Mike Christie wrote: > On 10/13/2010 06:42 AM, Hannes Reinecke wrote: >> >> fc_block_scsi_eh() might return with status FAST_IO_FAIL >> indicating I/O has been terminated due to fast_io_fail timeout. >> In this case the rport is still blocked, so any error recovery >> will be failing on this port. >> Hence each driver needs to check if the return value from >> fc_block_scsi_eh() is something other than SUCCESS, in which >> case it should just return with that status. >> And we need to update the error handler to deal with a >> status of FAST_IO_FAIL, too. >> And fc_block_scsi_eh() should return SUCCESS on success, >> not 0. Otherwise the calling routine will become confused >> when reusing that value. >> > > Is this patch supposed to fix the problem I described or is there more > patches to follow or do you think I am being too paranoid? It seems the > patch alone is going to make the problem worse in the drivers you are > speeding up failure in. In the drivers now checking fc_block_scsi_eh and > returning when fast io fail is returned then the scsi eh > scsi_eh_flush_done_q's scsi_finish_command/scsi_queue_insert processing > is going to get done faster and more likely to conflict with the > termiante_rport_io callback processing, right? No, this patch does _not_ fix the race you've described, it just fixes the problem of fc_block_scsi_eh() returning FAST_IO_FAIL, which screws the error handler in drivers not checking the return value. So it's partially covered by your patchset. However, in your patchset you're missing two issues: - The current implementation of fc_block_scsi_eh() return '0' on success. This screws over drivers which re-uses this value; check eg. lpfc_abort_handler(). So we should be returning 'SUCCESS' here. - scsi_error needs to be fixed up to handle FAST_IO_FAIL. Any of the functions called from scsi_abort_eh_cmnd() can return FAST_IO_FAIL, in which case escalating to the next function becomes pointless. I guess it would make sense to merge these two patchsets, either having two patchsets (one for the FAST_IO_FAIL changes and one for the rport race) or indeed merge them both into one. I'm okay with either of it. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Markus Rex, HRB 16746 (AG Nürnberg) -- 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
