Close event with pending IO
in [Device Drivers]
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From: Daniel Knueven on 20 Aug 2008 16:52 Is it possible to get a close event on a device that has outstanding IO requests? If an application tries to close its handle to my driver, I'd like my driver to cancel any pending IO requests and let the app close down instead of hanging. I've added a close event handler with WdfDeviceInitSetFileObjectConfig, but I only get that call when all the IO is complete and the device handle is being closed. I want to get notification even if IO is still pending so I can clean up for the bad app. Thanks, -Daniel
From: Doron Holan [MSFT] on 20 Aug 2008 18:46 you want EvtFileCleanup. Cleanup is called in the context of the app while io is still pending. Close is called onced the ref count of the file object has reached zero which means no more pending io (since each takes a ref on the PFILE_OBJECT when sent). Now, after EvtFileCleanup has been called (or not been set) KMDF will purge/complete all pending io in all of the device's queues for that file handle. if you are still seeing a hang, that means that you are holding on a request (perhaps from a sequential or parallel queue) and not completing it in time. you can be notified that the queues are being purged by registering an EvtIoStop on the queue where you have pended requests and it will be invoked for each request that is still in the queue after a purge d -- Please do not send e-mail directly to this alias. this alias is for newsgroup purposes only. This posting is provided "AS IS" with no warranties, and confers no rights. "Daniel Knueven" <DanielKnueven(a)discussions.microsoft.com> wrote in message news:0924173B-EA44-4CCD-AA66-6DDC40A65B14(a)microsoft.com... > Is it possible to get a close event on a device that has outstanding IO > requests? If an application tries to close its handle to my driver, I'd > like > my driver to cancel any pending IO requests and let the app close down > instead of hanging. I've added a close event handler with > WdfDeviceInitSetFileObjectConfig, but I only get that call when all the IO > is > complete and the device handle is being closed. I want to get notification > even if IO is still pending so I can clean up for the bad app. > > Thanks, > -Daniel
From: Daniel Knueven on 21 Aug 2008 11:51
The cleanup event did the trick. The IO request isn't in the queue when the app tries to close the handle. The IO has already been dequeued to my driver, but the device doesn't have any data yet so it won't complete the read until it has something to complete it with. Since the cleanup call gets made before the IO is complete, it can cancel the IO and that allows the close to complete. Thanks for your help! -Daniel "Doron Holan [MSFT]" wrote: > you want EvtFileCleanup. Cleanup is called in the context of the app while > io is still pending. Close is called onced the ref count of the file object > has reached zero which means no more pending io (since each takes a ref on > the PFILE_OBJECT when sent). Now, after EvtFileCleanup has been called (or > not been set) KMDF will purge/complete all pending io in all of the device's > queues for that file handle. if you are still seeing a hang, that means > that you are holding on a request (perhaps from a sequential or parallel > queue) and not completing it in time. you can be notified that the queues > are being purged by registering an EvtIoStop on the queue where you have > pended requests and it will be invoked for each request that is still in the > queue after a purge > > d > > -- > Please do not send e-mail directly to this alias. this alias is for > newsgroup purposes only. > This posting is provided "AS IS" with no warranties, and confers no rights. > > > "Daniel Knueven" <DanielKnueven(a)discussions.microsoft.com> wrote in message > news:0924173B-EA44-4CCD-AA66-6DDC40A65B14(a)microsoft.com... > > Is it possible to get a close event on a device that has outstanding IO > > requests? If an application tries to close its handle to my driver, I'd > > like > > my driver to cancel any pending IO requests and let the app close down > > instead of hanging. I've added a close event handler with > > WdfDeviceInitSetFileObjectConfig, but I only get that call when all the IO > > is > > complete and the device handle is being closed. I want to get notification > > even if IO is still pending so I can clean up for the bad app. > > > > Thanks, > > -Daniel > > |