ate_resource->lowest_free_index signed or unsigned?

ate_resource->lowest_free_index signed or unsigned?

[Roel Kluin]

In arch/ia64/include/asm/sn/pcibr_provider.h:94

struct ate_resource{
        u64 *ate;
        u64 num_ate;
        u64 lowest_free_index;
};

as you see lowest_free_index is unsigned,

but in alloc_ate_resource() and free_ate_resource() it is
treated as signed:

static inline void free_ate_resource(struct ate_resource *ate_resource,
                                     int start)
{
        mark_ate(ate_resource, start, ate_resource->ate[start], 0);
        if ((ate_resource->lowest_free_index > start) ||
            (ate_resource->lowest_free_index < 0))
                ate_resource->lowest_free_index = start;
}

/*
 * alloc_ate_resource:  Allocate the requested number of ATEs.
 */
static inline int alloc_ate_resource(struct ate_resource *ate_resource,
                                     int ate_needed)
{
        int start_index;

        /*
         * Check for ate exhaustion.
         */
        if (ate_resource->lowest_free_index < 0)
                return -1;

        /*
         * Find the required number of free consecutive ates.
         */
        start_index             find_free_ate(ate_resource, ate_resource->lowest_free_index,
                          ate_needed);
        if (start_index >= 0)
                mark_ate(ate_resource, start_index, ate_needed, ate_needed);

        ate_resource->lowest_free_index             find_free_ate(ate_resource, ate_resource->lowest_free_index, 1);

        return start_index;
}

should it be signed instead?

Re: ate_resource->lowest_free_index signed or unsigned?

[Jes Sorensen]

Roel Kluin wrote:
> In arch/ia64/include/asm/sn/pcibr_provider.h:94
> 
> struct ate_resource{
>         u64 *ate;
>         u64 num_ate;
>         u64 lowest_free_index;
> };
> 
> as you see lowest_free_index is unsigned,
> 
> but in alloc_ate_resource() and free_ate_resource() it is
> treated as signed:

Hi Roel,

I don't thing it's a big issue to be honest, it just means the tests for
lowest_free_index < 0 are no-ops. I would be fine with a patch that
changes it to signed.

Cheers,
Jes


> static inline void free_ate_resource(struct ate_resource *ate_resource,
>                                      int start)
> {
>         mark_ate(ate_resource, start, ate_resource->ate[start], 0);
>         if ((ate_resource->lowest_free_index > start) ||
>             (ate_resource->lowest_free_index < 0))
>                 ate_resource->lowest_free_index = start;
> }
> 
> /*
>  * alloc_ate_resource:  Allocate the requested number of ATEs.
>  */
> static inline int alloc_ate_resource(struct ate_resource *ate_resource,
>                                      int ate_needed)
> {
>         int start_index;
> 
>         /*
>          * Check for ate exhaustion.
>          */
>         if (ate_resource->lowest_free_index < 0)
>                 return -1;
> 
>         /*
>          * Find the required number of free consecutive ates.
>          */
>         start_index >             find_free_ate(ate_resource, ate_resource->lowest_free_index,
>                           ate_needed);
>         if (start_index >= 0)
>                 mark_ate(ate_resource, start_index, ate_needed, ate_needed);
> 
>         ate_resource->lowest_free_index >             find_free_ate(ate_resource, ate_resource->lowest_free_index, 1);
> 
>         return start_index;
> }
> 
> should it be signed instead?

Re: ate_resource->lowest_free_index signed or unsigned?

[Roel Kluin]

Jes Sorensen wrote:
> Roel Kluin wrote:
>> lowest_free_index is unsigned, but in alloc_ate_resource() and
>> free_ate_resource() it is treated as signed
> 
> I don't thing it's a big issue to be honest, it just means the tests for
> lowest_free_index < 0 are no-ops. I would be fine with a patch that
> changes it to signed.

Ok, How's this? If my changelog is not clear feel free to amend it.
------------------------------>8-------------8<---------------------------------
unsigned lowest_free_index was set in alloc_ate_resource() with the return
value of find_free_ate(), which is -1 when no free ate is found. Since
unsigned, a lowest_free_index of -1, `ate exhaustion', would then not be noticed
in a subsequent call to alloc_ate_resource().

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/arch/ia64/include/asm/sn/pcibr_provider.h b/arch/ia64/include/asm/sn/pcibr_provider.h
index da205b7..b3133ef 100644
--- a/arch/ia64/include/asm/sn/pcibr_provider.h
+++ b/arch/ia64/include/asm/sn/pcibr_provider.h
@@ -94,7 +94,7 @@
 struct ate_resource{
 	u64 *ate;
 	u64 num_ate;
-	u64 lowest_free_index;
+	int lowest_free_index;
 };
 
 struct pcibus_info {

Re: ate_resource->lowest_free_index signed or unsigned?

[Jes Sorensen]

Roel Kluin wrote:
> Jes Sorensen wrote:
>> Roel Kluin wrote:
>>> lowest_free_index is unsigned, but in alloc_ate_resource() and
>>> free_ate_resource() it is treated as signed
>> I don't thing it's a big issue to be honest, it just means the tests for
>> lowest_free_index < 0 are no-ops. I would be fine with a patch that
>> changes it to signed.
> 
> Ok, How's this? If my changelog is not clear feel free to amend it.

Hi Roel,

Please make it 'long' or 's64' to keep the size in the struct.

Cheers,
Jes


> ------------------------------>8-------------8<---------------------------------
> unsigned lowest_free_index was set in alloc_ate_resource() with the return
> value of find_free_ate(), which is -1 when no free ate is found. Since
> unsigned, a lowest_free_index of -1, `ate exhaustion', would then not be noticed
> in a subsequent call to alloc_ate_resource().
> 
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
> diff --git a/arch/ia64/include/asm/sn/pcibr_provider.h b/arch/ia64/include/asm/sn/pcibr_provider.h
> index da205b7..b3133ef 100644
> --- a/arch/ia64/include/asm/sn/pcibr_provider.h
> +++ b/arch/ia64/include/asm/sn/pcibr_provider.h
> @@ -94,7 +94,7 @@
>  struct ate_resource{
>  	u64 *ate;
>  	u64 num_ate;
> -	u64 lowest_free_index;
> +	int lowest_free_index;
>  };
>  
>  struct pcibus_info {

Re: ate_resource->lowest_free_index signed or unsigned?

[Roel Kluin]

Jes Sorensen wrote:
> Roel Kluin wrote:
>> Jes Sorensen wrote:
>>> Roel Kluin wrote:
>>>> lowest_free_index is unsigned, but in alloc_ate_resource() and
>>>> free_ate_resource() it is treated as signed
>>> I don't thing it's a big issue to be honest, it just means the tests for
>>> lowest_free_index < 0 are no-ops. I would be fine with a patch that
>>> changes it to signed.

> Please make it 'long' or 's64' to keep the size in the struct.

------------------------------>8-------------8<---------------------------------
unsigned lowest_free_index was set in alloc_ate_resource() with the return
value of find_free_ate(), which is -1 when no free ate is found. Since
unsigned, a lowest_free_index of -1, `ate exhaustion', would then not be noticed
in a subsequent call to alloc_ate_resource().

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/arch/ia64/include/asm/sn/pcibr_provider.h b/arch/ia64/include/asm/sn/pcibr_provider.h
index da205b7..636d914 100644
--- a/arch/ia64/include/asm/sn/pcibr_provider.h
+++ b/arch/ia64/include/asm/sn/pcibr_provider.h
@@ -94,7 +94,7 @@
 struct ate_resource{
 	u64 *ate;
 	u64 num_ate;
-	u64 lowest_free_index;
+	s64 lowest_free_index;
 };
 
 struct pcibus_info {

Re: ate_resource->lowest_free_index signed or unsigned?

[Jes Sorensen]

Roel Kluin wrote:
> Jes Sorensen wrote:
>> Roel Kluin wrote:
>>> Jes Sorensen wrote:
>>>> Roel Kluin wrote:
>>>>> lowest_free_index is unsigned, but in alloc_ate_resource() and
>>>>> free_ate_resource() it is treated as signed
>>>> I don't thing it's a big issue to be honest, it just means the tests for
>>>> lowest_free_index < 0 are no-ops. I would be fine with a patch that
>>>> changes it to signed.
> 
>> Please make it 'long' or 's64' to keep the size in the struct.

Hi Roel,

I ran some basic tests, seems fine.

Acked-by: Jes Sorensen <jes@sgi.com>

Cheers,
Jes

> ------------------------------>8-------------8<---------------------------------
> unsigned lowest_free_index was set in alloc_ate_resource() with the return
> value of find_free_ate(), which is -1 when no free ate is found. Since
> unsigned, a lowest_free_index of -1, `ate exhaustion', would then not be noticed
> in a subsequent call to alloc_ate_resource().
> 
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
> diff --git a/arch/ia64/include/asm/sn/pcibr_provider.h b/arch/ia64/include/asm/sn/pcibr_provider.h
> index da205b7..636d914 100644
> --- a/arch/ia64/include/asm/sn/pcibr_provider.h
> +++ b/arch/ia64/include/asm/sn/pcibr_provider.h
> @@ -94,7 +94,7 @@
>  struct ate_resource{
>  	u64 *ate;
>  	u64 num_ate;
> -	u64 lowest_free_index;
> +	s64 lowest_free_index;
>  };
>  
>  struct pcibus_info {