Pull more s390 updates from Vasily Gorbik:

 - Fix three kasan findings

 - Add PERF_EVENT_IOC_PERIOD ioctl support

 - Add Crypto Express7S support and extend sysfs attributes for pkey

 - Minor common I/O layer documentation corrections

* tag 's390-5.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/cio: exclude subchannels with no parent from pseudo check
  s390/cio: avoid calling strlen on null pointer
  s390/topology: avoid firing events before kobjs are created
  s390/cpumf: Remove mixed white space
  s390/cpum_sf: Support ioctl PERF_EVENT_IOC_PERIOD
  s390/zcrypt: CEX7S exploitation support
  s390/cio: fix intparm documentation
  s390/pkey: Add sysfs attributes to emit AES CIPHER key blobs