On 09/02/13 09:12, Hannes Reinecke wrote:
@@ -353,6 +354,8 @@ void scsi_put_command(struct scsi_cmnd *cmd) list_del_init(&cmd->list); spin_unlock_irqrestore(&cmd->device->list_lock, flags); + cancel_delayed_work(&cmd->abort_work); + __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev); } EXPORT_SYMBOL(scsi_put_command);
Is this approach safe ? Is it e.g. possible that the abort work starts just before the cancel_delayed_work() call and continues to run after scsi_put_command() has finished ? In drivers/scsi/libfc/fc_exch.c a similar issue is solved by holding an additional reference as long as delayed work (fc_exch.timeout_work) is queued.
+void +scmd_eh_abort_handler(struct work_struct *work) +{ + struct scsi_cmnd *scmd = + container_of(work, struct scsi_cmnd, abort_work.work); + struct scsi_device *sdev = scmd->device; + unsigned long flags; + int rtn; + + spin_lock_irqsave(sdev->host->host_lock, flags); + if (scsi_host_eh_past_deadline(sdev->host)) { + spin_unlock_irqrestore(sdev->host->host_lock, flags); + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "scmd %p eh timeout, not aborting\n", scmd)); + } else { + spin_unlock_irqrestore(sdev->host->host_lock, flags); + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "aborting command %p\n", scmd)); + rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd); + if (rtn == SUCCESS) { + scmd->result |= DID_TIME_OUT << 16; + if (!scsi_noretry_cmd(scmd) && + (++scmd->retries <= scmd->allowed)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_WARNING, scmd, + "scmd %p retry " + "aborted command\n", scmd)); + scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY); + } else { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_WARNING, scmd, + "scmd %p finish " + "aborted command\n", scmd)); + scsi_finish_command(scmd); + } + return; + } + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "scmd %p abort failed, rtn %d\n", + scmd, rtn)); + } + + if (scsi_eh_scmd_add(scmd, 0)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_WARNING, scmd, + "scmd %p terminate " + "aborted command\n", scmd)); + scmd->result |= DID_TIME_OUT << 16; + scsi_finish_command(scmd); + } +}
This patch adds several new calls to LLD EH handlers. Is it guaranteed that these will only be invoked before scsi_remove_host() has finished ? For more background information, see also "[PATCH] Make scsi_remove_host() wait until error handling finished" (http://thread.gmane.org/gmane.linux.scsi/82572/focus=82779).
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