[PATCH] libata: Clear ATA_QCFLAG_ACTIVE flag before calling the completion callback

Description:
  After calling the completion callback, the libata error handler might be
running and getting atapi sense data. Clearing the ATA_QCFLAG_ACTIVE flag
at this point might interfere with the libata error handler.

Changes:
   - Clear the ATA_QCFLAG_ACTIVE flag before calling the completion callback
     (and also before the error handler)
   - Add some comment

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 3544f5d..9a6aacf 100644 (file)
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3213,9 +3213,14 @@ void ata_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
        if (likely(qc->flags & ATA_QCFLAG_DMAMAP))
                ata_sg_clean(qc);
 
+       /* atapi: mark qc as inactive to prevent the interrupt handler
+        * from completing the command twice later, before the error handler
+        * is called. (when rc != 0 and atapi request sense is needed)
+        */
+       qc->flags &= ~ATA_QCFLAG_ACTIVE;
+
        /* call completion callback */
        rc = qc->complete_fn(qc, drv_stat);
-       qc->flags &= ~ATA_QCFLAG_ACTIVE;
 
        /* if callback indicates not to complete command (non-zero),
         * return immediately