2006-01-17 16:35:28

by Paul Fulghum

Subject: [PATCH] synclink_gt fix size of register value storage

Fix incorrect variable size used to hold
register value. This bug might wipe out a portion of the
TCR value when setting the interface options.

Signed-off-by: Paul Fulghum <[email protected]>


--- linux-2.6.16-rc1/drivers/char/synclink_gt.c 2006-01-17 09:31:20.000000000 -0600
+++ linux-2.6.16-rc1-mg/drivers/char/synclink_gt.c 2006-01-17 10:22:48.000000000 -0600
@@ -2630,7 +2630,7 @@ static int get_interface(struct slgt_inf
static int set_interface(struct slgt_info *info, int if_mode)
{
unsigned long flags;
- unsigned char val;
+ unsigned short val;

DBGINFO(("%s set_interface=%x)\n", info->device_name, if_mode));
spin_lock_irqsave(&info->lock,flags);

2006-01-18 12:03:52

by Jiri Slaby

Subject: Re: [PATCH] synclink_gt fix size of register value storage

Paul Fulghum wrote:
> Fix incorrect variable size used to hold
> register value. This bug might wipe out a portion of the
> TCR value when setting the interface options.
>
> Signed-off-by: Paul Fulghum <[email protected]>
>
>
> --- linux-2.6.16-rc1/drivers/char/synclink_gt.c 2006-01-17 09:31:20.000000000 -0600
> +++ linux-2.6.16-rc1-mg/drivers/char/synclink_gt.c 2006-01-17 10:22:48.000000000 -0600
> @@ -2630,7 +2630,7 @@ static int get_interface(struct slgt_inf
> static int set_interface(struct slgt_info *info, int if_mode)
> {
> unsigned long flags;
> - unsigned char val;
> + unsigned short val;
Shouldn't be this u16 rather than ushort?

regards,
--
Jiri Slaby http://www.fi.muni.cz/~xslaby
\_.-^-._ [email protected] _.-^-._/
B67499670407CE62ACC8 22A032CC55C339D47A7E

2006-01-18 15:28:41

by Paul Fulghum

Subject: Re: [PATCH] synclink_gt fix size of register value storage

Jiri Slaby wrote:
>>- unsigned char val;
>>+ unsigned short val;
>
> Shouldn't be this u16 rather than ushort?

It could be argued that way.
A quick search of CodingStyle does not
reference the uXX types.

unsigned short is guaranteed to be
at least 16 bits, so no data is lost.
The value is written to the register using
writew(), so no more than 16 bits are used.
Using unsigned short here will always work.

Do you know of a Linux environment where
unsigned short is not 16 bits?

--
Paul Fulghum
Microgate Systems, Ltd.