Re: [PATCH v2 bpf-next] mm: mmap: increase sockets maximum memory size pgoff for 32bits

[Daniel Borkmann]

On 8/12/19 2:43 PM, Ivan Khoronzhuk wrote:
> The AF_XDP sockets umem mapping interface uses XDP_UMEM_PGOFF_FILL_RING
> and XDP_UMEM_PGOFF_COMPLETION_RING offsets. The offsets seems like are
> established already and are part of configuration interface.
>
> But for 32-bit systems, while AF_XDP socket configuration, the values
> are to large to pass maximum allowed file size verification.
> The offsets can be tuned ofc, but instead of changing existent
> interface - extend max allowed file size for sockets.
>
> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
> ---
>
> Based on bpf-next/master

This is mainly for Andrew to pick rather than bpf-next, but I presume it would
apply cleanly to his tree as well.

> v2..v1:
> 	removed not necessarily #ifdev as ULL and UL for 64 has same size
>
>   mm/mmap.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 7e8c3e8ae75f..578f52812361 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1358,6 +1358,9 @@ static inline u64 file_mmap_size_max(struct file *file, struct inode *inode)
>   	if (S_ISBLK(inode->i_mode))
>   		return MAX_LFS_FILESIZE;
>   
> +	if (S_ISSOCK(inode->i_mode))
> +		return MAX_LFS_FILESIZE;
> +
>   	/* Special "we do even unsigned file positions" case */
>   	if (file->f_mode & FMODE_UNSIGNED_OFFSET)
>   		return 0;