On 27/09/17 02:42, Linus Walleij wrote: > On Fri, Sep 22, 2017 at 2:36 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > >> Until mmc has blk-mq support fully implemented and tested, add a >> parameter use_blk_mq, default to false unless config option MMC_MQ_DEFAULT >> is selected. >> >> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> > >> +config MMC_MQ_DEFAULT >> + bool "MMC: use blk-mq I/O path by default" >> + depends on MMC && BLOCK > > I would say: > default y > > Why not. SCSI is starting to enable this by default so IMO we should SCSI didn't manage it yet. > not take the > intermediate step of having this as optional. Otherwise it never gets tested. The argument that we don't have to take any responsibility for getting things tested is a poor one. Anyway, you can always send a patch later to change the default, so why the hurry to do it now? > > Set it to default y and after two kernel releases, if nothing happens, we simply > delete the old block layer path. > >> +#ifdef CONFIG_MMC_MQ_DEFAULT >> +bool mmc_use_blk_mq = true; >> +#else >> +bool mmc_use_blk_mq = false; >> +#endif >> +module_param_named(use_blk_mq, mmc_use_blk_mq, bool, S_IWUSR | S_IRUGO); > > Are people really modprobing this so it needs to be a module parameter? Irrespective of modprobe, the parameter can be changed without re-compiling. > > Maybe I'm the only developer stupid enough to just recompile and reboot Just change the parameter and unbind and rebind the host controller.
