libsas: Don't BUG when connecting two expanders via wide port
When a device is connected to an expander, the discovery process goes through
sas_ex_discover_dev to figure out what's attached to the phy. If it is the
case that the phy being discovered happens to be the second phy of a wide link
to an expander, that discover_dev function will incorrectly call
sas_ex_discover_expander, which creates another sas_port and tries to attach the
other sas_phys to the new port, thus triggering a BUG. The correct thing to do is
to check the other ex_phys of the expander to see if there's a sas_port for this
sas_phy, and attach the sas_phy to the existing sas_port.
This is easily triggered if one enables the phys of a wide port between
expanders one by one.
This second version of the patch fixes a small regression in the case where
all the phys show up at once and we accidentally try to attach to a port
that hasn't been created yet.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
drivers/scsi/libsas/sas_expander.c | 30 ++++++++++++++++++++++++++++++
1 files changed, 30 insertions(+), 0 deletions(-)
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 114e26c..2f3b8e1 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -736,6 +736,29 @@ static struct domain_device *sas_ex_disc
return NULL;
}
+/* See if this phy is part of a wide port */
+static int sas_ex_join_wide_port(struct domain_device *parent, int phy_id)
+{
+ struct ex_phy *phy = &parent->ex_dev.ex_phy[phy_id];
+ int i;
+
+ for (i = 0; i < parent->ex_dev.num_phys; i++) {
+ struct ex_phy *ephy = &parent->ex_dev.ex_phy[i];
+
+ if (ephy == phy)
+ continue;
+
+ if (!memcmp(phy->attached_sas_addr, ephy->attached_sas_addr,
+ SAS_ADDR_SIZE) && ephy->port) {
+ sas_port_add_phy(ephy->port, phy->phy);
+ phy->phy_state = PHY_DEVICE_DISCOVERED;
+ return 0;
+ }
+ }
+
+ return -ENODEV;
+}
+
static struct domain_device *sas_ex_discover_expander(
struct domain_device *parent, int phy_id)
{
@@ -868,6 +891,13 @@ static int sas_ex_discover_dev(struct do
return res;
}
+ res = sas_ex_join_wide_port(dev, phy_id);
+ if (!res) {
+ SAS_DPRINTK("Attaching ex phy%d to wide port %016llx\n",
+ phy_id, SAS_ADDR(ex_phy->attached_sas_addr));
+ return res;
+ }
+
switch (ex_phy->attached_dev_type) {
case SAS_END_DEV:
child = sas_ex_discover_end_dev(dev, phy_id);
-
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