[SCSI] libsas: close error handling vs sas_ata_task_done() race
Since sas_ata does not implement ->freeze(), completions for scmds and internal commands can still arrive concurrent with ata_scsi_cmd_error_handler() and sas_ata_post_internal() respectively. By the time either of those is called libata has committed to completing the qc, and the ATA_PFLAG_FROZEN flag tells sas_ata_task_done() it has lost the race. In the sas_ata_post_internal() case we take on the additional responsibility of freeing the sas_task to close the race with sas_ata_task_done() freeing the the task while sas_ata_post_internal() is in the process of invoking ->lldd_abort_task(). Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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committed by
James Bottomley

parent
e500a34b02
commit
3dff5721e4
@@ -956,49 +956,6 @@ void sas_shutdown_queue(struct sas_ha_struct *sas_ha)
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spin_unlock_irqrestore(&core->task_queue_lock, flags);
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}
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/*
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* Call the LLDD task abort routine directly. This function is intended for
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* use by upper layers that need to tell the LLDD to abort a task.
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*/
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int __sas_task_abort(struct sas_task *task)
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{
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struct sas_internal *si =
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to_sas_internal(task->dev->port->ha->core.shost->transportt);
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unsigned long flags;
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int res;
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spin_lock_irqsave(&task->task_state_lock, flags);
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if (task->task_state_flags & SAS_TASK_STATE_ABORTED ||
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task->task_state_flags & SAS_TASK_STATE_DONE) {
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spin_unlock_irqrestore(&task->task_state_lock, flags);
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SAS_DPRINTK("%s: Task %p already finished.\n", __func__,
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task);
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return 0;
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}
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task->task_state_flags |= SAS_TASK_STATE_ABORTED;
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spin_unlock_irqrestore(&task->task_state_lock, flags);
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if (!si->dft->lldd_abort_task)
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return -ENODEV;
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res = si->dft->lldd_abort_task(task);
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spin_lock_irqsave(&task->task_state_lock, flags);
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if ((task->task_state_flags & SAS_TASK_STATE_DONE) ||
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(res == TMF_RESP_FUNC_COMPLETE))
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{
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spin_unlock_irqrestore(&task->task_state_lock, flags);
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task->task_done(task);
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return 0;
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}
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if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
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task->task_state_flags &= ~SAS_TASK_STATE_ABORTED;
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spin_unlock_irqrestore(&task->task_state_lock, flags);
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return -EAGAIN;
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}
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/*
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* Tell an upper layer that it needs to initiate an abort for a given task.
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* This should only ever be called by an LLDD.
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@@ -1097,7 +1054,6 @@ EXPORT_SYMBOL_GPL(sas_slave_configure);
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EXPORT_SYMBOL_GPL(sas_change_queue_depth);
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EXPORT_SYMBOL_GPL(sas_change_queue_type);
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EXPORT_SYMBOL_GPL(sas_bios_param);
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EXPORT_SYMBOL_GPL(__sas_task_abort);
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EXPORT_SYMBOL_GPL(sas_task_abort);
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EXPORT_SYMBOL_GPL(sas_phy_reset);
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EXPORT_SYMBOL_GPL(sas_phy_enable);
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