[PATCH] nvme-core: fix io interrupt when work with dm-multipah

[Christoph Hellwig]

On Mon, Jul 27, 2020 at 01:58:18PM +0800, Chao Leng wrote:
> The protocol NVM-Express-1.4 define:
> Command Interrupted: Command processing was interrupted and the
> controller is unable to successfully complete the command. The host
> should retry the command. If this status code is returned, then
> the controller shall clear the Do Not Retry bit to ‘0’ in the Status
> field of the CQE (refer to Figure 124). The controller shall not return
> this status code unless the host has set the Advanced Command Retry
> Enable (ACRE) field to 1h in the Host Behavior Support feature(refer to
> section 5.21.1.22).
> 
> According the protocol define, NVME_SC_CMD_INTERRUPTED need retry.
> The error code NVME_SC_CMD_INTERRUPTED should not translate to
> BLK_STS_TARGET, because if the error code translate to BLK_STS_TARGET,
> dm-multipah will return error to application. So if target return error
> code NVME_SC_CMD_INTERRUPTED, io will interrupt. NVME_SC_CMD_INTERRUPTED
> should translate to BLK_STS_IOERR by default, dm-multipath will fail
> over to other path retry the io.

IOERR still seems wrong, though.