> -----Original Message----- > From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi- > owner@xxxxxxxxxxxxxxx] On Behalf Of Christoph Hellwig > Sent: Sunday, 29 June, 2014 8:35 AM > To: James Bottomley > Cc: Martin K. Petersen; linux-scsi@xxxxxxxxxxxxxxx > Subject: [PATCH 06/10] sd: don't use scsi_setup_blk_pc_cmnd for discard > requests > > Simplify handling of discard requests by setting up the command directly > instead of initializing request fields and then calling > scsi_setup_blk_pc_cmnd to propagate the information into the command. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > --- > drivers/scsi/sd.c | 43 ++++++++++++++++++++++++------------------- > 1 file changed, 24 insertions(+), 19 deletions(-) > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 25f25dd..9737e78 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -691,8 +691,10 @@ static void sd_config_discard(struct scsi_disk *sdkp, > unsigned int mode) > * Will issue either UNMAP or WRITE SAME(16) depending on preference > * indicated by target device. > **/ > -static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request > *rq) > +static int sd_setup_discard_cmnd(struct scsi_cmnd *cmd) > { > + struct request *rq = cmd->request; > + struct scsi_device *sdp = cmd->device; > struct scsi_disk *sdkp = scsi_disk(rq->rq_disk); > sector_t sector = blk_rq_pos(rq); > unsigned int nr_sectors = blk_rq_sectors(rq); > @@ -704,9 +706,6 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, > struct request *rq) > > sector >>= ilog2(sdp->sector_size) - 9; > nr_sectors >>= ilog2(sdp->sector_size) - 9; > - rq->timeout = SD_TIMEOUT; > - > - memset(rq->cmd, 0, rq->cmd_len); Is *cmd guaranteed to be zero at this point? With scsi-mq.2 I've seen UNMAP CDBs with garbage in CDB bytes 2 to 5 (which causes a drive that checks reserved fields to reject the command), which suggests there is a case in which that is not guaranteed. [ 295.280838] sd 0:0:0:0: [sda] Done: scmd ffff88042b564770 SUCCESS (0x1) [ 295.283368] sd 0:0:0:0: [sda] Result: hostbyte=DID_TARGET_FAILURE driverbyte=DRIVER_OK [ 295.286652] Unmap/Read sub-channel [ 295.287823] sd 0:0:0:0: [sda] scmd ffff88042b564770 CDB: 42 00 09 6a ed 10 00 00 18 00 [ 295.290696] sd 0:0:0:0: [sda] Sense Key : Illegal Request [current] [ 295.293621] sd 0:0:0:0: [sda] Add. Sense: Invalid field in cdb [ 295.296206] sd 0:0:0:0: [sda] scmd ffff88042b564770 Discard failure result DID_OK DRIVER_SENSE [ 295.299296] sd 0:0:0:0: [sda] Sense Key : Illegal Request [current] [ 295.302104] sd 0:0:0:0: [sda] Add. Sense: Invalid field in cdb [ 295.304719] Unmap/Read sub-channel [ 295.305829] sd 0:0:0:0: [sda] scmd ffff88042b564770 CDB: 42 00 09 6a ed 10 00 00 18 00 [ 295.308777] end_request: critical target error, dev sda, sector 385875968 If so, then getting rid of the double memset is another benefit, and removing it from scsi_setup_fs_cmnd would be good too. Since that function is EXPORTED, does that prevent removing its memset? --- Rob Elliott HP Server Storage -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
