aic7xxx driver large integer warning

aic7xxx driver large integer warning

[Miguel Angel Flores]

Hi list.

As I said yesterday, the 2.6.10rc3 kernel warns compiling the aic7xxxx 
SCSI driver:

---
drivers/scsi/aic7xxx/aic7xxx_osm_pci.c: In function 
`ahc_linux_pci_dev_probe':
drivers/scsi/aic7xxx/aic7xxx_osm_pci.c:229: warning: large integer 
implicitly truncated to unsigned type
---

[aic7xxx_osm_pci.c]
    mask_39bit = 0x7FFFFFFFFFULL;

mask_39bit type is dma_addr_t. However the length of dma_addr_t is 
defined in types.h.

[types.h]
    #ifdef CONFIG_HIGHMEM64G
    typedef u64 dma_addr_t;
    #else
    typedef u32 dma_addr_t;
    #endif
    typedef u64 dma64_addr_t;

I think the correct solution is to make the assignement only if 
CONFIG_HIGHMEM64G is defined:

[aic7xxx_osm_pci.c]
        mask_39bit = 0x7FFFFFFFFFULL;  //assignement
        if (sizeof(dma_addr_t) > 4 //CONFIG_HIGHMEM64G is defined
         && ahc_linux_get_memsize() > 0x80000000
         && pci_set_dma_mask(pdev, mask_39bit) == 0) {

            /* the correct position of the assignement IMHO */

            ahc->flags |= AHC_39BIT_ADDRESSING;
            ahc->platform_data->hw_dma_mask = mask_39bit;
        } else {
            if (pci_set_dma_mask(pdev, 0xFFFFFFFF)) {
                printk(KERN_WARNING "aic7xxx: No suitable DMA 
available.\n");
                        return (-ENODEV);
            }
            ahc->platform_data->hw_dma_mask = 0xFFFFFFFF;

Before I post a new patch, I wish to know your opinion.

Thanks,
MaF

Re: aic7xxx driver large integer warning

[Alan Cox]

On Llu, 2004-12-06 at 00:23, Miguel Angel Flores wrote:
> drivers/scsi/aic7xxx/aic7xxx_osm_pci.c:229: warning: large integer 
> implicitly truncated to unsigned type
> ---

Add (dma_addr_t) casts and it will go away. The compiler just wants to
know you mean it.

Re: aic7xxx driver large integer warning

[Miguel Angel Flores]

Alan Cox wrote:

>Add (dma_addr_t) casts and it will go away. The compiler just wants to
>know you mean it.
>  
>
Sure, but the 39 bit variable is only used when the type of dma_addr_t 
is u64. I think that is more clean to put this assignement inside the if 
block, like the rest of the CONFIG_HIGHMEM64G code. Anyway the 
(dma_addr_t) cast can be added too.

¿how you would solve this?

Cheers,
MaF

Re: aic7xxx driver large integer warning

[Alan Cox]

On Llu, 2004-12-06 at 17:30, Miguel Angel Flores wrote:
> Sure, but the 39 bit variable is only used when the type of dma_addr_t 
> is u64. I think that is more clean to put this assignement inside the if 
> block, like the rest of the CONFIG_HIGHMEM64G code. Anyway the 
> (dma_addr_t) cast can be added too.
> 
> ¿how you would solve this?

I'd just add the cast. The compiler will truncate it to FFFFFFFF if
appropriate.