On Thu, Dec 21 2006, Mike Christie wrote: > Jens Axboe wrote: > > On Thu, Dec 21 2006, Mike Christie wrote: > >> Or the block layer code could set up the clone too. elv_next_request > >> could prep a clone based on the orignal request for the driver then dm > >> would not have to worry about that part. > > > > It really can't, since it doesn't know how to allocate the clone > > request. I'd rather export this functionality as helpers. > > > > What do you think about dm's plan to break up make_request into a > mapping function and in to the part the builds the bio into a request. > This would fit well with them being helpers and being able to allocate > the request from the correct context. I think it sounds promising! dm probably still needs its own mempool for request allocation, but that should be doable. > I see patches for that did not get posted, but I thought Joe and > Alasdair used to talk about that a lot and in the dm code I think there > is sill comments about doing it. Maybe the dm comments mentioned the > merge_fn, but I guess the merge_fn did not fit what they wanted to do or > something. I think Alasdair talked about this at one of his talks at OLS > or it was in a proposal for the kernel summit. I can dig up the mail if > you want. Not sure I remember the details of that one, so the mail/thread might be useful. -- Jens Axboe -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
