| Message ID | 20240822084342.1574914-4-link@vivo.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | udmbuf bug fix and some improvements | expand |
Hi Huan, > Subject: [PATCH v4 3/5] 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. > > Suggested-by: Vivek Kasireddy <vivek.kasireddy@intel.com> > Signed-off-by: Huan Yang <link@vivo.com> > --- > drivers/dma-buf/Kconfig | 1 + > drivers/dma-buf/udmabuf.c | 22 +++++++++++++++------- > 2 files changed, 16 insertions(+), 7 deletions(-) > > diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig > index b46eb8a552d7..fee04fdb0822 100644 > --- a/drivers/dma-buf/Kconfig > +++ b/drivers/dma-buf/Kconfig > @@ -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. > diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c > index 1bad4576d492..0bbc9df36c0a 100644 > --- a/drivers/dma-buf/udmabuf.c > +++ b/drivers/dma-buf/udmabuf.c > @@ -96,21 +96,29 @@ 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]); > > - vaddr = vm_map_ram(pages, ubuf->pagecount, -1); > - kvfree(pages); > + pfn += ubuf->offsets[pg] >> PAGE_SHIFT; > + pfns[pg] = pfn; > + } > + > + vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL); > + kvfree(pfns); Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com> > if (!vaddr) > return -EINVAL; > > -- > 2.45.2
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index b46eb8a552d7..fee04fdb0822 100644 --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -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. diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 1bad4576d492..0bbc9df36c0a 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -96,21 +96,29 @@ 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]); - vaddr = vm_map_ram(pages, ubuf->pagecount, -1); - kvfree(pages); + pfn += ubuf->offsets[pg] >> PAGE_SHIFT; + pfns[pg] = pfn; + } + + vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL); + kvfree(pfns); if (!vaddr) return -EINVAL;
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. Suggested-by: Vivek Kasireddy <vivek.kasireddy@intel.com> Signed-off-by: Huan Yang <link@vivo.com> --- drivers/dma-buf/Kconfig | 1 + drivers/dma-buf/udmabuf.c | 22 +++++++++++++++------- 2 files changed, 16 insertions(+), 7 deletions(-)