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>> __u64 __pad2[1]; >> }; >> + struct { >> + __u64 attr_ptr; /* pointer to attribute information */ >> + __u64 attr_type_mask; /* bit mask of attributes */ >> + }; > > I can't say I'm a fan of how this turned out. I'm merging up the write > hint stuff, and these new fields occupy where that 16-bit value was > initially going. Okay, so I guess I need to just add a new attribute > flag? That might work if I am only appending exactly one extra attribute > per SQE, but what if I need both PI and Write Hint? Do the attributes > need to appear in a strict order? We'll definitely need to be able to include multiple attributes. Not sure how the attr_type_mask was intended to work. I guess parsing attributes based on bit position in the mask would be one option. The SCSI approach would be for each attribute to have a 4-byte header with a type and a length so multiple attributes can be described by a single buffer. FWIW, I wasn't initially a big fan of having the attrs stored outside of the sqe but it actually made things a lot cleaner for my use case. -- Martin K. Petersen Oracle Linux Engineering