This patch removes dead code spotted by the Coverity checker.
Signed-off-by: Adrian Bunk <[email protected]>
---
drivers/scsi/qla4xxx/ql4_isr.c | 18 +-----------------
1 file changed, 1 insertion(+), 17 deletions(-)
--- linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c.old 2008-02-19 20:29:16.000000000 +0200
+++ linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c 2008-02-19 20:30:37.000000000 +0200
@@ -91,38 +91,22 @@ static void qla4xxx_status_entry(struct
if (scsi_status == 0) {
cmd->result = DID_OK << 16;
break;
}
if (sts_entry->iscsiFlags & ISCSI_FLAG_RESIDUAL_OVER) {
cmd->result = DID_ERROR << 16;
break;
}
- if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER) {
+ if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER)
scsi_set_resid(cmd, residual);
- if (!scsi_status && ((scsi_bufflen(cmd) - residual) <
- cmd->underflow)) {
-
- cmd->result = DID_ERROR << 16;
-
- DEBUG2(printk("scsi%ld:%d:%d:%d: %s: "
- "Mid-layer Data underrun0, "
- "xferlen = 0x%x, "
- "residual = 0x%x\n", ha->host_no,
- cmd->device->channel,
- cmd->device->id,
- cmd->device->lun, __func__,
- scsi_bufflen(cmd), residual));
- break;
- }
- }
cmd->result = DID_OK << 16 | scsi_status;
if (scsi_status != SCSI_CHECK_CONDITION)
break;
/* Copy Sense Data into sense buffer. */
memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
sensebytecnt = le16_to_cpu(sts_entry->senseDataByteCnt);
On Tue, 2008-02-19 at 21:29 +0200, Adrian Bunk wrote:
> This patch removes dead code spotted by the Coverity checker.
>
> Signed-off-by: Adrian Bunk <[email protected]>
>
> ---
>
> drivers/scsi/qla4xxx/ql4_isr.c | 18 +-----------------
> 1 file changed, 1 insertion(+), 17 deletions(-)
>
> --- linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c.old 2008-02-19 20:29:16.000000000 +0200
> +++ linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c 2008-02-19 20:30:37.000000000 +0200
> @@ -91,38 +91,22 @@ static void qla4xxx_status_entry(struct
> if (scsi_status == 0) {
> cmd->result = DID_OK << 16;
> break;
> }
>
> if (sts_entry->iscsiFlags & ISCSI_FLAG_RESIDUAL_OVER) {
> cmd->result = DID_ERROR << 16;
> break;
> }
>
> - if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER) {
> + if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER)
> scsi_set_resid(cmd, residual);
> - if (!scsi_status && ((scsi_bufflen(cmd) - residual) <
> - cmd->underflow)) {
> -
> - cmd->result = DID_ERROR << 16;
> -
> - DEBUG2(printk("scsi%ld:%d:%d:%d: %s: "
> - "Mid-layer Data underrun0, "
> - "xferlen = 0x%x, "
> - "residual = 0x%x\n", ha->host_no,
> - cmd->device->channel,
> - cmd->device->id,
> - cmd->device->lun, __func__,
> - scsi_bufflen(cmd), residual));
> - break;
> - }
> - }
This code doesn't look dead to me, it looks to be enforcing
cmd->underrun if set ... what makes the coverity checker think it can
never be executed?
James
On Tue, 19 Feb 2008, James Bottomley wrote:
> On Tue, 2008-02-19 at 21:29 +0200, Adrian Bunk wrote:
> > This patch removes dead code spotted by the Coverity checker.
> >
> > Signed-off-by: Adrian Bunk <[email protected]>
> >
> > ---
> >
> > drivers/scsi/qla4xxx/ql4_isr.c | 18 +-----------------
> > 1 file changed, 1 insertion(+), 17 deletions(-)
> >
> > --- linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c.old 2008-02-19 20:29:16.000000000 +0200
> > +++ linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c 2008-02-19 20:30:37.000000000 +0200
> > @@ -91,38 +91,22 @@ static void qla4xxx_status_entry(struct
> > if (scsi_status == 0) {
> > cmd->result = DID_OK << 16;
> > break;
> > }
> >
> > if (sts_entry->iscsiFlags & ISCSI_FLAG_RESIDUAL_OVER) {
> > cmd->result = DID_ERROR << 16;
> > break;
> > }
> >
> > - if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER) {
> > + if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER)
> > scsi_set_resid(cmd, residual);
> > - if (!scsi_status && ((scsi_bufflen(cmd) - residual) <
> > - cmd->underflow)) {
> > -
> > - cmd->result = DID_ERROR << 16;
> > -
> > - DEBUG2(printk("scsi%ld:%d:%d:%d: %s: "
> > - "Mid-layer Data underrun0, "
> > - "xferlen = 0x%x, "
> > - "residual = 0x%x\n", ha->host_no,
> > - cmd->device->channel,
> > - cmd->device->id,
> > - cmd->device->lun, __func__,
> > - scsi_bufflen(cmd), residual));
> > - break;
> > - }
> > - }
>
> This code doesn't look dead to me, it looks to be enforcing
> cmd->underrun if set ... what makes the coverity checker think it can
> never be executed?
Hmm, guess it's the earlier 'if (scsi_status == 0)' check a few lines
up... Dave S., can you take a look at this... Thanks, av
On Tue, 2008-02-19 at 18:35 -0800, Andrew Vasquez wrote:
> On Tue, 19 Feb 2008, James Bottomley wrote:
>
> > On Tue, 2008-02-19 at 21:29 +0200, Adrian Bunk wrote:
> > > This patch removes dead code spotted by the Coverity checker.
> > >
> > > Signed-off-by: Adrian Bunk <[email protected]>
> > >
> > > ---
> > >
> > > drivers/scsi/qla4xxx/ql4_isr.c | 18 +-----------------
> > > 1 file changed, 1 insertion(+), 17 deletions(-)
> > >
> > > --- linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c.old 2008-02-19 20:29:16.000000000 +0200
> > > +++ linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c 2008-02-19 20:30:37.000000000 +0200
> > > @@ -91,38 +91,22 @@ static void qla4xxx_status_entry(struct
> > > if (scsi_status == 0) {
> > > cmd->result = DID_OK << 16;
> > > break;
> > > }
> > >
> > > if (sts_entry->iscsiFlags & ISCSI_FLAG_RESIDUAL_OVER) {
> > > cmd->result = DID_ERROR << 16;
> > > break;
> > > }
> > >
> > > - if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER) {
> > > + if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER)
> > > scsi_set_resid(cmd, residual);
> > > - if (!scsi_status && ((scsi_bufflen(cmd) - residual) <
> > > - cmd->underflow)) {
> > > -
> > > - cmd->result = DID_ERROR << 16;
> > > -
> > > - DEBUG2(printk("scsi%ld:%d:%d:%d: %s: "
> > > - "Mid-layer Data underrun0, "
> > > - "xferlen = 0x%x, "
> > > - "residual = 0x%x\n", ha->host_no,
> > > - cmd->device->channel,
> > > - cmd->device->id,
> > > - cmd->device->lun, __func__,
> > > - scsi_bufflen(cmd), residual));
> > > - break;
> > > - }
> > > - }
> >
> > This code doesn't look dead to me, it looks to be enforcing
> > cmd->underrun if set ... what makes the coverity checker think it can
> > never be executed?
>
> Hmm, guess it's the earlier 'if (scsi_status == 0)' check a few lines
> up... Dave S., can you take a look at this... Thanks, av
Ah, so the !scsi_status is wrong it was supposed to be scsi_status !=
0 ... and even then it can just be dropped.
James
On Tue, 19 Feb 2008, James Bottomley wrote:
> On Tue, 2008-02-19 at 18:35 -0800, Andrew Vasquez wrote:
> > On Tue, 19 Feb 2008, James Bottomley wrote:
> >
> > > On Tue, 2008-02-19 at 21:29 +0200, Adrian Bunk wrote:
> > > > This patch removes dead code spotted by the Coverity checker.
> > > >
> > > > Signed-off-by: Adrian Bunk <[email protected]>
> > > >
> > > > ---
> > > >
> > > > drivers/scsi/qla4xxx/ql4_isr.c | 18 +-----------------
> > > > 1 file changed, 1 insertion(+), 17 deletions(-)
> > > >
> > > > --- linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c.old 2008-02-19 20:29:16.000000000 +0200
> > > > +++ linux-2.6/drivers/scsi/qla4xxx/ql4_isr.c 2008-02-19 20:30:37.000000000 +0200
> > > > @@ -91,38 +91,22 @@ static void qla4xxx_status_entry(struct
> > > > if (scsi_status == 0) {
> > > > cmd->result = DID_OK << 16;
> > > > break;
> > > > }
> > > >
> > > > if (sts_entry->iscsiFlags & ISCSI_FLAG_RESIDUAL_OVER) {
> > > > cmd->result = DID_ERROR << 16;
> > > > break;
> > > > }
> > > >
> > > > - if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER) {
> > > > + if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER)
> > > > scsi_set_resid(cmd, residual);
> > > > - if (!scsi_status && ((scsi_bufflen(cmd) - residual) <
> > > > - cmd->underflow)) {
> > > > -
> > > > - cmd->result = DID_ERROR << 16;
> > > > -
> > > > - DEBUG2(printk("scsi%ld:%d:%d:%d: %s: "
> > > > - "Mid-layer Data underrun0, "
> > > > - "xferlen = 0x%x, "
> > > > - "residual = 0x%x\n", ha->host_no,
> > > > - cmd->device->channel,
> > > > - cmd->device->id,
> > > > - cmd->device->lun, __func__,
> > > > - scsi_bufflen(cmd), residual));
> > > > - break;
> > > > - }
> > > > - }
> > >
> > > This code doesn't look dead to me, it looks to be enforcing
> > > cmd->underrun if set ... what makes the coverity checker think it can
> > > never be executed?
> >
> > Hmm, guess it's the earlier 'if (scsi_status == 0)' check a few lines
> > up... Dave S., can you take a look at this... Thanks, av
>
> Ah, so the !scsi_status is wrong it was supposed to be scsi_status !=
> 0 ... and even then it can just be dropped.
My guess is that the check should have been written as:
...
if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER)
scsi_set_resid(cmd, residual);
if ((scsi_bufflen(cmd) - residual) < cmd->underflow) {
...
It looks to be a logic-error while porting from qla2xxx, where
scsi_status during CS_COMPLETE is the full 16-bit status (high-byte is
transport, low-byte SCSI status) from from the FCP_RSP frame (not so
in iSCSI, where it's just the SCSI-status) and the residual check
in qla_isr.c::qla2x00_status_entry() looks like:
if (!lscsi_status &&
((unsigned)(scsi_bufflen(cp) - resid) <
cp->underflow)) {
...
I'll defer to Dave S. for verification.
Andrew Vasquez wrote:
<snip>
> > > Hmm, guess it's the earlier 'if (scsi_status == 0)' check
> a few lines
> > > up... Dave S., can you take a look at this... Thanks, av
> >
> > Ah, so the !scsi_status is wrong it was supposed to be
> scsi_status !=
> > 0 ... and even then it can just be dropped.
>
> My guess is that the check should have been written as:
>
> ...
> if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER)
> scsi_set_resid(cmd, residual);
> if ((scsi_bufflen(cmd) - residual) < cmd->underflow) {
> ...
>
> It looks to be a logic-error while porting from qla2xxx, where
> scsi_status during CS_COMPLETE is the full 16-bit status (high-byte is
> transport, low-byte SCSI status) from from the FCP_RSP frame (not so
> in iSCSI, where it's just the SCSI-status) and the residual check
> in qla_isr.c::qla2x00_status_entry() looks like:
>
> if (!lscsi_status &&
> ((unsigned)(scsi_bufflen(cp) - resid) <
> cp->underflow)) {
> ...
>
> I'll defer to Dave S. for verification.
>
The correct patch needs to be
Signed-off-by: David C Somayajulu <[email protected]>
---
diff --git a/drivers/scsi/qla4xxx/ql4_isr.c
b/drivers/scsi/qla4xxx/ql4_isr.c
index 0f029d0..fc84db4 100644
--- a/drivers/scsi/qla4xxx/ql4_isr.c
+++ b/drivers/scsi/qla4xxx/ql4_isr.c
@@ -100,8 +100,7 @@ static void qla4xxx_status_entry(struct
if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER) {
scsi_set_resid(cmd, residual);
- if (!scsi_status && ((scsi_bufflen(cmd) -
residual) <
- cmd->underflow)) {
+ if ((scsi_bufflen(cmd) - residual) <
cmd->underflow) {
cmd->result = DID_ERROR << 16;
> The correct patch needs to be
>
> Signed-off-by: David C Somayajulu <[email protected]>
>
> ---
>
> diff --git a/drivers/scsi/qla4xxx/ql4_isr.c
> b/drivers/scsi/qla4xxx/ql4_isr.c
> index 0f029d0..fc84db4 100644
> --- a/drivers/scsi/qla4xxx/ql4_isr.c
> +++ b/drivers/scsi/qla4xxx/ql4_isr.c
> @@ -100,8 +100,7 @@ static void qla4xxx_status_entry(struct
>
> if (sts_entry->iscsiFlags &ISCSI_FLAG_RESIDUAL_UNDER) {
> scsi_set_resid(cmd, residual);
> - if (!scsi_status && ((scsi_bufflen(cmd) -
> residual) <
> - cmd->underflow)) {
> + if ((scsi_bufflen(cmd) - residual) <
> cmd->underflow) {
The patch is line-wrapped and can' be applied.
Greetings,
Eike