Red Hat Bugzilla – Bug 682265
[RHEL 6] libsas: flush initial device discovery before completing ->scan_finished()
Last modified: 2011-05-19 08:00:32 EDT
It is possible that all initial discovery events have not completed during scsi scan, DISCE_DISCOVER_DOMAIN events are queued up in sas_form_port while processing the PORTE_BYTES_DMAED events. Posted upstream: http://marc.info/?l=linux-scsi&m=129791077719331&w=2 During initial scan libsas drivers start their phys and notify libsas with PORTE_BYTES_DMAED events as port links are established. This notification in turn causes libsas to post DISCE_DISCOVER_DOMAIN events to the queue. Calling scsi_flush_work() at the end of scan_finished guarantees that all preceding PORTE_BYTES_DMAED events have been registered in the queue, but it does not guarantee that the resulting DISCE_DISCOVER_DOMAIN events have been processed because flush_workqueue() explicitly avoids live-locking with incoming work. Introduce sas_flush_discovery() to guarantee that all initial discovery events have completed. It is called after the driver determines all initial PORTE_BYTES_DMAED events have had a chance to enter the queue. This does not cover BCNs that are generated during expander bring up, only the initial sas_discover_domain() event.
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release.
Patch(es) available on kernel-2.6.32-130.el6
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2011-0542.html