Messages in this thread | | | Subject | RE:(2) [PATCH] driver/nvme/host: Support duplicated nsid for the private | From | Sungup Moon <> | Date | Mon, 14 Mar 2022 18:17:55 +0900 |
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Thank you for your reply,
> > On Mon, Mar 14, 2022 at 04:05:05PM +0900, Sungup Moon wrote: > > When the multi-controller, managed by a special admin command, has private > > namespace with same nsid, current linux driver raise "Duplicate unshared > > namespace" error. But, NVMe Specification defines the NSID usage like this: > > > > If Namespace Management, ANA Reporting, or NVM Sets are supported, the > > NSIDs shall be unique within the NVM subsystem. If the Namespace > > Management, ANA Reporting, and NVM Sets are not supported, then NSIDs: > > a) for shared namespace shall be unique; and > > b) for private namespace are not required to be unique. > > (reference: 6.1.6 NSID and Namespace Usage; NVM Express 1.4c spec) > > > > So, if a multi-controller, which is not managed by Namespace Management > > function, creates some private namespaces without ANA and NVM Sets, the > > duplicated NSID should be allowed because that is not a NVMe specification > > violation. > > > > But, current nvme driver checks only namespace is shared or not, so I > > propose following patch: > > 1. nvme_ctrl has unique_nsid field to identify that controller should > > assign unique nsid. > > 2. nvme_init_ns_head function creates new nvme_ns_head instance not only > > head is null but controller's unique_nsid is false (no flagged > > attribute) and namespace is not shared. > > 3. for creating bdev device file, nvme_mpath_set_disk_name will return > > false when unique_nsid is false and namespace is not shared. > > 4. also, nvme_mpath_alloc_disk alto return 0 with same manner. > > From a very quick glance this looks good. But please make sure you don't > spill over 80 charactes per line.
I checked changes using "scripts/checkpatch.pl --terse --file {changed file}", but there is no warning on my changes. However I will recheck the spill-over lines over 80 characters.
> Also I think instead of adding the > unique_nsid field a little helper that checks the relevant flags might > be a lіttle nicer. It is not checked in a fast path anywere and the > checks are pretty trivial. >
Thank you for your advise! I will remove flag and add checking function for unique nsid.
Thank you, Sungup Moon
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