Google Linux servers hit with $5m patent infringement verdict (The Register)

Note, however, that the essential claims of '120 all involve the access to a linked list of same-hash records as part of the by-key record access mechanism and cleaning out at least some of the expired records on that list while doing so.

You should consult the text of U.S. Patent 5,893,120 to satisfy yourself one way or the other. It is found at http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&...

Also, you will need to look at the TIFF images for the code, flowcharts, and especially for the modifications made to the claims as part of a reexamination amendment that was issued on 2011-04-12. (The reexamination determination is on the last page. It modifies 4 of the 8 claims and adds 4 more.)