[PATCH AUTOSEL 4.19 17/37] drm/msm: stop abusing dma_map/unmap for cache

Sasha Levin
2019-10-25T14:04:09Z

From: Rob Clark <robdclark@chromium.org>

[ Upstream commit 0036bc73ccbe7e600a3468bf8e8879b122252274 ]

Recently splats like this started showing up:

WARNING: CPU: 4 PID: 251 at drivers/iommu/dma-iommu.c:451 __iommu_dma_unmap+0xb8/0xc0
Modules linked in: ath10k_snoc ath10k_core fuse msm ath mac80211 uvcvideo cfg80211 videobuf2_vmalloc videobuf2_memops vide
CPU: 4 PID: 251 Comm: kworker/u16:4 Tainted: G W 5.2.0-rc5-next-20190619+ #2317
Hardware name: LENOVO 81JL/LNVNB161216, BIOS 9UCN23WW(V1.06) 10/25/2018
Workqueue: msm msm_gem_free_work [msm]
pstate: 80c00005 (Nzcv daif +PAN +UAO)
pc : __iommu_dma_unmap+0xb8/0xc0
lr : __iommu_dma_unmap+0x54/0xc0
sp : ffff0000119abce0
x29: ffff0000119abce0 x28: 0000000000000000
x27: ffff8001f9946648 x26: ffff8001ec271068
x25: 0000000000000000 x24: ffff8001ea3580a8
x23: ffff8001f95ba010 x22: ffff80018e83ba88
x21: ffff8001e548f000 x20: fffffffffffff000
x19: 0000000000001000 x18: 00000000c00001fe
x17: 0000000000000000 x16: 0000000000000000
x15: ffff000015b70068 x14: 0000000000000005
x13: 0003142cc1be1768 x12: 0000000000000001
x11: ffff8001f6de9100 x10: 0000000000000009
x9 : ffff000015b78000 x8 : 0000000000000000
x7 : 0000000000000001 x6 : fffffffffffff000
x5 : 0000000000000fff x4 : ffff00001065dbc8
x3 : 000000000000000d x2 : 0000000000001000
x1 : fffffffffffff000 x0 : 0000000000000000
Call trace:
__iommu_dma_unmap+0xb8/0xc0
iommu_dma_unmap_sg+0x98/0xb8
put_pages+0x5c/0xf0 [msm]
msm_gem_free_work+0x10c/0x150 [msm]
process_one_work+0x1e0/0x330
worker_thread+0x40/0x438
kthread+0x12c/0x130
ret_from_fork+0x10/0x18
---[ end trace afc0dc5ab81a06bf ]---

Not quite sure what triggered that, but we really shouldn't be abusing
dma_{map,unmap}_sg() for cache maint.

Cc: Stephen Boyd <sboyd@kernel.org>
Tested-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190630124735.27786-1-robdclark@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/msm/msm_gem.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index f59ca27a4a357..93b20ad23c23f 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -108,7 +108,7 @@ static struct page **get_pages(struct drm_gem_object *obj)
* because display controller, GPU, etc. are not coherent:
*/
if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED))
- dma_map_sg(dev->dev, msm_obj->sgt->sgl,
+ dma_sync_sg_for_device(dev->dev, msm_obj->sgt->sgl,
msm_obj->sgt->nents, DMA_BIDIRECTIONAL);
}

@@ -138,7 +138,7 @@ static void put_pages(struct drm_gem_object *obj)
* GPU, etc. are not coherent:
*/
if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED))
- dma_unmap_sg(obj->dev->dev, msm_obj->sgt->sgl,
+ dma_sync_sg_for_cpu(obj->dev->dev, msm_obj->sgt->sgl,
msm_obj->sgt->nents,
DMA_BIDIRECTIONAL);

--
2.20.1