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? On 25 August 2016 at 06:04, Shaun Tancheff <shaun@xxxxxxxxxxxx> wrote: > On Wed, Aug 24, 2016 at 1:10 AM, Tom Yan <tom.ty89@xxxxxxxxx> wrote: >> Btw, I wonder if you need to memset your buffer with 0 first, like >> what is done in ata_scsi_rbuf_get. > > It is not necessary as the defined buffer is completely filled out here. > > Are you thinking as a sort of future proofing? > Ex: In the unlikely event that the SCT Write Same command > descriptor is expanded in a future ACS? > > It is more likely to see the command deprecated and replaced with a > new SCT feature. > > Regardless of how unlikely I would consider a memset here to clear > the remainder of the payload. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
