Commit ceb7b62e authored by Huan Yang's avatar Huan Yang Committed by Vivek Kasireddy
Browse files

Revert "udmabuf: fix vmap_udmabuf error page set" 



This reverts commit 18d7de82.

We cannot use vmap_pfn() in vmap_udmabuf() as it would fail the pfn_valid()
check in vmap_pfn_apply(). This is because vmap_pfn() is intended to be
used for mapping non-struct-page memory such as PCIe BARs. Since, udmabuf
mostly works with pages/folios backed by shmem/hugetlbfs/THP, vmap_pfn()
is not the right tool or API to invoke for implementing vmap.

Signed-off-by: default avatarHuan Yang <link@vivo.com>
Suggested-by: default avatarVivek Kasireddy <vivek.kasireddy@intel.com>
Reported-by: default avatarBingbu Cao <bingbu.cao@linux.intel.com>
Closes: https://lore.kernel.org/dri-devel/eb7e0137-3508-4287-98c4-816c5fd98e10@vivo.com/T/#mbda4f64a3532b32e061f4e8763bc8e307bea3ca8


Acked-by: default avatarVivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: default avatarVivek Kasireddy <vivek.kasireddy@intel.com>
Link: https://lore.kernel.org/r/20250428073831.19942-2-link@vivo.com
parent 549810e9

drivers/dma-buf/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -36,7 +36,6 @@ config UDMABUF 
	depends on DMA_SHARED_BUFFER

	depends on MEMFD_CREATE || COMPILE_TEST

	depends on MMU

	select VMAP_PFN

	help

	  A driver to let userspace turn memfd regions into dma-bufs.

	  Qemu can use this to create host dmabufs for guest framebuffers.

drivers/dma-buf/udmabuf.c

+7 −15
Original line number Diff line number Diff line
@@ -109,29 +109,21 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma) 
static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)

{

	struct udmabuf *ubuf = buf->priv;

	unsigned long *pfns;

	struct page **pages;

	void *vaddr;

	pgoff_t pg;



	dma_resv_assert_held(buf->resv);



	/**

	 * HVO may free tail pages, so just use pfn to map each folio

	 * into vmalloc area.

	 */

	pfns = kvmalloc_array(ubuf->pagecount, sizeof(*pfns), GFP_KERNEL);

	if (!pfns)

	pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages), GFP_KERNEL);

	if (!pages)

		return -ENOMEM;



	for (pg = 0; pg < ubuf->pagecount; pg++) {

		unsigned long pfn = folio_pfn(ubuf->folios[pg]);



		pfn += ubuf->offsets[pg] >> PAGE_SHIFT;

		pfns[pg] = pfn;

	}

	for (pg = 0; pg < ubuf->pagecount; pg++)

		pages[pg] = &ubuf->folios[pg]->page;



	vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL);

	kvfree(pfns);

	vaddr = vm_map_ram(pages, ubuf->pagecount, -1);

	kvfree(pages);

	if (!vaddr)

		return -EINVAL;