drm: Don't assert held reservation lock for dma-buf mmapping

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 once these
drivers are moved to use reservation lock universally. The problem is
solved by moving the lock down to exporters. This patch prepares DRM
drivers for the locking policy update.

Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230529223935.2672495-2-dmitry.osipenko@collabora.com
Link: https://patchwork.freedesktop.org/patch/msgid/20230529223935.2672495-3-dmitry.osipenko@collabora.com
Link: https://patchwork.freedesktop.org/patch/msgid/20230529223935.2672495-4-dmitry.osipenko@collabora.com
Link: https://patchwork.freedesktop.org/patch/msgid/20230529223935.2672495-2-dmitry.osipenko@collabora.com
Link: https://patchwork.freedesktop.org/patch/msgid/20230529223935.2672495-3-dmitry.osipenko@collabora.com
Link: https://patchwork.freedesktop.org/patch/msgid/20230529223935.2672495-4-dmitry.osipenko@collabora.com

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 6bcf324..f9d4e22 100644 (file)
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -778,8 +778,6 @@ int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
 {
        struct drm_gem_object *obj = dma_buf->priv;
 
-       dma_resv_assert_held(dma_buf->resv);
-
        return drm_gem_prime_mmap(obj, vma);
 }
 EXPORT_SYMBOL(drm_gem_dmabuf_mmap);

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index fd556a0..1df74f7 100644 (file)
--- 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 3abc475..8e194db 100644 (file)
--- 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 dea3889..a402316 100644 (file)
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -694,8 +694,6 @@ 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;