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    Subject[PATCH 20/52] Limit number of pages returned by direct_access()
    Date
    Truncate number of pages mapped by direct_access() to remain with-in window
    size. User might request mapping pages beyond window size.

    Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
    ---
    fs/fuse/virtio_fs.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
    index e4d5e0cd41ba..ef1469b38a6d 100644
    --- a/fs/fuse/virtio_fs.c
    +++ b/fs/fuse/virtio_fs.c
    @@ -449,13 +449,14 @@ static long virtio_fs_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
    {
    struct virtio_fs *fs = dax_get_private(dax_dev);
    phys_addr_t offset = PFN_PHYS(pgoff);
    + size_t max_nr_pages = fs->window_len/PAGE_SIZE - pgoff;

    if (kaddr)
    *kaddr = fs->window_kaddr + offset;
    if (pfn)
    *pfn = phys_to_pfn_t(fs->window_phys_addr + offset,
    PFN_DEV | PFN_MAP);
    - return nr_pages;
    + return nr_pages > max_nr_pages ? max_nr_pages : nr_pages;
    }

    static size_t virtio_fs_copy_from_iter(struct dax_device *dax_dev,
    --
    2.13.6
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