I am agree with you. There are researchers who cites the papers of particular journals for getting their work published in that journal. Some journals encourages to do so. However, reputed publishers always look into the same. Also, they check the appropriateness of a cited work. This is a generic issue and continuing from long time.

Thanks for your opinions Shirshendu Roy. I think, there is a high number of citation which can be evaluated in the scope of "citation farm". So, the scope of citation farming seems broader. I understand the term "citation farm" as "Unnatural and not driven by scientific research processes citation".

Concerning the self-citation issue. Sometimes it is easy to see when reviewing a paper that an author is trying to give hime/herself an unmotivated number of self-citations (and thereby revealing identity). Why not try to establish a practice among journals to limit self-citations to three citations per author in a paper? That should be enough in most cases.