Messages in this thread | | | Date | Sun, 19 May 2013 16:34:18 +0300 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v2 10/10] kernel: might_fault does not imply might_sleep |
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On Sun, May 19, 2013 at 08:34:04AM -0400, Steven Rostedt wrote: > On Sun, 2013-05-19 at 12:35 +0300, Michael S. Tsirkin wrote: > > > No, I was not assuming that. What I'm trying to say is that a caller > > that does something like this under a spinlock: > > preempt_disable > > pagefault_disable > > error = copy_to_user > > pagefault_enable > > preempt_enable_no_resched > > > > is not doing anything wrong and should not get a warning, > > as long as error is handled correctly later. > > Right? > > > > What I see wrong with the above is the preempt_enable_no_resched(). The > only place that should be ever used is right before a schedule(), as you > don't want to schedule twice (once for the preempt_enable() and then > again for the schedule itself). > > Remember, in -rt, a spin lock does not disable preemption. > > -- Steve
Right but we need to keep it working on upstream as well. If I do preempt_enable under a spinlock upstream won't it try to sleep under spinlock?
-- MST
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