[SCSI] libsas: fix loopback topology bug during discovery

In some test envirenment, there is loopback topology test. We should
handle this during discovery.

Signed-off-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 505ffe3582931f84d5061a11a9e3398e0c06eb13..f3f693b772ac17681b298872d69e5c2dd748882e 100644 (file)
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -244,6 +244,11 @@ static int sas_ex_phy_discover_helper(struct domain_device *dev, u8 *disc_req,
                 * dev to host FIS as described in section G.5 of
                 * sas-2 r 04b */
                dr = &((struct smp_resp *)disc_resp)->disc;
+               if (memcmp(dev->sas_addr, dr->attached_sas_addr,
+                         SAS_ADDR_SIZE) == 0) {
+                       sas_printk("Found loopback topology, just ignore it!\n");
+                       return 0;
+               }
                if (!(dr->attached_dev_type == 0 &&
                      dr->attached_sata_dev))
                        break;