cciss: add performant mode support for Stars/Sirius
Add a mode of controller operation called Performant Mode. Even though cciss has been deprecated in favor of hpsa there are new controllers due out next year that HP must support in older vendor distros. Vendors require all fixes/features be upstream. These new controllers support only 16 commands in simple mode but support up to 1024 in performant mode. This requires us to add this support at this late date. The performant mode transport minimizes host PCI accesses by performinf many completions per read. PCI writes are posted so the host can write then immediately get off the bus not waiting for the writwe to complete to the target. In the context of performant mode the host read out to a controller pulls all posted writes into host memory ensuring the reply queue is coherent. Signed-off-by:Mike Miller <mike.miller@hp.com> Cc: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Jens Axboe <jaxboe@fusionio.com>
parent
1d141441
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