[PATCH libdrm 4/8] xf86drmSL: Fix neighbour printing

[Jan Vesely]

On Fri, 2015-03-20 at 14:01 -0400, Jan Vesely wrote:
> On Fri, 2015-03-20 at 17:38 +0000, Emil Velikov wrote:
> > On 27/02/15 18:07, Jan Vesely wrote:
> > > Signed-off-by: Jan Vesely <jan.vesely at rutgers.edu>
> > > ---
> > >  xf86drmSL.c | 7 +++++--
> > >  1 file changed, 5 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/xf86drmSL.c b/xf86drmSL.c
> > > index acddb54..2160bb8 100644
> > > --- a/xf86drmSL.c
> > > +++ b/xf86drmSL.c
> > > @@ -266,11 +266,14 @@ int drmSLLookupNeighbors(void *l, unsigned long key,
> > >      SkipListPtr   list = (SkipListPtr)l;
> > >      SLEntryPtr    update[SL_MAX_LEVEL + 1];
> > >      int           retcode = 0;
> > > +    SLEntryPtr    entry;
> > > +
> > > +    entry = SLLocate(list, key, update);
> > >  
> > >      *prev_key   = *next_key   = key;
> > >      *prev_value = *next_value = NULL;
> > > -	
> > > -    if (update[0]) {
> > > +
> > > +    if (entry && update[0]) {
> > From a very brief look at git log, the entry check should not be needed.
> > Must admit that I've not looked at all in the implementation of either
> > SLLocate or drmSLLookupNeighbors.
> 
> SLLocate might return early and leave the array uninitialized. All other
> calls to it check the return value. I guess the warning that the
> previous commit tried to fix was "set-but-unused" variable.

I take this back. You were right. SLLocate might return NULL in
non-failing case, and we cannot rely on the return value. I'll post an
updated patch (and a move to tests) shortly

jan

> 
> > 
> > That said it seems that none of the three files
> > (xf86drm{SL,Hash,Random}) has been build as a program for a while. Maybe
> > we could split it out as a standalone test and let it churn at make
> > check time ?
> 
> Sounds like a good idea. I'll try to take a look when time permits, but
> I'd leave that as a separate patch.
> 
> thanks,
> jan
> 
> > 
> > Cheers,
> > Emil
> 

-- 
Jan Vesely <jan.vesely at rutgers.edu>
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