Re: [PATCH] [SCSI] aacraid: silence two GCC warnings

From: James Bottomley
Date: Wed Feb 20 2013 - 05:40:33 EST


On Sat, 2013-02-09 at 21:09 +0100, Paul Bolle wrote:
> Compiling src.o for a 32 bit system triggers two GCC warnings:
> drivers/scsi/aacraid/src.c: In function âaac_src_deliver_messageâ:
> drivers/scsi/aacraid/src.c:410:3: warning: right shift count >= width of type [enabled by default]
> drivers/scsi/aacraid/src.c:434:2: warning: right shift count >= width of type [enabled by default]
>
> Silence these warnings by casting the 'address' variable (of type
> dma_addr_t) to u64 on those two lines.
>
> Signed-off-by: Paul Bolle <pebolle@xxxxxxxxxx>
> ---
> 0) Compile tested only.
>
> 1) Changing '0L' to 'OUL' might be a bit of cargo cult programming. I
> doubt it's necessary. Members of that cult might also change
> '0xffffffff' to '0xffffffffUL', but I didn't.
>
> drivers/scsi/aacraid/src.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/aacraid/src.c b/drivers/scsi/aacraid/src.c
> index 3b021ec..dfa8a37 100644
> --- a/drivers/scsi/aacraid/src.c
> +++ b/drivers/scsi/aacraid/src.c
> @@ -407,7 +407,7 @@ static int aac_src_deliver_message(struct fib *fib)
> fib->hw_fib_va->header.StructType = FIB_MAGIC2;
> fib->hw_fib_va->header.SenderFibAddress = (u32)address;
> fib->hw_fib_va->header.u.TimeStamp = 0;
> - BUG_ON((u32)(address >> 32) != 0L);
> + BUG_ON(((u64)address >> 32) != 0UL);

Actually, this isn't the right way to do this. The correct way would be
address >> 16 >> 16, but no-one is expected to remember this, so we have
it macroised in kernel.h as upper_32_bits().

So this should become

BUG_ON(upper_32_bits(address) != 0L);

and a similar change for the below.

James

> address |= fibsize;
> } else {
> /* Calculate the amount to the fibsize bits */
> @@ -431,7 +431,7 @@ static int aac_src_deliver_message(struct fib *fib)
> address |= fibsize;
> }
>
> - src_writel(dev, MUnit.IQ_H, (address >> 32) & 0xffffffff);
> + src_writel(dev, MUnit.IQ_H, ((u64)address >> 32) & 0xffffffff);
> src_writel(dev, MUnit.IQ_L, address & 0xffffffff);
>
> return 0;


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