Christof Schmitt wrote: > On Tue, Mar 24, 2009 at 10:46:09AM -0700, Mike Anderson wrote: >> Brian King <brking@xxxxxxxxxxxxxxxxxx> wrote: >>> Your assessment sounds correct to me. The other caveat to note is that >>> if for some reason in your eh_abort_handler you don't think the command >>> is still outstanding, you should return SUCCESS for this as well. >>> >>> -Brian >>> >>> Christof Schmitt wrote: >>>> I am investigating what is required from a LLD when SCSI commands time >>>> out and the SCSI EH calls the eh_abort_handler. The documentation in >>>> scsi_eh.txt states: >>>> >>>> <<scsi_eh_abort_cmds>> >>>> >>>> This action is taken for each timed out command. >>>> hostt->eh_abort_handler() is invoked for each scmd. The >>>> handler returns SUCCESS if it has succeeded to make LLDD and >>>> all related hardware forget about the scmd. >>>> >>>> From this and from looking at the code, i would conclude: >>>> >>>> 1) If the LLD returns FAILED from the eh_abort_handler, then the >>>> command is still allowed to be active in the LLD and the LLD can >>>> call scsi_done any time later (probably latest when the >>>> eh_host_reset_handler flushes everything that is still pending). >>>> >>>> 2) While the abort is pending, but before returning SUCCESS from >>>> eh_abort_handler, the LLD can still call scsi_done for the SCSI >>>> command to be aborted (the SCSI command might be returned with a >>>> status "aborted" if the abort succeeds, or "good" if it was >>>> completed just before the abort reached the storage system). >>>> >> In cases 1 and 2 above calling scsi_done can be done but will cause >> the request to be stopped in blk_complete_request >> (scsi_done->blk_complete_request) as the timed out handler has >> already taken ownership of the command. > > I am not too familiar with the blk completion handling. Would calling > scsi_done for the cases above cause any problems? If there are reasons > not to call scsi_done here, then this could be mentioned in the scsi > documentation file. No. There is no requirement to call scsi_done for aborted commands, but there is also no harm in doing so. -Brian -- Brian King Linux on Power Virtualization IBM Linux Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
