This patch converts all call sites of get_user_pages to use put_user_page*() instead of put_page*() functions to release reference to gup pinned pages. This is a bunch of trivial conversions which is a part of an effort by John Hubbard to solve issues with gup pinned pages and filesystem writeback. The issue is more clearly described in John Hubbard's patch[1] where put_user_page*() functions are introduced. Currently put_user_page*() simply does put_page but future implementations look to change that once treewide change of put_page callsites to put_user_page*() is finished. The lwn article describing the issue with gup pinned pages and filesystem writeback [2]. This patch has been tested by building and booting the kernel as I don't have the required hardware to test the device drivers. I did not modify gpu/drm drivers which use release_pages instead of put_page() to release reference of gup pinned pages as I am not clear whether release_pages and put_page are interchangable. [1] https://lkml.org/lkml/2019/3/26/1396 [2] https://lwn.net/Articles/784574/ Signed-off-by: Bharath Vedartham <linux.bhar@xxxxxxxxx> --- drivers/media/v4l2-core/videobuf-dma-sg.c | 3 +-- drivers/misc/sgi-gru/grufault.c | 2 +- drivers/staging/kpc2000/kpc_dma/fileops.c | 4 +--- drivers/vfio/vfio_iommu_type1.c | 2 +- fs/io_uring.c | 7 +++---- mm/gup_benchmark.c | 6 +----- net/xdp/xdp_umem.c | 7 +------ 7 files changed, 9 insertions(+), 22 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c index 66a6c6c..d6eeb43 100644 --- a/drivers/media/v4l2-core/videobuf-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c @@ -349,8 +349,7 @@ int videobuf_dma_free(struct videobuf_dmabuf *dma) BUG_ON(dma->sglen); if (dma->pages) { - for (i = 0; i < dma->nr_pages; i++) - put_page(dma->pages[i]); + put_user_pages(dma->pages, dma->nr_pages); kfree(dma->pages); dma->pages = NULL; } diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c index 4b713a8..61b3447 100644 --- a/drivers/misc/sgi-gru/grufault.c +++ b/drivers/misc/sgi-gru/grufault.c @@ -188,7 +188,7 @@ static int non_atomic_pte_lookup(struct vm_area_struct *vma, if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= 0) return -EFAULT; *paddr = page_to_phys(page); - put_page(page); + put_user_page(page); return 0; } diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c index 6166587..26dceed 100644 --- a/drivers/staging/kpc2000/kpc_dma/fileops.c +++ b/drivers/staging/kpc2000/kpc_dma/fileops.c @@ -198,9 +198,7 @@ int kpc_dma_transfer(struct dev_private_data *priv, struct kiocb *kcb, unsigned sg_free_table(&acd->sgt); err_dma_map_sg: err_alloc_sg_table: - for (i = 0 ; i < acd->page_count ; i++){ - put_page(acd->user_pages[i]); - } + put_user_pages(acd->user_pages, acd->page_count); err_get_user_pages: kfree(acd->user_pages); err_alloc_userpages: diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index add34ad..c491524 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -369,7 +369,7 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, */ if (ret > 0 && vma_is_fsdax(vmas[0])) { ret = -EOPNOTSUPP; - put_page(page[0]); + put_user_page(page[0]); } } up_read(&mm->mmap_sem); diff --git a/fs/io_uring.c b/fs/io_uring.c index 4ef62a4..b4a4549 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2694,10 +2694,9 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg, * if we did partial map, or found file backed vmas, * release any pages we did get */ - if (pret > 0) { - for (j = 0; j < pret; j++) - put_page(pages[j]); - } + if (pret > 0) + put_user_pages(pages, pret); + if (ctx->account_mem) io_unaccount_mem(ctx->user, nr_pages); kvfree(imu->bvec); diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c index 7dd602d..15fc7a2 100644 --- a/mm/gup_benchmark.c +++ b/mm/gup_benchmark.c @@ -76,11 +76,7 @@ static int __gup_benchmark_ioctl(unsigned int cmd, gup->size = addr - gup->addr; start_time = ktime_get(); - for (i = 0; i < nr_pages; i++) { - if (!pages[i]) - break; - put_page(pages[i]); - } + put_user_pages(pages, nr_pages); end_time = ktime_get(); gup->put_delta_usec = ktime_us_delta(end_time, start_time); diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index 9c6de4f..6103e19 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -173,12 +173,7 @@ static void xdp_umem_unpin_pages(struct xdp_umem *umem) { unsigned int i; - for (i = 0; i < umem->npgs; i++) { - struct page *page = umem->pgs[i]; - - set_page_dirty_lock(page); - put_page(page); - } + put_user_pages_dirty_lock(umem->pgs, umem->npgs); kfree(umem->pgs); umem->pgs = NULL; -- 1.8.3.1
