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

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

[Paul Bolle]

Compiling src.o for a 32 bit system triggers two GCC warnings:
    drivers/scsi/aacraid/src.c: In function ‘aac_src_deliver_message’:
    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@tiscali.nl>
---
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);
 		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;
-- 
1.8.1.2

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

[James Bottomley]

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 ‘aac_src_deliver_message’:
>     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@tiscali.nl>
> ---
> 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;

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

[Paul Bolle]

On Wed, 2013-02-20 at 10:40 +0000, James Bottomley wrote:
> On Sat, 2013-02-09 at 21:09 +0100, Paul Bolle wrote:
> > --- 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);

Thanks. I hadn't yet stumbled onto that macro.

> and a similar change for the below.

I hope to send an updated patch shortly.


Paul Bolle

[PATCH v2] [SCSI] aacraid: suppress two GCC warnings

[Paul Bolle]

Building src.o for a 32 bit system triggers two GCC warnings:
    drivers/scsi/aacraid/src.c: In function ‘aac_src_deliver_message’:
    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]

These warnings are caused by a right shift of 32. Use upper_32_bits() to
suppress them.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
---
0) Instead of a cast to u64, this version uses upper_32_bits() as James
suggested. I also stopped changing 0L to 0UL, because I keep having
doubts about the cargo cult.

1) Still compile tested only, but now on v3.8.

 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..e2e3492 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(upper_32_bits(address) != 0L);
 		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, upper_32_bits(address) & 0xffffffff);
 	src_writel(dev, MUnit.IQ_L, address & 0xffffffff);
 
 	return 0;
-- 
1.8.1.2