pstore: Allocate compression during late_initcall()

ramoops's call of pstore_register() was recently moved to run during
late_initcall() because the crypto backend may not have been ready during
postcore_initcall(). This meant early-boot crash dumps were not getting
caught by pstore any more.

Instead, lets allow calls to pstore_register() earlier, and once crypto
is ready we can initialize the compression.
Reported-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Fixes: cb3bee03 ("pstore: Use crypto compress API")
[kees: trivial rebase]
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Guenter Roeck <groeck@chromium.org>

fs/pstore/platform.c

@@ -786,13 +786,21 @@ static int __init pstore_init(void)
 
 	pstore_choose_compression();
 
+	/*
+	 * Check if any pstore backends registered earlier but did not
+	 * initialize compression because crypto was not ready. If so,
+	 * initialize compression now.
+	 */
+	if (psinfo && !tfm)
+		allocate_buf_for_compression();
+
 	ret = pstore_init_fs();
 	if (ret)
 		return ret;
 
 	return 0;
 }
-module_init(pstore_init)
+late_initcall(pstore_init);
 
 static void __exit pstore_exit(void)
 {

fs/pstore/ram.c

@@ -940,7 +940,7 @@ static int __init ramoops_init(void)
 	ramoops_register_dummy();
 	return platform_driver_register(&ramoops_driver);
 }
-late_initcall(ramoops_init);
+postcore_initcall(ramoops_init);
 
 static void __exit ramoops_exit(void)
 {