[SCSI] libsas: poll for ata device readiness after reset

Use ata_wait_after_reset() to poll for link recovery after a reset.
This combined with sas_ha->eh_mutex prevents expander rediscovery from
probing phys in an intermediate state.  Local discovery does not have a
mechanism to filter link status changes during this timeout, so it
remains the responsibility of lldds to prevent premature port teardown.
Although once all lldd's support ->lldd_ata_check_ready() that could be
used as a gate to local port teardown.

The signature fis is re-transmitted when the link comes back so we
should be revalidating the ata device class, but that is left to a future
patch.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 7c59f97c0287..32e417e6c2f7 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -125,7 +125,11 @@ static int smp_execute_task(struct domain_device *dev, void *req, int req_size,
                     task->task_status.stat == SAS_DATA_OVERRUN) {
                         res = -EMSGSIZE;
                         break;
-                } else {
+                }
+                if (task->task_status.resp == SAS_TASK_UNDELIVERED &&
+                    task->task_status.stat == SAS_DEVICE_UNKNOWN)
+                        break;
+                else {
                         SAS_DPRINTK("%s: task to dev %016llx response: 0x%x "
                                     "status 0x%x\n", __func__,
                                     SAS_ADDR(dev->sas_addr),
@@ -1648,8 +1652,8 @@ static int sas_get_phy_change_count(struct domain_device *dev,
         return res;
 }
 
-static int sas_get_phy_attached_sas_addr(struct domain_device *dev,
-                                         int phy_id, u8 *attached_sas_addr)
+int sas_get_phy_attached_sas_addr(struct domain_device *dev, int phy_id,
+                                  u8 *attached_sas_addr)
 {
         int res;
         struct smp_resp *disc_resp;