On Tue, Aug 29, 2017 at 12:29:35PM -0700, Joe Perches wrote: > On Wed, 2017-08-30 at 00:19 +0530, Himanshu Jha wrote: > > drivers/scsi/megaraid/megaraid_sas_fusion.c > > I don't know if you did this with coccinelle.
Yes, I did this with coccinelle. > > If so, it would be good to show the tool and script > in the commit message. Alright, next time. > > If not, the input script is pretty simple. > > $ cat memset_before_memcpy.cocci > @@ > expression e1; > expression e2; > expression e3; > @@ > > - memset(e1, 0, e3); > memcpy(e1, e2, e3); > $ > > Adding a test to make sure e1 or e3 isn't > modified before any other code uses them > by doing > > $ cat memset_before_memcpy_2.cocci > @@ > expression e1; > expression e2; > expressi > on e3; > @@ > > - memset(e1, 0, e3); > ... when != \( e1 \| e3 \) > memcpy(e1, e2, e3); > $ > > finds more cases but there may be a > false positive if e1 is a passed > function argument and if the operation > isn't effectively atomic like below: > I usually check all my diff before sending to see if any false positives occured or not. It's been 4 days since I learnt coccinelle and before I used to look into every files for occurences or search the identifiers on FreeElectrons. >From now I will mention whatever tool I used on my patch! Thanks > ---------------------------------------------------------------- > --- a/net/bridge/br_multicast.c > +++ b/net/bridge/br_multicast.c > @@ -2556,7 +2556,6 @@ void br_multicast_get_stats(const struct > struct br_mcast_stats tdst; > int i; > > - memset(dest, 0, sizeof(*dest)); > if (p) > stats = p->mcast_stats; > else > > ---------------------------------------------------------------- > > where the memcpy is the last line of the function. >
