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Commit 2aa8f5d6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Tejun Heo
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libata: only call ->done once all per-tag ressources are released 



When calling ->done before releasing resources we could run into a
race where the SCSI midlayer sends another command and races with
the resources beeing manipulated.  For libata this can't currently
happen as synchronization happens at a higher level, but I'd still
like to fix it to future proof libata and to avoid copy & paste
into SCSI drivers where this pattern has led to reproducible crashes.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 25c7ce7f

drivers/ata/libata-scsi.c

+13 −9
Original line number Diff line number Diff line
@@ -1757,6 +1757,15 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc) 
	return 1;

}



static void ata_qc_done(struct ata_queued_cmd *qc)

{

	struct scsi_cmnd *cmd = qc->scsicmd;

	void (*done)(struct scsi_cmnd *) = qc->scsidone;



	ata_qc_free(qc);

	done(cmd);

}



static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)

{

	struct ata_port *ap = qc->ap;
@@ -1784,9 +1793,7 @@ static void ata_scsi_qc_complete(struct ata_queued_cmd *qc) 
	if (need_sense && !ap->ops->error_handler)

		ata_dump_status(ap->print_id, &qc->result_tf);



	qc->scsidone(cmd);



	ata_qc_free(qc);

	ata_qc_done(qc);

}



/**
@@ -2588,8 +2595,7 @@ static void atapi_sense_complete(struct ata_queued_cmd *qc) 
		ata_gen_passthru_sense(qc);

	}



	qc->scsidone(qc->scsicmd);

	ata_qc_free(qc);

	ata_qc_done(qc);

}



/* is it pointless to prefer PIO for "safety reasons"? */
@@ -2684,8 +2690,7 @@ static void atapi_qc_complete(struct ata_queued_cmd *qc) 
			qc->dev->sdev->locked = 0;



		qc->scsicmd->result = SAM_STAT_CHECK_CONDITION;

		qc->scsidone(cmd);

		ata_qc_free(qc);

		ata_qc_done(qc);

		return;

	}
@@ -2729,8 +2734,7 @@ static void atapi_qc_complete(struct ata_queued_cmd *qc) 
		cmd->result = SAM_STAT_GOOD;

	}



	qc->scsidone(cmd);

	ata_qc_free(qc);

	ata_qc_done(qc);

}

/**

 *	atapi_xlat - Initialize PACKET taskfile