On Thu, Aug 25, 2016 at 1:23 AM, Tom Yan [off-list ref] wrote:

You only fill the bytes that you want to to set explicitly:

+       put_unaligned_le16(0x0002,  &sctpg[0]); /* SCT_ACT_WRITE_SAME */
+       put_unaligned_le16(0x0101,  &sctpg[1]); /* WRITE PTRN FG */
+       put_unaligned_le64(lba,     &sctpg[2]);
+       put_unaligned_le64(num,     &sctpg[6]);
+       put_unaligned_le32(0u,      &sctpg[10]);

What I doubted is, if you don't memset (zero-fill) the buffer first,
will other bytes have indeterministic value that causes random
unexpected behavior?

No.
If there is random or unexpected behaviour the device is broken
and some other remedy, such as blacklisting, is required.

---
Shaun