Add file_pos field to bpf_sysctl context to read and write sysctl file
position at which sysctl is being accessed (read or written).
The field can be used to e.g. override whole sysctl value on write to
sysctl even when sys_write is called by user space with file_pos > 0. Or
BPF program may reject such accesses.
Change-Id: Ia2674d14b24b99c5081522f8b3025c52f6228bfa
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
b45b87b444