From: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> Subject: mm: mmap: increase sockets maximum memory size pgoff for 32bits The AF_XDP sockets umem mapping interface uses XDP_UMEM_PGOFF_FILL_RING and XDP_UMEM_PGOFF_COMPLETION_RING offsets. These offsets are established already and are part of the configuration interface. But for 32-bit systems, using AF_XDP socket configuration, these values are too large to pass the maximum allowed file size verification. The offsets can be tuned off, but instead of changing the existing interface, let's extend the max allowed file size for sockets. No one has been using this until this patch with 32 bits as without this fix af_xdp sockets can't be used at all, so it unblocks af_xdp socket usage for 32bit systems. All list of mmap cbs for sockets was verified for side effects and all of them contain dummy cb - sock_no_mmap() at this moment, except the following: xsk_mmap() - it's what this fix is needed for. tcp_mmap() - doesn't have obvious issues with pgoff - no any references on it. packet_mmap() - return -EINVAL if it's even set. Link: http://lkml.kernel.org/r/20190812124326.32146-1-ivan.khoronzhuk@xxxxxxxxxx Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Björn Töpel <bjorn.topel@xxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Magnus Karlsson <magnus.karlsson@xxxxxxxxx> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Cc: David Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mmap.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/mmap.c~mm-mmap-increase-sockets-maximum-memory-size-pgoff-for-32bits +++ a/mm/mmap.c @@ -1358,6 +1358,9 @@ static inline u64 file_mmap_size_max(str 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; _
