On Thu, Jul 30, 2020 at 10:05:50AM +0200, Martin Kepplinger wrote: > On 29.06.20 18:15, Alan Stern wrote: > > On Mon, Jun 29, 2020 at 11:42:59AM +0200, Martin Kepplinger wrote: > >> > >> > >> On 26.06.20 17:44, Alan Stern wrote: > >>> Martin's best approach would be to add some debugging code to find out why > >>> blk_queue_enter() isn't calling bkl_pm_request_resume(), or why that call > >>> doesn't lead to pm_request_resume(). > >>> > >>> Alan Stern > >>> > >> > >> Hi Alan, > >> > >> blk_queue_enter() always - especially when sd is runtime suspended and I > >> try to mount as above - sets success to be true for me, so never > >> continues down to bkl_pm_request_resume(). All I see is "PM: Removing > >> info for No Bus:sda1". > > > > Aha. Looking at this more closely, it's apparent that the code in > > blk-core.c contains a logic bug: It assumes that if the BLK_MQ_REQ_PREEMPT > > flag is set then the request can be issued regardless of the queue's > > runtime status. That is not correct when the queue is suspended. > > > > Below is my attempt to fix this up. I'm not sure that the patch is > > entirely correct, but it should fix this logic bug. I would appreciate a > > critical review. > > > > Martin, does this fix the problem? > > > > Alan Stern > > Hi Alan, > > So in the block layer your change below indeed fixes the problem and if > you want to submit that 1:1 feel free to add > > Tested-by: Martin Kepplinger <martin.kepplinger@xxxxxxx> > > thanks for your help in this! Thank you for _your_ help! The next merge window is coming up soon. I think I'll wait until it is over before submitting the patch (maintainers tend to be too busy to consider new patches during a merge window). But I am still open to comments or criticism of the patch in the meantime. There hasn't been any feedback since Bart's initial set of questions. Alan Stern
