storage: storvsc user-mode implementation #1256
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| struct StorvscInner { | ||
| next_transaction_id: AtomicU64, | ||
| new_request_receiver: Receiver<StorvscRequest>, | ||
| transactions: Mutex<HashMap<u64, PendingOperation>>, |
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I would use a slab::Slab<PendingOperation> instead of a HashMap. The slab will give you a usize key which you can use as the transaction ID.
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I see from the Slab docs that it can reuse keys for removed items. Could there be any issues with reused, non-sequential keys on the storvsp side?
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That would be a protocol violation--storvsp can only send a completion for a transaction once.
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So does slab still work for this if it can reuse keys, given that it can result in duplicate transaction IDs?
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| .to_owned(); | ||
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| // Step 4: CREATE_SUB_CHANNELS (if supported) |
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We don't really support subchannels yet, right?
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Subchannels are seemingly supported by our storvsp implementation.
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Sure but this client doesn't seem to actually do anything with them.
I also don't know if subchannels are supported by the Linux vmbus uio driver.
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(For the use case of accessing low-perf devices, it doesn't matter. But subchannels will be a big deal for high-perf devices.)
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| enum Packet { | ||
| Completion(StorvscCompletionPacket), | ||
| //Data(StorvscDataPacket), |
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I believe this case will be necessary for supporting hot add/remove.
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What would the protocol operations be for hot add/remove?
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The driver get an async notification message that something changed, and then it's supposed to rescan the SCSI bus (if even needs to--in the OpenHCL case, we know what LUN to expect, so we can pretty much just silently drop the notification).
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After doing nothing, then we need to send a completion for the data packet, correct?
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Which commands do we need to support receiving in storvsc? I imagine ENUMERATE_BUS is among them, but are there any others?
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Looking good! |
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Pinging this issue because it still needs reviews |
This is an implementation of the storvsc (client complement to storvsp) for SCSI storage over VMBus.
#273