Pull pstore changes from Tony Luck:
"A big part of this is the addition of compression to the generic
pstore layer so that all backends can use the pitiful amounts of
storage they control more effectively. Three other small
fixes/cleanups too.
* tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
pstore/ram: (really) fix undefined usage of rounddown_pow_of_two
pstore/ram: Read and write to the 'compressed' flag of pstore
efi-pstore: Read and write to the 'compressed' flag of pstore
erst: Read and write to the 'compressed' flag of pstore
powerpc/pseries: Read and write to the 'compressed' flag of pstore
pstore: Add file extension to pstore file if compressed
pstore: Add decompression support to pstore
pstore: Introduce new argument 'compressed' in the read callback
pstore: Add compression support to pstore
pstore/Kconfig: Select ZLIB_DEFLATE and ZLIB_INFLATE when PSTORE is selected
pstore: Add new argument 'compressed' in pstore write callback
powerpc/pseries: Remove (de)compression in nvram with pstore enabled
pstore: d_alloc_name() doesn't return an ERR_PTR
acpi/apei/erst: Add missing iounmap() on error in erst_exec_move_data()