On Fri, 2018-08-10 at 09:51 +-0800, jianchao.wang wrote: +AD4- On 08/10/2018 03:41 AM, Bart Van Assche wrote: +AD4- +AD4- +- +AD4- +AD4- +- blk+AF8-set+AF8-pm+AF8-only(q)+ADs- +AD4- +AD4- +- /+ACo- +AD4- +AD4- +- +ACo- This function only gets called if the most recent +AD4- +AD4- +- +ACo- pm+AF8-request+AF8-resume() call occurred at least autosuspend+AF8-delay+AF8-ms +AD4- +AD4- +- +ACo- ago. Since blk+AF8-queue+AF8-enter() is called by the request allocation +AD4- +AD4- +- +ACo- code before pm+AF8-request+AF8-resume(), if no requests have a tag assigned +AD4- +AD4- +- +ACo- it is safe to suspend the device. +AD4- +AD4- +- +ACo-/ +AD4- +AD4- +- ret +AD0- -EBUSY+ADs- +AD4- +AD4- +- if (blk+AF8-requests+AF8-in+AF8-flight(q) +AD0APQ- 0) +AHs- +AD4- +AD4- +- /+ACo- +AD4- +AD4- +- +ACo- Call synchronize+AF8-rcu() such that later blk+AF8-queue+AF8-enter() +AD4- +AD4- +- +ACo- calls see the preempt-only state. See also +AD4- +AD4- +- +ACo- +AD4- +AD4- https://urldefense.proofpoint.com/v2/url?u+AD0-http-3A+AF8AXw-lwn.net+AF8-Articles+AF8-573497+AF8AJg-d+AD0-DwIBAg+ACY-c+AD0-RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI+AF8-JnE+ACY-r+AD0-7WdAxUBeiTUTCy8v-7zXyr4qk7sx26ATvfo6QSTvZyQ+ACY-m+AD0-U9uPCJD2WnkXvdzrWaKPh2wJuk8-IHvxZ9sWDVrg2Tg+ACY-s+AD0-c9E23TPCpNQkiZpuzGztwHxjWF8qrESfRnPmI-e-Z48+ACY-e+AD0- +AD4- +AD4- . +AD4- +AD4- +- +ACo-/ +AD4- +AD4- +- synchronize+AF8-rcu()+ADs- +AD4- +AD4- +- if (blk+AF8-requests+AF8-in+AF8-flight(q) +AD0APQ- 0) +AD4- +AD4- +- ret +AD0- 0+ADs- +AD4- +AD4- +- +AH0- +AD4- +AD4- I still think blk+AF8-set+AF8-pm+AF8-only should be moved after blk+AF8-requests+AF8-in+AF8-flight. +AD4- Otherwise, the normal IO will be blocked for a little while if there are still +AD4- busy requests. Hi Jianchao, Although I think it is unlikely that the scenario you described will happen, I will make the change you requested. Bart.
