On Wed, 2022-01-05 at 16:48 +0800, Wenchao Hao wrote:
> On 2022/1/5 15:39, Damien Le Moal wrote:
> > On Wed, 2022-01-05 at 15:27 -0500, Wenchao Hao wrote:
> > > This is just a clean code. Since each branch of "if" state would check
> > > scmd->cmd_len, so move the check of scmd->cmd_len out of "if" state to
> > > simplify input parameters check.
> > >
> > > And remove redundant init of xlat_func at hand
> > >
> > > The patch do not change origin function logic.
> > >
> > > Signed-off-by: Wenchao Hao <haowenchao@xxxxxxxxxx>
> > > ---
> > > drivers/ata/libata-scsi.c | 9 ++++-----
> > > 1 file changed, 4 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> > > index 313e9475507b..ab8a2833dfec 100644
> > > --- a/drivers/ata/libata-scsi.c
> > > +++ b/drivers/ata/libata-scsi.c
> > > @@ -4023,16 +4023,15 @@ int __ata_scsi_queuecmd(struct scsi_cmnd *scmd, struct ata_device *dev)
> > > ata_xlat_func_t xlat_func;
> > > int rc = 0;
> > >
> > > + if (unlikely(!scmd->cmd_len))
> > > + goto bad_cdb_len;
> > > +
> > > if (dev->class == ATA_DEV_ATA || dev->class == ATA_DEV_ZAC) {
> > > - if (unlikely(!scmd->cmd_len || scmd->cmd_len > dev->cdb_len))
> > > + if (unlikely(scmd->cmd_len > dev->cdb_len))
> > > goto bad_cdb_len;
> > >
> > > xlat_func = ata_get_xlat_func(dev, scsi_op);
> > > } else {
> > > - if (unlikely(!scmd->cmd_len))
> > > - goto bad_cdb_len;
> > > -
> > > - xlat_func = NULL;
> > > if (likely((scsi_op != ATA_16) || !atapi_passthru16)) {
> > > /* relay SCSI command to ATAPI device */
> > > int len = COMMAND_SIZE(scsi_op);
> >
> > Did you miss my reply ?
> > This change is OK, but while at it, let's cleanup this function further.
> > I suggested something like this, which includes your changes.
> >
>
> Maybe I misunderstood your previous reply. I think you ask me to change
> prefix.
Yes, I asked that too. It is OK now.
>
> > diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> > index a16ef0030667..ed8be585a98f 100644
> > --- a/drivers/ata/libata-scsi.c
> > +++ b/drivers/ata/libata-scsi.c
> > @@ -3958,42 +3958,39 @@ int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
> > struct ata_device *dev)
> > {
> > u8 scsi_op = scmd->cmnd[0];
> > ata_xlat_func_t xlat_func;
> > - int rc = 0;
> > +
> > + if (unlikely(!scmd->cmd_len))
> > + goto bad_cdb_len;
> >
> > if (dev->class == ATA_DEV_ATA || dev->class == ATA_DEV_ZAC) {
> > - if (unlikely(!scmd->cmd_len || scmd->cmd_len > dev->cdb_len))
> > + if (unlikely(scmd->cmd_len > dev->cdb_len))
> > goto bad_cdb_len;
> >
> > xlat_func = ata_get_xlat_func(dev, scsi_op);
> > - } else {
> > - if (unlikely(!scmd->cmd_len))
> > - goto bad_cdb_len;
> > + } else if (scsi_op != ATA_16 || !atapi_passthru16) {
> > + /* relay SCSI command to ATAPI device */
> > + int len = COMMAND_SIZE(scsi_op);
> >
> > - xlat_func = NULL;
> > - if (likely((scsi_op != ATA_16) || !atapi_passthru16)) {
> > - /* relay SCSI command to ATAPI device */
> > - int len = COMMAND_SIZE(scsi_op);
> > - if (unlikely(len > scmd->cmd_len ||
> > - len > dev->cdb_len ||
> > - scmd->cmd_len > ATAPI_CDB_LEN))
> > - goto bad_cdb_len;
> > + if (unlikely(len > scmd->cmd_len ||
> > + len > dev->cdb_len ||
> > + scmd->cmd_len > ATAPI_CDB_LEN))
> > + goto bad_cdb_len;
> >
> > - xlat_func = atapi_xlat;
> > - } else {
> > - /* ATA_16 passthru, treat as an ATA command */
> > - if (unlikely(scmd->cmd_len > 16))
> > - goto bad_cdb_len;
> > + xlat_func = atapi_xlat;
> > + } else {
> > + /* ATA_16 passthru, treat as an ATA command */
> > + if (unlikely(scmd->cmd_len > 16))
> > + goto bad_cdb_len;
> >
> > - xlat_func = ata_get_xlat_func(dev, scsi_op);
> > - }
> > + xlat_func = ata_get_xlat_func(dev, scsi_op);
> > }
> >
> > if (xlat_func)
> > - rc = ata_scsi_translate(dev, scmd, xlat_func);
> > - else
> > - ata_scsi_simulate(dev, scmd);
> > + return ata_scsi_translate(dev, scmd, xlat_func);
> >
> > - return rc;
> > + ata_scsi_simulate(dev, scmd);
> > +
> > + return 0;
> >
> > bad_cdb_len:
> > scmd->result = DID_ERROR << 16;
> >
> > Do you see any problem with this change ?
> >
>
> This change looks good to me. Should I include this change in next
> patch? Or you would do this by youself?
Just include the change in your v3, that's fine. But test please. I did test
what I proposed and it worked fine but I prefer more tests.
And given that the patch does more that just changing the command checks, maybe
change the patch title to something like:
ata: libata-scsi: simplify __ata_scsi_queuecmd()
--
Damien Le Moal
Western Digital Research
