[PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Nathan Chancellor]

clang warns:

drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
        case IBMVSCSI_HOST_ACTION_NONE:
             ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
here
        if (rc) {
            ^~

Initialize rc to zero so that the atomic_set and dev_err statement don't
trigger for the cases that just break.

Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
Link: https://github.com/ClangBuiltLinux/linux/issues/502
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 drivers/scsi/ibmvscsi/ibmvscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 727c31dc11a0..6714d8043e62 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2118,7 +2118,7 @@ static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
 static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 {
 	unsigned long flags;
-	int rc;
+	int rc = 0;
 	char *action = "reset";
 
 	spin_lock_irqsave(hostdata->host->host_lock, flags);
-- 
2.22.0.rc2

[PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Nathan Chancellor]

clang warns:

drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
        case IBMVSCSI_HOST_ACTION_NONE:
             ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
here
        if (rc) {
            ^~

Initialize rc to zero so that the atomic_set and dev_err statement don't
trigger for the cases that just break.

Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
Link: https://github.com/ClangBuiltLinux/linux/issues/502
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 drivers/scsi/ibmvscsi/ibmvscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 727c31dc11a0..6714d8043e62 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2118,7 +2118,7 @@ static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
 static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 {
 	unsigned long flags;
-	int rc;
+	int rc = 0;
 	char *action = "reset";
 
 	spin_lock_irqsave(hostdata->host->host_lock, flags);
-- 
2.22.0.rc2

Re: [PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Michael Ellerman]

Hi Nathan,

Nathan Chancellor <natechancellor@gmail.com> writes:
> clang warns:
>
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>         case IBMVSCSI_HOST_ACTION_NONE:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
> here
>         if (rc) {
>             ^~
>
> Initialize rc to zero so that the atomic_set and dev_err statement don't
> trigger for the cases that just break.
>
> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
> Link: https://github.com/ClangBuiltLinux/linux/issues/502
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  drivers/scsi/ibmvscsi/ibmvscsi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..6714d8043e62 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2118,7 +2118,7 @@ static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
>  static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>  {
>  	unsigned long flags;
> -	int rc;
> +	int rc = 0;
>  	char *action = "reset";
>  
>  	spin_lock_irqsave(hostdata->host->host_lock, flags);

It's always preferable IMHO to keep any initialisation as localised as
possible, so that the compiler can continue to warn about uninitialised
usages elsewhere. In this case that would mean doing the rc = 0 in the
switch, something like:

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 727c31dc11a0..7ee5755cf636 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2123,9 +2123,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 
        spin_lock_irqsave(hostdata->host->host_lock, flags);
        switch (hostdata->action) {
-       case IBMVSCSI_HOST_ACTION_NONE:
-       case IBMVSCSI_HOST_ACTION_UNBLOCK:
-               break;
        case IBMVSCSI_HOST_ACTION_RESET:
                spin_unlock_irqrestore(hostdata->host->host_lock, flags);
                rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
@@ -2142,7 +2139,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
                if (!rc)
                        rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
                break;
+       case IBMVSCSI_HOST_ACTION_NONE:
+       case IBMVSCSI_HOST_ACTION_UNBLOCK:
        default:
+               rc = 0;
                break;
        }


But then that makes me wonder if that's actually correct?

If we get an action that we don't recognise should we just throw it away
like that? (by doing hostdata->action = IBMVSCSI_HOST_ACTION_NONE). Tyrel?

cheers

Re: [PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Michael Ellerman]

Hi Nathan,

Nathan Chancellor <natechancellor@gmail.com> writes:
> clang warns:
>
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>         case IBMVSCSI_HOST_ACTION_NONE:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
> here
>         if (rc) {
>             ^~
>
> Initialize rc to zero so that the atomic_set and dev_err statement don't
> trigger for the cases that just break.
>
> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
> Link: https://github.com/ClangBuiltLinux/linux/issues/502
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  drivers/scsi/ibmvscsi/ibmvscsi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..6714d8043e62 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2118,7 +2118,7 @@ static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
>  static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>  {
>  	unsigned long flags;
> -	int rc;
> +	int rc = 0;
>  	char *action = "reset";
>  
>  	spin_lock_irqsave(hostdata->host->host_lock, flags);

It's always preferable IMHO to keep any initialisation as localised as
possible, so that the compiler can continue to warn about uninitialised
usages elsewhere. In this case that would mean doing the rc = 0 in the
switch, something like:

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 727c31dc11a0..7ee5755cf636 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2123,9 +2123,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 
        spin_lock_irqsave(hostdata->host->host_lock, flags);
        switch (hostdata->action) {
-       case IBMVSCSI_HOST_ACTION_NONE:
-       case IBMVSCSI_HOST_ACTION_UNBLOCK:
-               break;
        case IBMVSCSI_HOST_ACTION_RESET:
                spin_unlock_irqrestore(hostdata->host->host_lock, flags);
                rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
@@ -2142,7 +2139,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
                if (!rc)
                        rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
                break;
+       case IBMVSCSI_HOST_ACTION_NONE:
+       case IBMVSCSI_HOST_ACTION_UNBLOCK:
        default:
+               rc = 0;
                break;
        }


But then that makes me wonder if that's actually correct?

If we get an action that we don't recognise should we just throw it away
like that? (by doing hostdata->action = IBMVSCSI_HOST_ACTION_NONE). Tyrel?

cheers

Re: [PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Nathan Chancellor]

Hi Michael,

On Sun, Jun 02, 2019 at 08:15:38PM +1000, Michael Ellerman wrote:
> Hi Nathan,
> 
> It's always preferable IMHO to keep any initialisation as localised as
> possible, so that the compiler can continue to warn about uninitialised
> usages elsewhere. In this case that would mean doing the rc = 0 in the
> switch, something like:

I am certainly okay with implementing this in a v2. I mulled over which
would be preferred, I suppose I guessed wrong :) Thank you for the
review and input.

> 
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..7ee5755cf636 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2123,9 +2123,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>  
>         spin_lock_irqsave(hostdata->host->host_lock, flags);
>         switch (hostdata->action) {
> -       case IBMVSCSI_HOST_ACTION_NONE:
> -       case IBMVSCSI_HOST_ACTION_UNBLOCK:
> -               break;
>         case IBMVSCSI_HOST_ACTION_RESET:
>                 spin_unlock_irqrestore(hostdata->host->host_lock, flags);
>                 rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
> @@ -2142,7 +2139,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>                 if (!rc)
>                         rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
>                 break;
> +       case IBMVSCSI_HOST_ACTION_NONE:
> +       case IBMVSCSI_HOST_ACTION_UNBLOCK:
>         default:
> +               rc = 0;
>                 break;
>         }
> 
> 
> But then that makes me wonder if that's actually correct?
> 
> If we get an action that we don't recognise should we just throw it away
> like that? (by doing hostdata->action = IBMVSCSI_HOST_ACTION_NONE). Tyrel?

However, because of this, I will hold off on v2 until Tyrel can give
some feedback.

Thanks,
Nathan

Re: [PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Nathan Chancellor]

Hi Michael,

On Sun, Jun 02, 2019 at 08:15:38PM +1000, Michael Ellerman wrote:
> Hi Nathan,
> 
> It's always preferable IMHO to keep any initialisation as localised as
> possible, so that the compiler can continue to warn about uninitialised
> usages elsewhere. In this case that would mean doing the rc = 0 in the
> switch, something like:

I am certainly okay with implementing this in a v2. I mulled over which
would be preferred, I suppose I guessed wrong :) Thank you for the
review and input.

> 
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..7ee5755cf636 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2123,9 +2123,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>  
>         spin_lock_irqsave(hostdata->host->host_lock, flags);
>         switch (hostdata->action) {
> -       case IBMVSCSI_HOST_ACTION_NONE:
> -       case IBMVSCSI_HOST_ACTION_UNBLOCK:
> -               break;
>         case IBMVSCSI_HOST_ACTION_RESET:
>                 spin_unlock_irqrestore(hostdata->host->host_lock, flags);
>                 rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
> @@ -2142,7 +2139,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>                 if (!rc)
>                         rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
>                 break;
> +       case IBMVSCSI_HOST_ACTION_NONE:
> +       case IBMVSCSI_HOST_ACTION_UNBLOCK:
>         default:
> +               rc = 0;
>                 break;
>         }
> 
> 
> But then that makes me wonder if that's actually correct?
> 
> If we get an action that we don't recognise should we just throw it away
> like that? (by doing hostdata->action = IBMVSCSI_HOST_ACTION_NONE). Tyrel?

However, because of this, I will hold off on v2 until Tyrel can give
some feedback.

Thanks,
Nathan

Re: [PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Christophe Leroy]

Le 31/05/2019 à 20:53, Nathan Chancellor a écrit :
> clang warns:
> 
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>          case IBMVSCSI_HOST_ACTION_NONE:
>               ^~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
> here
>          if (rc) {
>              ^~
> 
> Initialize rc to zero so that the atomic_set and dev_err statement don't
> trigger for the cases that just break.
> 
> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
> Link: https://github.com/ClangBuiltLinux/linux/issues/502
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>   drivers/scsi/ibmvscsi/ibmvscsi.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..6714d8043e62 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2118,7 +2118,7 @@ static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
>   static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>   {
>   	unsigned long flags;
> -	int rc;
> +	int rc = 0;

I don't think the above is the best solution, as it hides the warning 
instead of really fixing it.

Your problem is that some legs of the switch are missing setting the 
value of rc, it would therefore be better to fix the legs instead of 
setting a default value which may not be correct for every case, 
allthough it may be at the time being.

Christophe


>   	char *action = "reset";
>   
>   	spin_lock_irqsave(hostdata->host->host_lock, flags);
> 

[PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Nathan Chancellor]

clang warns:

drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
        case IBMVSCSI_HOST_ACTION_NONE:
             ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
here
        if (rc) {
            ^~

Initialize rc to zero in the case statements that clang mentions so that
the atomic_set and dev_err statement don't trigger for them.

Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
Link: https://github.com/ClangBuiltLinux/linux/issues/502
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

v1 -> v2:

* Initialize rc in the case statements, rather than at the top of the
  function, as suggested by Michael.

 drivers/scsi/ibmvscsi/ibmvscsi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 65053daef5f7..3b5647d622d9 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2109,9 +2109,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 
 	spin_lock_irqsave(hostdata->host->host_lock, flags);
 	switch (hostdata->action) {
-	case IBMVSCSI_HOST_ACTION_NONE:
-	case IBMVSCSI_HOST_ACTION_UNBLOCK:
-		break;
 	case IBMVSCSI_HOST_ACTION_RESET:
 		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 		rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
@@ -2128,7 +2125,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 		if (!rc)
 			rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
 		break;
+	case IBMVSCSI_HOST_ACTION_NONE:
+	case IBMVSCSI_HOST_ACTION_UNBLOCK:
 	default:
+		rc = 0;
 		break;
 	}
 
-- 
2.22.0.rc3

[PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Nathan Chancellor]

clang warns:

drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
        case IBMVSCSI_HOST_ACTION_NONE:
             ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
here
        if (rc) {
            ^~

Initialize rc to zero in the case statements that clang mentions so that
the atomic_set and dev_err statement don't trigger for them.

Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
Link: https://github.com/ClangBuiltLinux/linux/issues/502
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

v1 -> v2:

* Initialize rc in the case statements, rather than at the top of the
  function, as suggested by Michael.

 drivers/scsi/ibmvscsi/ibmvscsi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 65053daef5f7..3b5647d622d9 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2109,9 +2109,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 
 	spin_lock_irqsave(hostdata->host->host_lock, flags);
 	switch (hostdata->action) {
-	case IBMVSCSI_HOST_ACTION_NONE:
-	case IBMVSCSI_HOST_ACTION_UNBLOCK:
-		break;
 	case IBMVSCSI_HOST_ACTION_RESET:
 		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 		rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
@@ -2128,7 +2125,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 		if (!rc)
 			rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
 		break;
+	case IBMVSCSI_HOST_ACTION_NONE:
+	case IBMVSCSI_HOST_ACTION_UNBLOCK:
 	default:
+		rc = 0;
 		break;
 	}
 
-- 
2.22.0.rc3

Re: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/03/2019 03:19 PM, Nathan Chancellor wrote:
> clang warns:
> 
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>         case IBMVSCSI_HOST_ACTION_NONE:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
> here
>         if (rc) {
>             ^~
> 
> Initialize rc to zero in the case statements that clang mentions so that
> the atomic_set and dev_err statement don't trigger for them.
> 
> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
> Link: https://github.com/ClangBuiltLinux/linux/issues/502
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>

Re: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/03/2019 03:19 PM, Nathan Chancellor wrote:
> clang warns:
> 
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>         case IBMVSCSI_HOST_ACTION_NONE:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
> here
>         if (rc) {
>             ^~
> 
> Initialize rc to zero in the case statements that clang mentions so that
> the atomic_set and dev_err statement don't trigger for them.
> 
> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
> Link: https://github.com/ClangBuiltLinux/linux/issues/502
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>

Re: [PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/02/2019 03:15 AM, Michael Ellerman wrote:
> Hi Nathan,
> 
> Nathan Chancellor <natechancellor@gmail.com> writes:
>> clang warns:
>>
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>         case IBMVSCSI_HOST_ACTION_NONE:
>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
>> here
>>         if (rc) {
>>             ^~
>>
>> Initialize rc to zero so that the atomic_set and dev_err statement don't
>> trigger for the cases that just break.
>>
>> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
>> Link: https://github.com/ClangBuiltLinux/linux/issues/502
>> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
>> ---
>>  drivers/scsi/ibmvscsi/ibmvscsi.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
>> index 727c31dc11a0..6714d8043e62 100644
>> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
>> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
>> @@ -2118,7 +2118,7 @@ static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
>>  static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>>  {
>>  	unsigned long flags;
>> -	int rc;
>> +	int rc = 0;
>>  	char *action = "reset";
>>  
>>  	spin_lock_irqsave(hostdata->host->host_lock, flags);
> 
> It's always preferable IMHO to keep any initialisation as localised as
> possible, so that the compiler can continue to warn about uninitialised
> usages elsewhere. In this case that would mean doing the rc = 0 in the
> switch, something like:
> 
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..7ee5755cf636 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2123,9 +2123,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>  
>         spin_lock_irqsave(hostdata->host->host_lock, flags);
>         switch (hostdata->action) {
> -       case IBMVSCSI_HOST_ACTION_NONE:
> -       case IBMVSCSI_HOST_ACTION_UNBLOCK:
> -               break;
>         case IBMVSCSI_HOST_ACTION_RESET:
>                 spin_unlock_irqrestore(hostdata->host->host_lock, flags);
>                 rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
> @@ -2142,7 +2139,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>                 if (!rc)
>                         rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
>                 break;
> +       case IBMVSCSI_HOST_ACTION_NONE:
> +       case IBMVSCSI_HOST_ACTION_UNBLOCK:
>         default:
> +               rc = 0;
>                 break;
>         }
> 
> 
> But then that makes me wonder if that's actually correct?
> 
> If we get an action that we don't recognise should we just throw it away
> like that? (by doing hostdata->action = IBMVSCSI_HOST_ACTION_NONE). Tyrel?

On initial pass I was ok with this, but after thinking on it I think it is more
subtle.

The right approach is to set rc = 0 for HOST_ACTION_UNBLOCK as we want to fall
through. For HOST_ACTION_NONE and default we need to return directly from the
function.

-Tyrel

> 
> cheers
> 

Re: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/03/2019 04:25 PM, Tyrel Datwyler wrote:
> On 06/03/2019 03:19 PM, Nathan Chancellor wrote:
>> clang warns:
>>
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>         case IBMVSCSI_HOST_ACTION_NONE:
>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
>> here
>>         if (rc) {
>>             ^~
>>
>> Initialize rc to zero in the case statements that clang mentions so that
>> the atomic_set and dev_err statement don't trigger for them.
>>
>> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
>> Link: https://github.com/ClangBuiltLinux/linux/issues/502
>> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
>> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> 
> Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>
> 

On second thought NACK. See my response to Michael earlier in the thread.

I think this is the better solution:

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 727c31dc11a0..c3cf05dd8733 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2123,8 +2123,8 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
*hostdata)

        spin_lock_irqsave(hostdata->host->host_lock, flags);
        switch (hostdata->action) {
-       case IBMVSCSI_HOST_ACTION_NONE:
        case IBMVSCSI_HOST_ACTION_UNBLOCK:
+               rc = 0;
                break;
        case IBMVSCSI_HOST_ACTION_RESET:
                spin_unlock_irqrestore(hostdata->host->host_lock, flags);
@@ -2142,8 +2142,9 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
*hostdata)
                if (!rc)
                        rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
                break;
+       case IBMVSCSI_HOST_ACTION_NONE:
        default:
-               break;
+               return;
        }

        hostdata->action = IBMVSCSI_HOST_ACTION_NONE;

Re: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/03/2019 04:25 PM, Tyrel Datwyler wrote:
> On 06/03/2019 03:19 PM, Nathan Chancellor wrote:
>> clang warns:
>>
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>         case IBMVSCSI_HOST_ACTION_NONE:
>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
>> here
>>         if (rc) {
>>             ^~
>>
>> Initialize rc to zero in the case statements that clang mentions so that
>> the atomic_set and dev_err statement don't trigger for them.
>>
>> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
>> Link: https://github.com/ClangBuiltLinux/linux/issues/502
>> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
>> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> 
> Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>
> 

On second thought NACK. See my response to Michael earlier in the thread.

I think this is the better solution:

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 727c31dc11a0..c3cf05dd8733 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2123,8 +2123,8 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
*hostdata)

        spin_lock_irqsave(hostdata->host->host_lock, flags);
        switch (hostdata->action) {
-       case IBMVSCSI_HOST_ACTION_NONE:
        case IBMVSCSI_HOST_ACTION_UNBLOCK:
+               rc = 0;
                break;
        case IBMVSCSI_HOST_ACTION_RESET:
                spin_unlock_irqrestore(hostdata->host->host_lock, flags);
@@ -2142,8 +2142,9 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
*hostdata)
                if (!rc)
                        rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
                break;
+       case IBMVSCSI_HOST_ACTION_NONE:
        default:
-               break;
+               return;
        }

        hostdata->action = IBMVSCSI_HOST_ACTION_NONE;

Re: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/03/2019 04:34 PM, Tyrel Datwyler wrote:
> On 06/03/2019 04:25 PM, Tyrel Datwyler wrote:
>> On 06/03/2019 03:19 PM, Nathan Chancellor wrote:
>>> clang warns:
>>>
>>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>>         case IBMVSCSI_HOST_ACTION_NONE:
>>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>>> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
>>> here
>>>         if (rc) {
>>>             ^~
>>>
>>> Initialize rc to zero in the case statements that clang mentions so that
>>> the atomic_set and dev_err statement don't trigger for them.
>>>
>>> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
>>> Link: https://github.com/ClangBuiltLinux/linux/issues/502
>>> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
>>> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
>>
>> Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>
>>
> 
> On second thought NACK. See my response to Michael earlier in the thread.
> 
> I think this is the better solution:
> 
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..c3cf05dd8733 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2123,8 +2123,8 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
> *hostdata)
> 
>         spin_lock_irqsave(hostdata->host->host_lock, flags);
>         switch (hostdata->action) {
> -       case IBMVSCSI_HOST_ACTION_NONE:
>         case IBMVSCSI_HOST_ACTION_UNBLOCK:
> +               rc = 0;
>                 break;
>         case IBMVSCSI_HOST_ACTION_RESET:
>                 spin_unlock_irqrestore(hostdata->host->host_lock, flags);
> @@ -2142,8 +2142,9 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
> *hostdata)
>                 if (!rc)
>                         rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
>                 break;
> +       case IBMVSCSI_HOST_ACTION_NONE:
>         default:
> -               break;

Need a spin_unlock_irqrestore() here before the return.

-Tyrel

> +               return;
>         }
> 
>         hostdata->action = IBMVSCSI_HOST_ACTION_NONE;
> 

Re: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/03/2019 04:34 PM, Tyrel Datwyler wrote:
> On 06/03/2019 04:25 PM, Tyrel Datwyler wrote:
>> On 06/03/2019 03:19 PM, Nathan Chancellor wrote:
>>> clang warns:
>>>
>>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>>         case IBMVSCSI_HOST_ACTION_NONE:
>>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>>> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
>>> here
>>>         if (rc) {
>>>             ^~
>>>
>>> Initialize rc to zero in the case statements that clang mentions so that
>>> the atomic_set and dev_err statement don't trigger for them.
>>>
>>> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
>>> Link: https://github.com/ClangBuiltLinux/linux/issues/502
>>> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
>>> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
>>
>> Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>
>>
> 
> On second thought NACK. See my response to Michael earlier in the thread.
> 
> I think this is the better solution:
> 
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..c3cf05dd8733 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2123,8 +2123,8 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
> *hostdata)
> 
>         spin_lock_irqsave(hostdata->host->host_lock, flags);
>         switch (hostdata->action) {
> -       case IBMVSCSI_HOST_ACTION_NONE:
>         case IBMVSCSI_HOST_ACTION_UNBLOCK:
> +               rc = 0;
>                 break;
>         case IBMVSCSI_HOST_ACTION_RESET:
>                 spin_unlock_irqrestore(hostdata->host->host_lock, flags);
> @@ -2142,8 +2142,9 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data
> *hostdata)
>                 if (!rc)
>                         rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
>                 break;
> +       case IBMVSCSI_HOST_ACTION_NONE:
>         default:
> -               break;

Need a spin_unlock_irqrestore() here before the return.

-Tyrel

> +               return;
>         }
> 
>         hostdata->action = IBMVSCSI_HOST_ACTION_NONE;
> 

[PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Nathan Chancellor]

clang warns:

drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
        case IBMVSCSI_HOST_ACTION_NONE:
             ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
here
        if (rc) {
            ^~

Initialize rc in the IBMVSCSI_HOST_ACTION_UNBLOCK case statement then
shuffle IBMVSCSI_HOST_ACTION_NONE down to the default case statement and
make it return early so that rc is never used uninitialized in this
function.

Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
Link: https://github.com/ClangBuiltLinux/linux/issues/502
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Suggested-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

v1 -> v2:

* Initialize rc in the case statements, rather than at the top of the
  function, as suggested by Michael.
  
v2 -> v3:

* default and IBMVSCSI_HOST_ACTION_NONE now return early from the
  function, as requested by Tyrel.

 drivers/scsi/ibmvscsi/ibmvscsi.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 65053daef5f7..7f66a7783209 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2109,8 +2109,8 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 
 	spin_lock_irqsave(hostdata->host->host_lock, flags);
 	switch (hostdata->action) {
-	case IBMVSCSI_HOST_ACTION_NONE:
 	case IBMVSCSI_HOST_ACTION_UNBLOCK:
+		rc = 0;
 		break;
 	case IBMVSCSI_HOST_ACTION_RESET:
 		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
@@ -2128,8 +2128,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 		if (!rc)
 			rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
 		break;
+	case IBMVSCSI_HOST_ACTION_NONE:
 	default:
-		break;
+		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+		return;
 	}
 
 	hostdata->action = IBMVSCSI_HOST_ACTION_NONE;
-- 
2.22.0.rc3

[PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Nathan Chancellor]

clang warns:

drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
        case IBMVSCSI_HOST_ACTION_NONE:
             ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
here
        if (rc) {
            ^~

Initialize rc in the IBMVSCSI_HOST_ACTION_UNBLOCK case statement then
shuffle IBMVSCSI_HOST_ACTION_NONE down to the default case statement and
make it return early so that rc is never used uninitialized in this
function.

Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
Link: https://github.com/ClangBuiltLinux/linux/issues/502
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Suggested-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

v1 -> v2:

* Initialize rc in the case statements, rather than at the top of the
  function, as suggested by Michael.
  
v2 -> v3:

* default and IBMVSCSI_HOST_ACTION_NONE now return early from the
  function, as requested by Tyrel.

 drivers/scsi/ibmvscsi/ibmvscsi.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 65053daef5f7..7f66a7783209 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2109,8 +2109,8 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 
 	spin_lock_irqsave(hostdata->host->host_lock, flags);
 	switch (hostdata->action) {
-	case IBMVSCSI_HOST_ACTION_NONE:
 	case IBMVSCSI_HOST_ACTION_UNBLOCK:
+		rc = 0;
 		break;
 	case IBMVSCSI_HOST_ACTION_RESET:
 		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
@@ -2128,8 +2128,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 		if (!rc)
 			rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
 		break;
+	case IBMVSCSI_HOST_ACTION_NONE:
 	default:
-		break;
+		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+		return;
 	}
 
 	hostdata->action = IBMVSCSI_HOST_ACTION_NONE;
-- 
2.22.0.rc3

Re: [PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/03/2019 04:44 PM, Nathan Chancellor wrote:
> clang warns:
> 
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>         case IBMVSCSI_HOST_ACTION_NONE:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
> here
>         if (rc) {
>             ^~
> 
> Initialize rc in the IBMVSCSI_HOST_ACTION_UNBLOCK case statement then
> shuffle IBMVSCSI_HOST_ACTION_NONE down to the default case statement and
> make it return early so that rc is never used uninitialized in this
> function.
> 
> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
> Link: https://github.com/ClangBuiltLinux/linux/issues/502
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Suggested-by: Tyrel Datwyler <tyreld@linux.ibm.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>

Re: [PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Tyrel Datwyler]

On 06/03/2019 04:44 PM, Nathan Chancellor wrote:
> clang warns:
> 
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>         case IBMVSCSI_HOST_ACTION_NONE:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
> here
>         if (rc) {
>             ^~
> 
> Initialize rc in the IBMVSCSI_HOST_ACTION_UNBLOCK case statement then
> shuffle IBMVSCSI_HOST_ACTION_NONE down to the default case statement and
> make it return early so that rc is never used uninitialized in this
> function.
> 
> Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
> Link: https://github.com/ClangBuiltLinux/linux/issues/502
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Suggested-by: Tyrel Datwyler <tyreld@linux.ibm.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>

Re: [PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Martin K. Petersen]

Nathan,

> clang warns:
>
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>         case IBMVSCSI_HOST_ACTION_NONE:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~

Applied to 5.3/scsi-queue, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Martin K. Petersen]

Nathan,

> clang warns:
>
> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>         case IBMVSCSI_HOST_ACTION_NONE:
>              ^~~~~~~~~~~~~~~~~~~~~~~~~

Applied to 5.3/scsi-queue, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Michael Ellerman]

"Martin K. Petersen" <martin.petersen@oracle.com> writes:
> Nathan,
>
>> clang warns:
>>
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>         case IBMVSCSI_HOST_ACTION_NONE:
>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>
> Applied to 5.3/scsi-queue, thanks!

Thanks all.

cheers

Re: [PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Michael Ellerman]

"Martin K. Petersen" <martin.petersen@oracle.com> writes:
> Nathan,
>
>> clang warns:
>>
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>         case IBMVSCSI_HOST_ACTION_NONE:
>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>
> Applied to 5.3/scsi-queue, thanks!

Thanks all.

cheers

Re: [PATCH v3] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

[Michael Ellerman]

"Martin K. Petersen" <martin.petersen@oracle.com> writes:
> Nathan,
>
>> clang warns:
>>
>> drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
>> uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
>>         case IBMVSCSI_HOST_ACTION_NONE:
>>              ^~~~~~~~~~~~~~~~~~~~~~~~~
>
> Applied to 5.3/scsi-queue, thanks!

Thanks all.

cheers