On Mon, Sep 10, 2012 at 04:01:01PM -0700, Tejun Heo wrote: > Hello, > > On Mon, Sep 10, 2012 at 3:50 PM, Alasdair G Kergon <agk@xxxxxxxxxx> wrote: > >> > Note that this doesn't do anything for allocation from other mempools. > > > > Note that dm has several cases of this, so this patch should not be used with > > dm yet. Mikulas is studying those cases to see whether anything like this > > might be feasible/sensible or not. > > IIUC, Kent posted a patch which converts all of them to use front-pad > (there's no reason not to, really). This better come after that but > it's not like this is gonna break something which isn't broken now. Not all, I only did the easy one - you know how dm has all those crazy abstraction layers? They've got multiple per bio allocations because of that; the core dm code does one, and then some other code takes that struct dm_io* and allocates its own state pointing to that (which then points to the original bio...) So front_pad should still work, but you need to have say dm_crypt pass the amount of front pad it needs to the core dm code when it creates the bio_set, and then dm crypt can use container_of(struct dm_io) and embed like everything does that use the bio_set front pad. *I'm probably misremembering all the names. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
