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IO a manager Kernel APC

0mWindyBug0mWindyBug Member Posts: 29
edited November 2023 in NTDEV
Noob question here!
Why does the IO manager need to queue an apc to complete an IO request (copy system buffer to requestor buffer / return status etc?)
I’ve read it’s that way only for asynchronous IO, Initially my guess was its to make sure the requestor thread is currently scheduled before copying the system buffer to the virtual requestor buffer . That would make sense for Asynchronous IO , but wouldn’t it also be make sense for synchronous IO? Other than the dispatch routine at the top of the device stack MSDN suggests dispatch routines may run in arbitrary thread context, so doesn’t that suggest even for Synchronous IO apc is needed ? What’s the actual purpose of the Apc ? I guess I got it wrong

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