Revert "udmabuf: fix vmap_udmabuf error page set"

This reverts commit 18d7de823b7150344d242c3677e65d68c5271b04.

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: Huan Yang <link@vivo.com>
Suggested-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Reported-by: Bingbu Cao <bingbu.cao@linux.intel.com>
Closes: https://lore.kernel.org/dri-devel/eb7e0137-3508-4287-98c4-816c5fd98e10@vivo.com/T/#mbda4f64a3532b32e061f4e8763bc8e307bea3ca8
Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Link: https://lore.kernel.org/r/20250428073831.19942-2-link@vivo.com

diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index fee04fdb08220c1ea745bdf56802a0d1d9b231a5..b46eb8a552d7be02cb305f65aaf4ba168f03fee2 100644 (file)
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -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.

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 7eee3eb47a8ee8270231bc2d7fb1701df191a5d9..79845565089da17cca3a9195260dfe9ae66f91f5 100644 (file)
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -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;