Re: [PATCH 1/2] cpqfc: fix for "Using too much stach" in 2.6 kernel

Dave Jones
2005-08-04T16:43:17Z

On Thu, Aug 04, 2005 at 05:56:14PM +0200, Rolf Eike Beer wrote:
> Am Donnerstag, 4. August 2005 17:40 schrieb Dave Jones:
> >On Thu, Aug 04, 2005 at 11:38:30AM +0200, Rolf Eike Beer wrote:
> > > >+ ulFibreFrame = kmalloc((2048/4), GFP_KERNEL);
> > >
> > > The size bug was already found by Dave Jones. This never should be
> > > written this way (not your fault). The array should have been
> > > [2048/sizeof(ULONG)].
> >
> >wasteful. We only ever use 2048 bytes of this array, so doubling
> >its size on 64bit is pointless, unless you make changes later on
> >in the driver. (Which I think don't make sense, as we just copy
> >32 64byte chunks).
>
> No, this is how it should have been before. This way it would have been clear
> where the magic 4 came from.

It's pointless to fix this, without fixing also CpqTsGetSFQEntry()
...

> >we're trashing the last 48 bytes of every copy we make.
> >Does this driver even work ?
>
> No, ulDestPtr ist ULONG* so we increase it by sizeof(ULONG)*16 which is 64.

Duh, yes. That is broken on 64-bit however, where it will advance 128 bytes
instead of 64 bytes.

Dave