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由 Christoph Hellwig 提交于
This adds an abstraction that allows ULPs to simply pass a completion object and completion callback with each submitted WR and let the RDMA core handle the nitty gritty details of how to handle completion interrupts and poll the CQ. In detail there is a new ib_cqe structure which just contains the completion callback, and which can be used to get at the containing object using container_of. It is pointed to by the WR and WC as an alternative to the wr_id field, similar to how many ULPs already use the field to store a pointer using casts. A driver using the new completion callbacks allocates it's CQs using the new ib_create_cq API, which in addition to the number of CQEs and the completion vectors also takes a mode on how we poll for CQEs. Three modes are available: direct for drivers that never take CQ interrupts and just poll for them, softirq to poll from softirq context using the to be renamed blk-iopoll infrastructure which takes care of rearming and budgeting, or a workqueue for consumer who want to be called from user context. Thanks a lot to Sagi Grimberg who helped reviewing the API, wrote the current version of the workqueue code because my two previous attempts sucked too much and converted the iSER initiator to the new API. Signed-off-by: NChristoph Hellwig <hch@lst.de>
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