On Sun, 03/13 14:37, Huaicheng Li (coperd) wrote: > Hi all, > > What I’m confused about is that: > > If one I/O is too large and may need several rounds (say 2) of DMA transfers, > it seems the second round transfer begins only after the completion of the > first part, by reading data from **IDEState**. But the IDEState info may have > been changed by VCPU threads (by writing new I/Os to it) when the first > transfer finishes. From the code, I see that IDE r/w call back function will > continue the second transfer by referencing IDEState’s information. Wouldn’t > this be problematic? Am I missing anything here?
Can you give an concrete example? I/O in VCPU threads that changes IDEState must also take care of the DMA transfers, for example ide_reset() has blk_aio_cancel and clears s->nsectors. If an I/O handler fails to do so, it is a bug. Fam
