Want to apply just a part of your patch(Only on few files or even a few lines)?

Starting tag = MY_PORTION_START
Ending tag = MY_PORTION_END

awk 'BEGIN {start=0} /MY_PORTION_END/ {start=0} {if (start == 1) print} /MY_PORTION_START/ {start=1}' patch.diff | patch -p 1

You have to insert these tags into your patch file depends on your need.