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I am trying to speed up a cross-platform Software Raid (RAID5) driver in WDM.
Currently, my method is to split the incoming IO into stripe sized chunks, allocate a parity buffer, compute the parity, and write stripe sized data to the individual disks. This unfortunately results in a large number of IO if the incoming buffer is large.
I was looking into scatter/gather lists and want to see if this approach is possible?
IoGetDmaAdapter for the member disks. Currently, I am calling this from the completion routine of an
I tried calling
IoGetDmaAdapter using the PDO I get in my disk filter driver, but I don't get a
_DMA_ADAPTER pointer even after trying several options for
DEVICE_DESCRIPTION as mentioned in earlier OSR posts or in Windows samples. I always end up with a
My PDO has
: kd> !devobj 0xffffa70a`c5c73050 Device object (ffffa70ac5c73050) is for: 00000048 \Driver\storvsc DriverObject ffffa70ac1c6fa10 Current Irp 00000000 RefCount 0 Type 00000007 Flags 00001050 SecurityDescriptor ffffdf80e7e1d8e0 DevExt ffffa70ac5c731a0 DevObjExt ffffa70ac5c74120 DevNode ffffa70ac8608650 ExtensionFlags (0000000000) Characteristics (0x00000180) FILE_AUTOGENERATED_DEVICE_NAME, FILE_DEVICE_SECURE_OPEN AttachedDevice (Upper) ffffa70ac610e060 \Driver\disk Device queue is not busy.
Is my approach feasible? If not, is there another way to execute DMA scatter/gather from my disk filter driver?
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