When an I/O gets an I/O error, the I/O path to which the I/O was
submitted may be still available. In this case, the I/O should be
retried to the same I/O path. However, a new I/O path was always
selected for an I/O retry.
For the active/passive policy, the same I/O path was selected naturally.
However, for the active/active policy, it was very likely that a
different I/O path was selected.
To use the same I/O path for an I/O retry, add a helper function
bdev_nvme_retry_io() into bdev_nvme_retry_ios() and replace
bdev_nvme_submit_request() by bdev_nvme_retry_io(). bdev_nvme_retry_io()
checks if nbdev_io->io_path is not NULL and is available. Then, call
_bdev_nvme_submit_request() if true, or call bdev_nvme_submit_request()
otherwise. For I/O path error, clear nbdev_io->io_path for
clarification. Add unit test to verify this change.
Linux kernel native NVMe multipath already takes this approach. Hence,
this change will be reasonable.
Signed-off-by: Shuhei Matsumoto <smatsumoto@nvidia.com>
Change-Id: I7022aafd8b1cdd5830c4f743d64b080aa970cf8d
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/16015
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@nvidia.com>
Reviewed-by: Richael <richael.zhuang@arm.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
ae620784bd