Re: [scsi:pending 3/3] drivers/scsi/aacraid/src.c:425:2: warning: right shift count >= width of type

[Ben Collins <benmcollins13@xxxxxxxxx>]

On Jun 20, 2012, at 1:02 PM, James Bottomley wrote:

> On Wed, 2012-06-20 at 12:52 -0500, Ben Collins wrote:
>> On Jun 20, 2012, at 12:44 PM, Ben Collins wrote:
>> 
>>> On Jun 20, 2012, at 12:12 PM, wfg@xxxxxxxxxxxxxxx wrote:
>>> 
>>>> Hi Ben,
>>>> 
>>>> There are new compile warnings show up in
>>>> 
>>>> tree:   git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git pending
>>>> head:   e766db42f45c7685fce5c0d48ba74eaa97e6d715
>>>> commit: e766db42f45c7685fce5c0d48ba74eaa97e6d715 [3/3] [SCSI] aacraid: Fix endian issues in core and SRC portions of driver
>>>> 
>>>> All warnings:
>>>> 
>>>> drivers/scsi/aacraid/src.c: In function 'aac_src_deliver_message':
>>>> drivers/scsi/aacraid/src.c:425:2: warning: right shift count >= width of type [enabled by default]
>>> 
>>> Hrmm, pretty innocuous, but I guess it could be rewritten as:
>>> 
>>> #if BITS_PER_LONG > 32
>>>        src_writel(dev, MUnit.IQ_H, (address >> 32) & 0xffffffff);
>>> #else
>>>        src_writel(dev, MUnit.IQ_H, 0);
>>> #endif
>> 
>> Actually, this is wrong too, since it's a dma_addr_t, not an unsigned long, so:
>> 
>> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
>>        src_writel(dev, MUnit.IQ_H, (address >> 32) & 0xffffffff);
>> #else
>>        src_writel(dev, MUnit.IQ_H, 0);
>> #endif
> 
> Heh, three strikes and you're out.  To forestall this, the actual answer
> is
> 
> src_writel(dev, MUnit.IQ_H, upper_32_bits(address));

Saved by the misfortune of others it appears. Then I guess changing the next line to lower_32_bits() would be in order as well.

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