FUJITA Tomonori wrote: >>>> FUJITA Tomonori wrote: >>>>>>> I can't see what changing the meaning of rq->data_len (and >>>>>>> investigating all the block drivers) gives us. >>>>>> No matter which way you go, you change the meaning of rq->data_len and >>>>>> you MUST inspect rq->data_len usage whichever way you go. >>>>> The patch doens't change that rq->data_len means the true data >>>>> length. But yeah, it breaks rq->data_len == sum(sg). So it might break >>>>> some drivers. >>>> Yeah, that's what I was saying. You end up breaking one of the two >>>> assumptions. As sglist is getting modified for any driver if it has DMA >>>> alignment set, whether rq->data_len is adjusted together or not, sglist >>>> and data_len usages have to be audited. >>> My patch (well, James' original approach) doesn't affect drivers that >>> don't use drain buffer. rq->data_len still means the true data length >>> and rq->data_len is equal to sum(sg) for them. So right now we need to >>> audit only libata. >> Your patch does change sglist for any driver which sets DMA alignment. > > I overlook it. Where does it changes sglist? At the end of blk_rq_map_user() together with data_len / extra_len mangling or were you talking about James' original patch? -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
