2023-04-02 16:51:02

by Dmitry Osipenko

[permalink] [raw]
Subject: [PATCH v1 4/7] Revert "fastrpc: 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, it's solved
by moving the lock down to exporters.

Fixes: 265751a513ad ("fastrpc: Assert held reservation lock for dma-buf mmapping")
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/misc/fastrpc.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index a701132638cf..7e9c9ad37fd9 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -6,7 +6,6 @@
#include <linux/device.h>
#include <linux/dma-buf.h>
#include <linux/dma-mapping.h>
-#include <linux/dma-resv.h>
#include <linux/idr.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
@@ -733,8 +732,6 @@ static int fastrpc_mmap(struct dma_buf *dmabuf,
struct fastrpc_buf *buf = dmabuf->priv;
size_t size = vma->vm_end - vma->vm_start;

- dma_resv_assert_held(dmabuf->resv);
-
return dma_mmap_coherent(buf->dev, vma, buf->virt,
FASTRPC_PHYS(buf->phys), size);
}
--
2.39.2