Here is a short excerpt of the semantic patch performing
this transformation:
(http://www.emn.fr/x-info/coccinelle/)

//<smpl>
@@
expression E1,E2,E3;
@@
- kzalloc(E1*sizeof(E2),E3)
+ kcalloc(E1,sizeof(E2),E3)

@@
expression E1,E3;
type T;
@@
- kzalloc(E1*sizeof(T),E3)
+ kcalloc(E1,sizeof(T),E3)
//</smpl>
Signed-off-by: NNicolas Palix <npalix@diku.dk>
Cc: Hank Janssen <hjanssen@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>