	if (ret) {
 		NV_ERROR(drm, "error initialising bo driver, %d\n", ret);
-- 
2.39.2