pstore: Introduce new argument 'compressed' in the read callback

Backends will set the flag 'compressed' after reading the log from
persistent store to indicate the data being returned to pstore is
compressed or not.

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index abfca4f..abd437d 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -55,7 +55,7 @@
 	int		(*close)(struct pstore_info *psi);
 	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
 			int *count, struct timespec *time, char **buf,
-			struct pstore_info *psi);
+			bool *compressed, struct pstore_info *psi);
 	int		(*write)(enum pstore_type_id type,
 			enum kmsg_dump_reason reason, u64 *id,
 			unsigned int part, int count, bool compressed,