[SCSI] libsas: Don't issue commands to devices that have been hot-removed

sd will get hung up issuing commands to flush write cache if a SAS
device behind the expander is unplugged without warning.  Change libsas
to reject commands to domain devices that have already gone away.

[maciej.trela@intel.com: removed setting ->gone in sas_deform_port() to
 permit sync cache commands at module removal]

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Tested-by: Haipao Fan <haipao.fan@intel.com>
Signed-off-by: Maciej Trela <maciej.trela@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index ddbade7beec9..e1a395b438ee 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -162,6 +162,10 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
         unsigned int xfer = 0;
         unsigned int si;
 
+        /* If the device fell off, no sense in issuing commands */
+        if (dev->gone)
+                return AC_ERR_SYSTEM;
+
         task = sas_alloc_task(GFP_ATOMIC);
         if (!task)
                 return AC_ERR_SYSTEM;