Commit 18d7de82 authored by Huan Yang's avatar Huan Yang Committed by Vivek Kasireddy
Browse files

udmabuf: fix vmap_udmabuf error page set 



Currently vmap_udmabuf set page's array by each folio.
But, ubuf->folios is only contain's the folio's head page.

That mean we repeatedly mapped the folio head page to the vmalloc area.

Due to udmabuf can use hugetlb, if HVO enabled, tail page may not exist,
so, we can't use page array to map, instead, use pfn array.

By this, we removed page usage in udmabuf totally.

Fixes: 5e72b2b4 ("udmabuf: convert udmabuf driver to use folios")
Suggested-by: default avatarVivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: default avatarHuan Yang <link@vivo.com>
Acked-by: default avatarVivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: default avatarVivek Kasireddy <vivek.kasireddy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240918025238.2957823-4-link@vivo.com
parent 1c0844c6

drivers/dma-buf/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 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

+15 −7
Original line number Diff line number Diff line
@@ -103,21 +103,29 @@ 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;

	struct page **pages;

	unsigned long *pfns;

	void *vaddr;

	pgoff_t pg;



	dma_resv_assert_held(buf->resv);



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

	if (!pages)

	/**

	 * 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)

		return -ENOMEM;



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

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

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

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



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

		pfns[pg] = pfn;

	}



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

	kvfree(pages);

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

	kvfree(pfns);

	if (!vaddr)

		return -EINVAL;