[PATCH v2 1/4] pstore/blk: Improve failure reporting

[Kees Cook]

There was no feedback on bad registration attempts. Add details on the
failure cause.

Signed-off-by: Kees Cook <keescook at chromium.org>
---
 fs/pstore/blk.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 4bb8a344957a..91d7a848c85b 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -114,8 +114,19 @@ static int __register_pstore_device(struct pstore_device_info *dev)
 
 	lockdep_assert_held(&pstore_blk_lock);
 
-	if (!dev || !dev->total_size || !dev->read || !dev->write)
+	if (!dev || !dev->total_size || !dev->read || !dev->write) {
+		if (!dev)
+			pr_err("NULL device info\n");
+		else {
+			if (!dev->total_size)
+				pr_err("zero sized device\n");
+			if (!dev->read)
+				pr_err("no read handler for device\n");
+			if (!dev->write)
+				pr_err("no write handler for device\n");
+		}
 		return -EINVAL;
+	}
 
 	/* someone already registered before */
 	if (pstore_zone_info)
-- 
2.25.1