pstore: Avoid duplicate call of persistent_ram_zap()

When initialing a prz, if invalid data is found (no PERSISTENT_RAM_SIG),
the function call path looks like this:

ramoops_init_prz ->
    persistent_ram_new -> persistent_ram_post_init -> persistent_ram_zap
    persistent_ram_zap

As we can see, persistent_ram_zap() is called twice.
We can avoid this by adding an option to persistent_ram_new(), and
only call persistent_ram_zap() when it is needed.

Signed-off-by: Peng Wang <wangpeng15@xiaomi.com>
[kees: minor tweak to exit path and commit log]
Signed-off-by: Kees Cook <keescook@chromium.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index 602d64725222..6e94980357d2 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -30,6 +30,7 @@
  * PRZ_FLAG_NO_LOCK is used. For all other cases, locking is required.
  */
 #define PRZ_FLAG_NO_LOCK	BIT(0)
+#define PRZ_FLAG_ZAP_OLD	BIT(1)
 
 struct persistent_ram_buffer;
 struct rs_control;