6.12-stable review patch. If anyone has any objections, please let me know.
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From: Huan Yang link@vivo.com
[ Upstream commit ceb7b62eaaaacfcf87473bd2e99ac73a758620cb ]
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.... 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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma-buf/Kconfig | 1 - drivers/dma-buf/udmabuf.c | 22 +++++++--------------- 2 files changed, 7 insertions(+), 16 deletions(-)
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index fee04fdb08220..b46eb8a552d7b 100644 --- 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 959f690b12260..0e127a9109e75 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -74,29 +74,21 @@ 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;