[PATCH v3 5/9] dma-buf: Move dma_buf_mmap_unlocked() to dynamic locking specification

Dmitry Osipenko
2022-08-24T10:24:22Z

Move dma_buf_mmap_unlocked() function to the dynamic locking specification
by taking the reservation lock. Neither of the today's drivers take the
reservation lock within the mmap() callback, hence it's safe to enforce
the locking.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
drivers/dma-buf/dma-buf.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index f358af401360..4556a12bd741 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1348,6 +1348,8 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF);
int dma_buf_mmap_unlocked(struct dma_buf *dmabuf, struct vm_area_struct *vma,
unsigned long pgoff)
{
+ int ret;
+
if (WARN_ON(!dmabuf || !vma))
return -EINVAL;

@@ -1368,7 +1370,11 @@ int dma_buf_mmap_unlocked(struct dma_buf *dmabuf, struct vm_area_struct *vma,
vma_set_file(vma, dmabuf->file);
vma->vm_pgoff = pgoff;

- return dmabuf->ops->mmap(dmabuf, vma);
+ dma_resv_lock(dmabuf->resv, NULL);
+ ret = dmabuf->ops->mmap(dmabuf, vma);
+ dma_resv_unlock(dmabuf->resv);
+
+ return ret;
}
EXPORT_SYMBOL_NS_GPL(dma_buf_mmap_unlocked, DMA_BUF);

--
2.37.2