diff mbox

[4/4] drm/i915: Use CPU mapping for userspace dma-buf mmap()

Message ID 1439422160-20148-5-git-send-email-tiago.vignatti@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Tiago Vignatti Aug. 12, 2015, 11:29 p.m. UTC
Userspace is the one in charge of flush CPU by wrapping mmap with
begin{,end}_cpu_access.

v2: Remove LLC check cause we have dma-buf sync providers now. Also, fix return
before transferring ownership when mmap fails.
v3: Fix return values.
v4: !obj->base.filp is user triggerable, so removed the WARN_ON.

Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_dmabuf.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

Comments

Chris Wilson Aug. 23, 2015, 12:21 p.m. UTC | #1
On Wed, Aug 12, 2015 at 08:29:13PM -0300, Tiago Vignatti wrote:
> Userspace is the one in charge of flush CPU by wrapping mmap with
> begin{,end}_cpu_access.
> 
> v2: Remove LLC check cause we have dma-buf sync providers now. Also, fix return
> before transferring ownership when mmap fails.
> v3: Fix return values.
> v4: !obj->base.filp is user triggerable, so removed the WARN_ON.
> 
> Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com>

I have some reservations with CPU mmapping on !llc platforms, somehow we
need to encourage creation of snooped bo (and proper usage thereof).

However, the patches look good.
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index 8447ba4..ecd00d6 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -193,7 +193,23 @@  static void i915_gem_dmabuf_kunmap(struct dma_buf *dma_buf, unsigned long page_n
 
 static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
 {
-	return -EINVAL;
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+	int ret;
+
+	if (obj->base.size < vma->vm_end - vma->vm_start)
+		return -EINVAL;
+
+	if (!obj->base.filp)
+		return -ENODEV;
+
+	ret = obj->base.filp->f_op->mmap(obj->base.filp, vma);
+	if (ret)
+		return ret;
+
+	fput(vma->vm_file);
+	vma->vm_file = get_file(obj->base.filp);
+
+	return 0;
 }
 
 static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t length, enum dma_data_direction direction)