tree 870dc908379694e20ea319ba11c81bec5864cef7
parent 4cc09e2dc4cbe6009c935b6f12a8376f09124bc5
author Keith Busch <keith.busch@intel.com> 1396565123 -0600
committer Matthew Wilcox <matthew.r.wilcox@intel.com> 1397164319 -0400

NVMe: Retry failed commands with non-fatal errors

For commands returned with failed status, queue these for resubmission
and continue retrying them until success or for a limited amount of
time. The final timeout was arbitrarily chosen so requests can't be
retried indefinitely.

Since these are requeued on the nvmeq that submitted the command, the
callbacks have to take an nvmeq instead of an nvme_dev as a parameter
so that we can use the locked queue to append the iod to retry later.

The nvme_iod conviently can be used to track how long we've been trying
to successfully complete an iod request. The nvme_iod also provides the
nvme prp dma mappings, so I had to move a few things around so we can
keep those mappings.

Signed-off-by: Keith Busch <keith.busch@intel.com>
[fixed checkpatch issue with long line]
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>