Date: Sun, 25 Apr 2010 12:20:48 +0900 From: YONETANI Tomokazu <qhwt+fbsd@les.ath.cx> To: freebsd-hackers@freebsd.org Subject: BIO_FLUSH and ips(4) Message-ID: <20100425032047.GA89136@les.ath.cx>
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Hello. The ServeRAID driver, or ips(4), seems to distinguish read or write requests with a macro called ips_read_request(), which is defined as #define ips_read_request(iobuf) ((iobuf)->bio_cmd == BIO_READ) in its strategy routine and a few other places. So when the request is BIO_FLUSH, the ips driver issues a write command (IPS_WRITE_CMD) with length == 0, right? My question is, do ServeRAID controllers treat 0-byte write command as a sync-to-disk request, or is there any command for that purpose? There's a command called IPS_CACHE_FLUSH_CMD defined in ipsreg.h, but it's not used anywhere in the normal code path. Best regards, YONETANI Tomokazu.
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