Re: [PATCH v3 5/9] dma-buf: Move dma_buf_mmap_unlocked() to dynamic locking specification
From: Christian König via Virtualization <hidden>
Date: 2022-08-24 14:01:47
Also in:
amd-gfx, dri-devel, intel-gfx, linux-arm-msm, linux-media, linux-rdma, lkml
This should work, but I'm really wondering if this makes a difference for somebody. Anyway the approach is fine with me: Acked-by: Christian König [off-list ref] Regards, Christian. Am 24.08.22 um 12:22 schrieb Dmitry Osipenko:
quoted hunk
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);
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