[PATCH v1 3/7] Revert "udmabuf: Assert held reservation lock for dma-buf mmapping"

From: Dmitry Osipenko
Date: Sun Apr 02 2023 - 12:49:32 EST


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.

Fixes: aa3f99896443 ("udmabuf: Assert held reservation lock for dma-buf mmapping")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
---
drivers/dma-buf/udmabuf.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 740d6e426ee9..277f1afa9552 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -52,8 +52,6 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma)
{
struct udmabuf *ubuf = buf->priv;

- dma_resv_assert_held(buf->resv);
-
if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
return -EINVAL;

--
2.39.2