1 files changed, 13 insertions, 11 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index d050e073e570..66aa4bee80a6 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2552,8 +2552,11 @@ static void atapi_qc_complete(struct ata_queued_cmd *qc)
                  *
                  * If door lock fails, always clear sdev->locked to
                  * avoid this infinite loop.
+                 *
+                 * This may happen before SCSI scan is complete.  Make
+                 * sure qc->dev->sdev isn't NULL before dereferencing.
                  */
-                if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL)
+                if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL && qc->dev->sdev)
                         qc->dev->sdev->locked = 0;
 
                 qc->scsicmd->result = SAM_STAT_CHECK_CONDITION;
@@ -3163,8 +3166,8 @@ static inline int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
 
 /**
  *      ata_scsi_queuecmd - Issue SCSI cdb to libata-managed device
+ *      @shost: SCSI host of command to be sent
  *      @cmd: SCSI command to be sent
- *      @done: Completion function, called when command is complete
  *
  *      In some cases, this function translates SCSI commands into
  *      ATA taskfiles, and queues the taskfiles to be sent to
@@ -3174,37 +3177,36 @@ static inline int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
  *      ATA and ATAPI devices appearing as SCSI devices.
  *
  *      LOCKING:
- *      Releases scsi-layer-held lock, and obtains host lock.
+ *      ATA host lock
  *
  *      RETURNS:
  *      Return value from __ata_scsi_queuecmd() if @cmd can be queued,
  *      0 otherwise.
  */
-int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
+int ata_scsi_queuecmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 {
         struct ata_port *ap;
         struct ata_device *dev;
         struct scsi_device *scsidev = cmd->device;
-        struct Scsi_Host *shost = scsidev->host;
         int rc = 0;
+        unsigned long irq_flags;
 
         ap = ata_shost_to_port(shost);
 
-        spin_unlock(shost->host_lock);
-        spin_lock(ap->lock);
+        spin_lock_irqsave(ap->lock, irq_flags);
 
         ata_scsi_dump_cdb(ap, cmd);
 
         dev = ata_scsi_find_dev(ap, scsidev);
         if (likely(dev))
-                rc = __ata_scsi_queuecmd(cmd, done, dev);
+                rc = __ata_scsi_queuecmd(cmd, cmd->scsi_done, dev);
         else {
                 cmd->result = (DID_BAD_TARGET << 16);
-                done(cmd);
+                cmd->scsi_done(cmd);
         }
 
-        spin_unlock(ap->lock);
-        spin_lock(shost->host_lock);
+        spin_unlock_irqrestore(ap->lock, irq_flags);
+
         return rc;
 }