Re: [PATCH v4 0/8] Support for Open-Channel SSDs

From: Matias Bjorling
Date: Wed Jun 17 2015 - 14:04:21 EST

I don't think the current abuses of the block API are acceptable though.
The crazy deep merging shouldn't be too relevant for SSD-type devices
so I think you'd do better than trying to reuse the TYPE_FS level
blk-mq merging code. If you want to reuse the request
allocation/submission code that's still doable.

As a start add a new submit_io method to the nvm_dev_ops, and add
an implementation similar to pscsi_execute_cmd in
drivers/target/target_core_pscsi.c for nvme, and a trivial no op
for a null-nvm driver replacing the null-blk additions. This
will give you very similar behavior to your current code, while
allowing to drop all the hacks in the block code. Note that simple
plugging will work just fine which should be all you'll need.

Thanks, I appreciate you taking the time to go through it. I'll respin the patches and remove the block hacks.
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