pstore/zone: Introduce common layer to manage storage zones

Implement a common set of APIs needed to support pstore storage zones,
based on how ramoops is designed. This will be used by pstore/blk with
the intention of migrating pstore/ram in the future.

Signed-off-by: WeiXiong Liao <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]/
Co-developed-by: Kees Cook <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

Author: WeiXiong Liao

fs/pstore/Kconfig

@@ -153,3 +153,10 @@ config PSTORE_RAM
 	  "ramoops.ko".
 
 	  For more information, see Documentation/admin-guide/ramoops.rst.
+
+config PSTORE_ZONE
+	tristate
+	depends on PSTORE
+	help
+	  The common layer for pstore/blk (and pstore/ram in the future)
+	  to manage storage in zones.

fs/pstore/Makefile

@@ -12,3 +12,6 @@ pstore-$(CONFIG_PSTORE_PMSG)	+= pmsg.o
 
 ramoops-objs += ram.o ram_core.o
 obj-$(CONFIG_PSTORE_RAM)	+= ramoops.o
+
+pstore_zone-objs += zone.o
+obj-$(CONFIG_PSTORE_ZONE)	+= pstore_zone.o