>are completly 2 different stories. Even driver don’t support any IRP asynchronous processing, the
user mode asynchronous is also supported, becase the support just comes from OS.
Not so.
If the driver always blocks in the dispatch path and then completes the IRP in it without pending - then it kills overlapped IO on its handles.
In such a case, even though the overlapped IO from user will still work, it will lose its important behavior of “returning from read/write/IOCTL syscall ASAP”. Instead, it will always block till the very completion.
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Maxim S. Shatskih
Microsoft MVP on File System And Storage
xxxxx@storagecraft.com
http://www.storagecraft.com