Date: Fri, 7 Nov 2014 05:07:59 +0530 From: Sibananda Sahu <sibananda.sahu@avagotech.com> To: freebsd-scsi@freebsd.org Subject: Query regarding Unmapped IO, PIM_UNMAPPED and bus_dmamap_load_ccb() Message-ID: <b27d51d8c4bd9b42ce90b82d1cbf9845@mail.gmail.com>
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Hi All, I have raised this query regarding the following mail: https://lists.freebsd.org/pipermail/freebsd-scsi/2014-July/006407.html Where Alexander Motin talks of Unmapped I/O. As per his direction I have declared the below statement in my driver code: ccb->cpi.hba_misc = PIM_NOBUSRESET | PIM_UNMAPPED; Before enabling PIM_UNMAPPED I was getting the (ccb->ccb_h.flags & CAM_DATA_MASK) as CAM_DATA_VADDR and handling accordingly. But after enabling PIM_UNMAPPED in cpi.hba_misc I am getting the (ccb->ccb_h.flags & CAM_DATA_MASK) as CAM_DATA_BIO and handling the data that comes with bus_dma_load_ccb(). I just did the same thing according to the mps(4) driver as referred by Alexander Motin. So I just wanted to know what exactly happening when I am enabling the PIM_UNMAPPED in the cpi.hba_misc field. And what the CAM_DATA_BIO really means in the CAM_DATA_MASK. It would be great idea if somebody explains what exactly happening or at least give me some references where can I have a look and move forward. Thanks, Sibananda Sahu
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