Commit 30b5144c authored by Dmitry Osipenko's avatar Dmitry Osipenko
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dma-buf/heaps: Don't 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 once these
drivers are moved to use reservation lock universally. The problem
solved by moving the lock down to exporters. This patch prepares dma-buf
heaps for the locking policy update.

Reviewed-by: default avatarEmil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230529223935.2672495-3-dmitry.osipenko@collabora.com
parent 6f508c88

drivers/dma-buf/heaps/cma_heap.c

+0 −3
Original line number Diff line number Diff line
@@ -13,7 +13,6 @@ 
#include <linux/dma-buf.h>

#include <linux/dma-heap.h>

#include <linux/dma-map-ops.h>

#include <linux/dma-resv.h>

#include <linux/err.h>

#include <linux/highmem.h>

#include <linux/io.h>
@@ -183,8 +182,6 @@ static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) 
{

	struct cma_heap_buffer *buffer = dmabuf->priv;



	dma_resv_assert_held(dmabuf->resv);



	if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)

		return -EINVAL;

drivers/dma-buf/heaps/system_heap.c

+0 −3
Original line number Diff line number Diff line
@@ -13,7 +13,6 @@ 
#include <linux/dma-buf.h>

#include <linux/dma-mapping.h>

#include <linux/dma-heap.h>

#include <linux/dma-resv.h>

#include <linux/err.h>

#include <linux/highmem.h>

#include <linux/mm.h>
@@ -201,8 +200,6 @@ static int system_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) 
	struct sg_page_iter piter;

	int ret;



	dma_resv_assert_held(dmabuf->resv);



	for_each_sgtable_page(table, &piter, vma->vm_pgoff) {

		struct page *page = sg_page_iter_page(&piter);