Am 02.04.23 um 18:48 schrieb Dmitry Osipenko:
Don't assert held dma-buf reservation lock on memory mapping of exported
buffer.
We're going to change dma-buf mmap() locking policy such that exporters
will have to handle the lock. The previous locking policy caused deadlock
problem for DRM drivers in a case of self-imported dma-bufs, it's solved
by moving the lock down to exporters.
I only checked the TTM code path and think that at least that one should
work fine.
Fixes: 39ce25291871 ("drm: Assert held reservation lock for dma-buf mmapping")
This here is not really a "fix" for the previous patch. We just found
that we didn't like the behavior and so reverted the original patch.
A "Reverts..." comment in the commit message would be more appropriate I
think.
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Acked-by: Christian König <christian.koenig@xxxxxxx>
Regards,
Christian.
---
drivers/gpu/drm/drm_prime.c | 2 --
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 2 --
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 2 --
drivers/gpu/drm/tegra/gem.c | 2 --
4 files changed, 8 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 149cd4ff6a3b..cea85e84666f 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -781,8 +781,6 @@ int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
struct drm_gem_object *obj = dma_buf->priv;
struct drm_device *dev = obj->dev;
- dma_resv_assert_held(dma_buf->resv);
-
if (!dev->driver->gem_prime_mmap)
return -ENOSYS;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index fd556a076d05..1df74f7aa3dc 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -97,8 +97,6 @@ static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *
struct drm_i915_private *i915 = to_i915(obj->base.dev);
int ret;
- dma_resv_assert_held(dma_buf->resv);
-
if (obj->base.size < vma->vm_end - vma->vm_start)
return -EINVAL;
diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
index 3abc47521b2c..8e194dbc9506 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -66,8 +66,6 @@ static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
struct drm_gem_object *obj = buffer->priv;
int ret = 0;
- dma_resv_assert_held(buffer->resv);
-
ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
if (ret < 0)
return ret;
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index bce991a2ccc0..871ef5d26523 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -693,8 +693,6 @@ static int tegra_gem_prime_mmap(struct dma_buf *buf, struct vm_area_struct *vma)
struct drm_gem_object *gem = buf->priv;
int err;
- dma_resv_assert_held(buf->resv);
-
err = drm_gem_mmap_obj(gem, gem->size, vma);
if (err < 0)
return err;
