vfs: make AIO use the proper rw_verify_area() area helpers

commit a70b52ec1aaeaf60f4739edb1b422827cb6f3893 upstream.

We had for some reason overlooked the AIO interface, and it didn't use
the proper rw_verify_area() helper function that checks (for example)
mandatory locking on the file, and that the size of the access doesn't
cause us to overflow the provided offset limits etc.

Instead, AIO did just the security_file_permission() thing (that
rw_verify_area() also does) directly.

This fixes it to do all the proper helper functions, which not only
means that now mandatory file locking works with AIO too, we can
actually remove lines of code.

Reported-by: Manish Honap <manish_honap_vit@yahoo.co.in>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert "tcp: cubic: fix bug in bictcp_acked()"

This reverts commit fdace809d645872eda413a4e37d2f292f3adb5ad.
Revert "tcp: cubic: fix overflow error in bictcp_update()"

This reverts commit 0c6c7f0b9d087156d8d2982ba8c9959d639593fa.
Revert " ashmem: avoid deadlock between read and mmap calls"

This reverts commit 0deef54a7024c31059099da4734f538e2888f242.