K 10 svn:author V 3 mav K 8 svn:date V 27 2011-04-19T16:23:07.751080Z K 7 svn:log V 502 MFC r220412, r220414, r220454, r220618, r220814: - Make ada(4) driver to control device write cache, same as ata(4) does. Add kern.cam.ada.write_cache sysctl/tunable to control it alike hw.ata.wc. - Add kern.cam.ada.X.write_cache tunables/sysctls to control write caching on per-device basis. - While adding support for per-device sysctls, merge from graid branch support for ADA_TEST_FAILURE kernel option, which opens few more sysctl, allowing to simulate read and write errors for testing purposes. END